Tarka

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Tarka

Classes

Angiotensin Converting Enzyme Inhibitor/ACEIs and Calcium Channel Blocker Combinations

Administration
Oral Administration

Do not administer with grapefruit juice, which may significantly increase verapamil serum concentrations.

Oral Solid Formulations

Administer trandolapril; verapamil with food. Swallow tablets whole; do not break, crush, or chew.

Adverse Reactions
Severe

ileus / Delayed / 1.0-10.0
AV block / Early / 0.3-3.9
bradycardia / Rapid / 1.8-1.8
glomerulonephritis / Delayed / 0-1.0
renal tubular necrosis / Delayed / 0-1.0
hyperkalemia / Delayed / 0.4-0.8
azotemia / Delayed / 0.3-0.3
angioedema / Rapid / 0.1-0.1
myocardial infarction / Delayed / 0.3
laryngeal edema / Rapid / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known
hepatic failure / Delayed / Incidence not known
hepatic necrosis / Delayed / Incidence not known
pulmonary edema / Early / Incidence not known
heart failure / Delayed / Incidence not known
ventricular fibrillation / Early / Incidence not known
atrial fibrillation / Early / Incidence not known
hemolytic anemia / Delayed / Incidence not known
pancytopenia / Delayed / Incidence not known
agranulocytosis / Delayed / Incidence not known
aplastic anemia / Delayed / Incidence not known
exfoliative dermatitis / Delayed / Incidence not known
Stevens-Johnson syndrome / Delayed / Incidence not known
toxic epidermal necrolysis / Delayed / Incidence not known
pemphigus / Delayed / Incidence not known
erythema multiforme / Delayed / Incidence not known
teratogenesis / Delayed / Incidence not known
stroke / Early / Incidence not known
pancreatitis / Delayed / Incidence not known

Moderate

constipation / Delayed / 3.3-3.3
elevated hepatic enzymes / Delayed / 2.8-2.8
chest pain (unspecified) / Early / 2.2-2.2
edema / Delayed / 1.3-1.3
dyspnea / Early / 1.3-1.3
pneumonitis / Delayed / 0-1.0
hypotension / Rapid / 0.6-0.6
blurred vision / Early / 0.3
proteinuria / Delayed / 0.3
hematuria / Delayed / 0.3
confusion / Early / 0.3
gout / Delayed / 0.3
impotence (erectile dysfunction) / Delayed / 0.3
sinus tachycardia / Rapid / 0.3
palpitations / Early / 0.3
premature ventricular contractions (PVCs) / Early / 0.3
bundle-branch block / Early / 0.3
angina / Early / 0.3
neutropenia / Delayed / 0.3
leukopenia / Delayed / 0.3
hepatitis / Delayed / Incidence not known
jaundice / Delayed / Incidence not known
cholestasis / Delayed / Incidence not known
peripheral vasodilation / Rapid / Incidence not known
peripheral edema / Delayed / Incidence not known
gingival hyperplasia / Delayed / Incidence not known
thrombocytopenia / Delayed / Incidence not known
psychosis / Early / Incidence not known
galactorrhea / Delayed / Incidence not known
hyperprolactinemia / Delayed / Incidence not known

Mild

headache / Early / 8.9-8.9
cough / Delayed / 4.6-4.6
dizziness / Early / 3.1-3.1
fatigue / Early / 2.8-2.8
arthralgia / Delayed / 1.7-1.7
nausea / Early / 1.5-1.5
diarrhea / Early / 1.5-1.5
syncope / Early / 0.1-0.1
malaise / Early / 0.3
polyuria / Early / 0.3
insomnia / Early / 0.3
vertigo / Early / 0.3
nocturia / Early / 0.3
anxiety / Delayed / 0.3
drowsiness / Early / 0.3
epistaxis / Delayed / 0.3
pruritus / Rapid / 0.3
paresthesias / Delayed / 0.3
hypoesthesia / Delayed / 0.3
myalgia / Early / 0.3
rash / Early / 0.3
weakness / Early / 0.3
flushing / Rapid / 0.3
tinnitus / Delayed / 0.3
dyspepsia / Early / 0.3
xerostomia / Early / 0.3
gynecomastia / Delayed / Incidence not known
libido decrease / Delayed / Incidence not known
hyperkeratosis / Delayed / Incidence not known
photosensitivity / Delayed / Incidence not known
alopecia / Delayed / Incidence not known
urticaria / Rapid / Incidence not known
fever / Early / Incidence not known
increased urinary frequency / Early / Incidence not known
ecchymosis / Delayed / Incidence not known

Boxed Warning
Pregnancy

Drugs that affect the renin-angiotensin system (e.g., ACE inhibitors, angiotensin II receptor antagonists) reduce fetal renal function and increase fetal and neonatal morbidity and death when used during the second and third trimesters. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Other potential neonatal adverse effects include skull hypoplasia, anuria, and hypotension. Counsel females of child-bearing age on the consequences of trandolapril; verapamil exposure during pregnancy and discuss treatment options with those planning to become pregnant. Discontinue trandolapril; verapamil as soon as pregnancy is detected. In rare cases when another antihypertensive agent cannot be used to treat a pregnant patient, serial ultrasound examinations should be performed to assess the intraamniotic environment. If oligohydramnios is observed, discontinue trandolapril; verapamil unless it is considered life-saving for the mother. It should be noted that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe newborns with histories of in utero exposure to trandolapril; verapamil for hypotension, oliguria, and hyperkalemia. If oliguria or hypotension occurs, blood pressure and renal perfusion support may be required, as well as exchange transfusion or dialysis to reverse hypotension and/or support decreased renal function. Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensives in the first trimester have not distinguished between antihypertensive mechanism.[35075] Retrospective data indicate that first trimester use of ACE inhibitors has been associated with a potential risk of birth defects.[32294] However, a large observational study (n = 465,754) found that the risk of birth defects was similar in infants exposed to ACE inhibitors during the first trimester, in infants exposed to other antihypertensives during the first trimester, and in those whose mothers were hypertensive but were not treated.[46406] Infants born to mothers with hypertension, either treated or untreated, had a higher risk of birth defects than those born to mothers without hypertension. The authors concluded that the presence of hypertension likely contributed to the development of birth defects rather than the use of medications.

Common Brand Names

Tarka

Dea Class

Rx

Description

ACE inhibitor and CCB; used qd for HTN; oral combination product contains immediate-release trandolapril and extended-release verapamil; has greater antihypertensive effects than either agent alone.

Dosage And Indications
For the treatment of hypertension in patients who do not respond to monotherapy.
NOTE: Individualize the dosage by titration of the separate components. If the optimal dose corresponds to the ratio contained in the combination formulation, this product can be used for convenient dosing.
NOTE: The possibility of exacerbation of hypotensive effects with trandolapril; verapamil in patients taking diuretics may be minimized by either discontinuing the diuretic or cautiously increasing the salt intake prior to initiating this combination. If it is not possible to discontinue the diuretic, the starting dose should be reduced.
Oral dosage Adults

A patient whose blood pressure is not adequately controlled with either trandolapril or verapamil monotherapy may be given this combination drug product. Oral trandolapril and verapamil should be individually titrated to clinical goals before to switching to the appropriate dose ratio of Tarka (available in 2—180, 1—240, 2—240, and 4—240 mg of trandolapril and verapamil, respectively). Patients receiving diuretics should be initiated at lower doses. Maximum antihypertensive effects occur within about 1 week. Maximum dosage for combination therapy is 8 mg/day PO for trandolapril and 240 mg/day PO for verapamil. The recommended usual dosage range for trandolapril monotherapy is 1 to 4 mg/day administered once daily (or two divided doses). The recommended usual dosage range for monotherapy with sustained-release verapamil is 120 to 480 mg/day administered once daily (or two divided doses). Correct volume and/or sodium depletion prior to administration. Monitor closely for symptomatic hypotension.

Geriatric

Use the combination only after titrating the separate drug components. The initial doses of verapamil should be reduced in elderly patients. Greater sensitivity to the antihypertensive effects of verapamil and trandolapril is possible in elderly patients. Adjust the dosage based on clinical response.

Dosing Considerations
Hepatic Impairment

Use this combination drug product only after titrating the separate drug components. In patients with hepatic cirrhosis, the initial trandolapril dose is 0.5 mg/day and may be increased slowly (see Trandolapril monograph, Dosage section). In patients with hepatic disease, the verapamil initial dosage should be reduced to about 33% of the usual dosage (see Verapamil monograph, Dosage section). Verapamil and trandolapril dosage should be adjusted based on clinical response. The combination drug product has not been evaluated in subjects with impaired hepatic function.

Renal Impairment

CrCl > 30 ml/min: No dosage adjustment is necessary.
CrCl <= 30 ml/min: Use this combination drug product only after titrating the separate drug components. The initial trandolapril dose is 0.5 mg/day PO and may be increased slowly to a maximum of 2 mg/day PO (see Trandolapril monograph, Dosage section).
 
Intermittent hemodialysis
Use this combination drug product only after titrating the separate drug components. Verapamil and norverapamil are not removed by hemodialysis. Trandolaprilat is removed by hemodialysis; and hemodialysis patients have a reduced clearance of trandolaprilat. No specific dosage recommendations are available for dialysis patients.

Drug Interactions

Abemaciclib: (Moderate) Monitor for an increase in abemaciclib-related adverse reactions if coadministration with verapamil is necessary; consider reducing the dose of abemaciclib in 50-mg decrements if toxicities occur. Discontinue abemaciclib for patients unable to tolerate 50 mg twice daily. Abemaciclib is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration with verapamil is predicted to increase the relative potency adjusted unbound AUC of abemaciclib plus its active metabolites (M2, M18, and M20) by approximately 1.6-fold.
Acalabrutinib: (Major) Decrease the acalabrutinib dose to 100 mg PO once daily if coadministered with verapamil. Coadministration may result in increased acalabrutinib exposure and toxicity (e.g., infection, bleeding, and atrial arrhythmias). Acalabrutinib is a CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. In physiologically based pharmacokinetic (PBPK) simulations, the Cmax and AUC values of acalabrutinib were increased by 2- to almost 3-fold when acalabrutinib was coadministered with moderate CYP3A inhibitors.
Acebutolol: (Moderate) Use verapamil and acebutolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Acetaminophen; Aspirin, ASA; Caffeine: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown. (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Acetaminophen; Aspirin: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
Acetaminophen; Aspirin; Diphenhydramine: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
Acetaminophen; Caffeine: (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Acetaminophen; Caffeine; Dihydrocodeine: (Moderate) Concomitant use of dihydrocodeine with verapamil may increase dihydrocodeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased dihydromorphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of dihydrocodeine until stable drug effects are achieved. Discontinuation of verapamil could decrease dihydrocodeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to dihydrocodeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Verapamil is a moderate inhibitor of CYP3A4, an isoenzyme partially responsible for the metabolism of dihydrocodeine. (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Acetaminophen; Caffeine; Pyrilamine: (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Acetaminophen; Codeine: (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4.
Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Acetaminophen; Dextromethorphan; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Acetaminophen; Dichloralphenazone; Isometheptene: (Major) Isometheptene has sympathomimetic properties. Patients taking antihypertensive agents may need to have their therapy modified. Careful blood pressure monitoring is recommended. (Major) Isometheptene has sympathomimetic properties. Patients taking antihypertensive agents may need to have their therapy modified. Careful blood pressure monitoring is recommended.
Acetaminophen; Guaifenesin; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Acetaminophen; Hydrocodone: (Moderate) Consider a reduced dose of hydrocodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. It is recommended to avoid this combination when hydrocodone is being used for cough. Hydrocodone is a CYP3A4 substrate, and coadministration with CYP3A4 inhibitors like verapamil can increase hydrocodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of hydrocodone. These effects could be more pronounced in patients also receiving a CYP2D6 inhibitor. If verapamil is discontinued, hydrocodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to hydrocodone.
Acetaminophen; Ibuprofen: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Acetaminophen; Oxycodone: (Moderate) Consider a reduced dose of oxycodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. If verapamil is discontinued, consider increasing the oxycodone dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Oxycodone is a CYP3A4 substrate, and coadministration with a moderate inhibitor like verapamil can increase oxycodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of oxycodone. If verapamil is discontinued, oxycodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to oxycodone.
Acetaminophen; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Acetaminophen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Acrivastine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Adagrasib: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with adagrasib. Coadministration may increase the exposure of verapamil. Adagrasib is a strong inhibitor of CYP3A; verapamil is a substrate of CYP3A.
Adenosine: (Moderate) Use adenosine with caution in the presence of calcium-channel blockers due to the potential for additive or synergistic depressant effects on the sinoatrial and atrioventricular nodes.
Afatinib: (Moderate) If the concomitant use of verapamil and afatinib is necessary, monitor for afatinib-related adverse reactions. If the original dose of afatinib is not tolerated, consider reducing the daily dose of afatinib by 10 mg; resume the previous dose of afatinib as tolerated after discontinuation of verapamil. The manufacturer of afatinib recommends permanent discontinuation of therapy for severe or intolerant adverse drug reactions at a dose of 20 mg per day, but does not address a minimum dose otherwise. Afatinib is a P-glycoprotein (P-gp) substrate and verapamil is a P-gp inhibitor; coadministration may increase plasma concentrations of afatinib. Administration with another P-gp inhibitor, given 1 hour before a single dose of afatinib, increased afatinib exposure by 48%; there was no change in afatinib exposure when the P-gp inhibitor was administered at the same time as afatinib or 6 hours later. In healthy subjects, the relative bioavailability for AUC and Cmax of afatinib was 119% and 104%, respectively, when coadministered with the same P-gp inhibitor, and 111% and 105% when the inhibitor was administered 6 hours after afatinib.
Albuterol; Budesonide: (Moderate) Avoid coadministration of systemic budesonide with verapamil due to increased budesonide exposure; use caution with inhaled budesonide, as systemic exposure may increase. Budesonide is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor.
Aldesleukin, IL-2: (Moderate) Angiotensin converting enzyme inhibitors, like other antihypertensive agents, may potentiate the hypotension seen with aldesleukin, IL 2. (Moderate) Calcium channel blockers may potentiate the hypotension seen with aldesleukin, IL 2.
Alemtuzumab: (Moderate) Alemtuzumab may cause hypotension. Careful monitoring of blood pressure and hypotensive symptoms is recommended especially in patients with ischemic heart disease and in patients on antihypertensive agents. (Moderate) Alemtuzumab may cause hypotension. Careful monitoring of blood pressure and hypotensive symptoms is recommended especially in patients with ischemic heart disease and in patients on antihypertensive agents.
Alfentanil: (Moderate) Consider a reduced dose of alfentanil with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. If verapamil is discontinued, consider increasing the alfentanil dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Alfentanil is a sensitive CYP3A4 substrate, and coadministration with CYP3A4 inhibitors like verapamil can increase alfentanil exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of alfentanil. If verapamil is discontinued, alfentanil plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to alfentanil.
Alfuzosin: (Moderate) Monitor blood pressure if coadministration of alfuzosin and verapamil is necessary. This combination has the potential to cause hypotension in some patients. Coadministration may also result in increased alfuzosin serum concentrations. Alfuzosin is primarily metabolized by the CYP3A4 hepatic enzyme. In addition to potential for additive hypotension with alfuzosin, verapamil may also inhibit the metabolism of alfuzosin.
Aliskiren: (Major) Aliskiren-containing products are contraindicated in combination with angiotensin-converting enzyme inhibitors (ACE inhibitors) in patients with diabetes mellitus. In general, avoid combined use of two renin-angiotensin-aldosterone system (RAAS) inhibitors, particularly in patients with CrCl less than 60 mL/minute. Combination therapy increases the risk for hyperkalemia, renal impairment, and other side effects. Most patients receiving a comination of two RAAS inhibitors, such as ACE inhibitors and aliskiren do not obtain any additional benefit compared to monotherapy. Closely monitor blood pressure, renal function, and electrolytes if aliskiren must be combined with another RAAS inhibitor. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury. (Moderate) Administration of 240 mg verapamil with 300 mg aliskiren resulted in an approximately 2-fold increase in AUC and Cmax of aliskiren; however, no dosage adjustment is necessary. Blood pressure should be closely monitored in patients taking both of these medications.
Aliskiren; Hydrochlorothiazide, HCTZ: (Major) Aliskiren-containing products are contraindicated in combination with angiotensin-converting enzyme inhibitors (ACE inhibitors) in patients with diabetes mellitus. In general, avoid combined use of two renin-angiotensin-aldosterone system (RAAS) inhibitors, particularly in patients with CrCl less than 60 mL/minute. Combination therapy increases the risk for hyperkalemia, renal impairment, and other side effects. Most patients receiving a comination of two RAAS inhibitors, such as ACE inhibitors and aliskiren do not obtain any additional benefit compared to monotherapy. Closely monitor blood pressure, renal function, and electrolytes if aliskiren must be combined with another RAAS inhibitor. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury. (Moderate) Administration of 240 mg verapamil with 300 mg aliskiren resulted in an approximately 2-fold increase in AUC and Cmax of aliskiren; however, no dosage adjustment is necessary. Blood pressure should be closely monitored in patients taking both of these medications.
Almotriptan: (Minor) Verapamil, a moderate CYP3A4 inhibitor, increases AUC and peak plasma concentrations of almotriptan by 20% and 24%, respectively; however, per the manufacturer, the changes are not clinically significant and no dosage adjustment of almotriptan is needed. Some patients might rarely have an increase in common side effects of almotriptan, such as dizziness, nausea or drowsiness.
Alogliptin; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Alpha-glucosidase Inhibitors: (Moderate) ACE inhibitors may enhance the hypoglycemic effects of insulin or other antidiabetic agents by improving insulin sensitivity. Patients receiving antidiabetic agents can become hypoglycemic if ACE inhibitors are administered concomitantly. Patients receiving these drugs concomitantly with antidiabetic agents should be monitored for changes in glycemic control.
Alprazolam: (Major) Avoid coadministration of alprazolam and verapamil due to the potential for elevated alprazolam concentrations, which may cause prolonged sedation and respiratory depression. If coadministration is necessary, consider reducing the dose of alprazolam as clinically appropriate and monitor for an increase in alprazolam-related adverse reactions. Lorazepam, oxazepam, or temazepam may be safer alternatives if a benzodiazepine must be administered in combination with verapamil, as these benzodiazepines are not oxidatively metabolized. Alprazolam is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration with other moderate CYP3A4 inhibitors increased alprazolam exposure by 1.6- to 1.98-fold.
Alprostadil: (Minor) The concomitant use of systemic alprostadil injection and antihypertensive agents, like calcium channel blockers, may cause additive hypotension. Caution is advised with this combination. Systemic drug interactions with the urethral suppository (MUSE) or alprostadil intracavernous injection are unlikely in most patients because low or undetectable amounts of the drug are found in the peripheral venous circulation following administration. In those men with significant corpora cavernosa venous leakage, hypotension might be more likely. Use caution with in-clinic dosing for erectile dysfunction (ED) and monitor for the effects on blood pressure. In addition, the presence of medications in the circulation that attenuate erectile function may influence the response to alprostadil. However, in clinical trials with alprostadil intracavernous injection, anti-hypertensive agents had no apparent effect on the safety and efficacy of alprostadil. (Minor) The concomitant use of systemic alprostadil injection and antihypertensive agents, such as angiotensin-converting enzyme inhibitors (ACE inhibitors), may cause additive hypotension. Caution is advised with this combination. Systemic drug interactions with the urethral suppository (MUSE) or alprostadil intracavernous injection are unlikely in most patients because low or undetectable amounts of the drug are found in the peripheral venous circulation following administration. In those men with significant corpora cavernosa venous leakage, hypotension might be more likely. Use caution with in-clinic dosing for erectile dysfunction (ED) and monitor for the effects on blood pressure. However, in clinical trials with alprostadil intracavernous injection, anti-hypertensive agents had no apparent effect on the safety and efficacy of alprostadil.
Alvimopan: (Moderate) Alvimopan is a substrate of P-glycoprotein (P-gp). Although the concomitant use of mild to moderate inhibitors of P-gp did not influence the pharmacokinetics of alvimopan, the concomitant use of strong P-gp inhibitors, such as verapamil has not been studied. Coadministration of verapamil and alvimopan may result in elevated concentrations of alvimopan. If these drugs are coadministered, patients should be monitored for increased toxicity as well as increased therapeutic effect of alvimopan.
Amifostine: (Major) Patients receiving angiotensin-converting enzyme inhibitors should be closely monitored during amifostine infusions due to additive effects. Patients receiving amifostine at doses recommended for chemotherapy should have antihypertensive therapy interrupted 24 hours preceding administration of amifostine. If the antihypertensive cannot be stopped, patients should not receive amifostine. (Major) Patients receiving calcium-channel blockers should be closely monitored during amifostine infusions due to additive effects. Patients receiving amifostine at doses recommended for chemotherapy should have antihypertensive therapy interrupted 24 hours preceding administration of amifostine. If the antihypertensive cannot be stopped for 24 hours before chemotherapy doses of amifostine, patients should not receive amifostine.
Amiloride: (Major) Amiloride should be used very cautiously with agents that have potential to induce hyperkalemia; serum potassium levels monitored when such agents are coadministered with amiloride. Simultaneous use of a potassium-sparing diuretic (e.g., amiloride) with angiotensin-converting enzyme inhibitors (ACE inhibitors) can increase the risk of hyperkalemia, especially in the presence of renal impairment (renal disease, elderly patients). These agents should be used with caution and serum potassium levels monitored when the substances are coadministered. The Beers Criteria recommends avoiding routine use of this combination in older adults; reserve this combination for patients with demonstrated hypokalemia while taking an ACE inhibitor.
Amiloride; Hydrochlorothiazide, HCTZ: (Major) Amiloride should be used very cautiously with agents that have potential to induce hyperkalemia; serum potassium levels monitored when such agents are coadministered with amiloride. Simultaneous use of a potassium-sparing diuretic (e.g., amiloride) with angiotensin-converting enzyme inhibitors (ACE inhibitors) can increase the risk of hyperkalemia, especially in the presence of renal impairment (renal disease, elderly patients). These agents should be used with caution and serum potassium levels monitored when the substances are coadministered. The Beers Criteria recommends avoiding routine use of this combination in older adults; reserve this combination for patients with demonstrated hypokalemia while taking an ACE inhibitor.
Aminolevulinic Acid: (Minor) Preclinical data suggest that calcium-channel blockers could decrease the efficacy of photosensitizing agents used in photodynamic therapy.
Amiodarone: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with amiodarone. Coadministration may increase the exposure of verapamil. Additive effects on cardiac contractility and/or AV conduction are also possible. Verapamil is a substrate of CYP3A4 and amiodarone is a moderate CYP3A4 inhibitor.
Amlodipine: (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Amlodipine; Atorvastatin: (Moderate) Closely monitor for signs and symptoms of myopathy and rhabdomyolysis and consider atorvastatin dosage adjustment in patients also taking verapamil. Coadministration of verapamil, a P-gp inhibitor, with atorvastatin, a P-gp substrate, may increase atorvastatin exposure resulting in atorvastatin-related toxicity; the risk may be increased with higher statin doses. (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Amlodipine; Benazepril: (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Amlodipine; Celecoxib: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease. (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Amlodipine; Olmesartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy. (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Amlodipine; Valsartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy. (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Amlodipine; Valsartan; Hydrochlorothiazide, HCTZ: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy. (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Amobarbital: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added. (Moderate) Concurrent use of amobarbital with antihypertensive agents may lead to hypotension. Monitor for decreases in blood pressure during times of coadministration.
Amoxicillin; Clarithromycin; Omeprazole: (Major) Avoid coadministration of clarithromycin and verapamil, particularly in geriatric patients, due to an increased risk of hypotension and acute kidney injury. If the use of a macrolide antibiotic is necessary in a patient receiving verapamil therapy, azithromycin is the preferred agent. If coadministration is unavoidable, monitor blood pressure closely. Verapamil is a CYP3A4 substrate and clarithromycin is a strong CYP3A4 inhibitor. A retrospective, case crossover study, found the risk of hospitalization due to hypotension or shock to be significantly increased in geriatric patients exposed to clarithromycin during concurrent calcium-channel blocker therapy (OR 3.7, 95% CI 2.3-6.1). Concurrent use of azithromycin was not associated with an increased risk of hypotension (OR 1.5, 95% CI 0.8-2.8). One case of a possible verapamil-clarithromycin interaction was reported, which was associated with hypotension.
Amphetamine; Dextroamphetamine Salts: (Minor) Amphetamines increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, like angiotensin-converting enzyme inhibitors (ACE inhibitors). Close monitoring of blood pressure is advised. (Minor) Amphetamines increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, like calcium-channel blockers. Close monitoring of blood pressure is advised.
Angiotensin II receptor antagonists: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Angiotensin II: (Moderate) Angiotensin converting enzyme inhibitors (ACE inhibitors) may increase the response to angiotensin II. Angiotensin II is a naturally occurring peptide hormone of the renin-angiotensin-aldosterone system (RAAS) that causes vasoconstriction and an increase in blood pressure. ACE inhibitors reduce the breakdown of angiotensin II.
Apalutamide: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with apalutamide is necessary. Concomitant use may decrease plasma concentrations of verapamil. Verapamil is a CYP3A4 substrate and apalutamide is a strong CYP3A4 inducer.
Apomorphine: (Moderate) Use of angiotensin-converting enzyme inhibitors (ACE inhibitors) and apomorphine together can increase the hypotensive effects of apomorphine. Monitor blood pressure regularly during use of this combination. (Moderate) Use of calcium-channel blockers and apomorphine together can increase the hypotensive effects of apomorphine. Monitor blood pressure regularly during use of this combination.
Apraclonidine: (Minor) Alpha blockers as a class may reduce heart rate and blood pressure. While no specific drug interactions have been identified with systemic agents and apraclonidine during clinical trials, it is theoretically possible that additive blood pressure reductions could occur when apraclonidine is combined with the use of antihypertensive agents. Patients using cardiovascular drugs concomitantly with apraclonidine should have their pulse and blood pressure monitored periodically. (Minor) Apraclonidine had minimal effects on heart rate and blood pressure during clinical studies in patients with glaucoma. However, it is theoretically possible that additive blood pressure reductions could occur when apraclonidine is combined with the use of antihypertensive agents. Use caution during concurrent use, especially in patients with severe, uncontrolled cardiovascular disease, including hypertension.
Aprepitant, Fosaprepitant: (Major) Avoid the concomitant use of verapamil with aprepitant, fosaprepitant due to substantially increased exposure of aprepitant; increased verapamil exposure may also occur. If coadministration cannot be avoided, use caution and monitor for an increase in verapamil- and aprepitant-related adverse effects for several days after administration of a multi-day aprepitant regimen. Verapamil is a moderate CYP3A4 inhibitor and aprepitant is a CYP3A4 substrate. Coadministration of daily oral aprepitant (230 mg, or 1.8 times the recommended single dose) with a moderate CYP3A4 inhibitor, diltiazem, increased the aprepitant AUC 2-fold with a concomitant 1.7-fold increase in the diltiazem AUC; clinically meaningful changes in ECG, heart rate, or blood pressure beyond those induced by diltiazem alone did not occur. Verapamil is also a CYP3A4 substrate. Aprepitant, when administered as a 3-day oral regimen (125 mg/80 mg/80 mg), is a moderate CYP3A4 inhibitor and inducer and may additionally increase plasma concentrations of verapamil. For example, a 5-day oral aprepitant regimen increased the AUC of another CYP3A4 substrate, midazolam (single dose), by 2.3-fold on day 1 and by 3.3-fold on day 5. After a 3-day oral aprepitant regimen, the AUC of midazolam (given on days 1, 4, 8, and 15) increased by 25% on day 4, and then decreased by 19% and 4% on days 8 and 15, respectively. As a single 125 mg or 40 mg oral dose, the inhibitory effect of aprepitant on CYP3A4 is weak, with the AUC of midazolam increased by 1.5-fold and 1.2-fold, respectively. After administration, fosaprepitant is rapidly converted to aprepitant and shares many of the same drug interactions. However, as a single 150 mg intravenous dose, fosaprepitant only weakly inhibits CYP3A4 for a duration of 2 days; there is no evidence of CYP3A4 induction. Fosaprepitant 150 mg IV as a single dose increased the AUC of midazolam (given on days 1 and 4) by approximately 1.8-fold on day 1; there was no effect on day 4. Less than a 2-fold increase in the midazolam AUC is not considered clinically important. Finally, aprepitant is a CYP2C9 inducer and verapamil is a CYP2C9 substrate. Administration of a CYP2C9 substrate, tolbutamide, on days 1, 4, 8, and 15 with a 3-day regimen of oral aprepitant (125 mg/80 mg/80 mg) decreased the tolbutamide AUC by 23% on day 4, 28% on day 8, and 15% on day 15. The AUC of tolbutamide was decreased by 8% on day 2, 16% on day 4, 15% on day 8, and 10% on day 15 when given prior to oral administration of aprepitant 40 mg on day 1, and on days 2, 4, 8, and 15. The effects of aprepitant on tolbutamide were not considered significant.
Aprotinin: (Moderate) The manufacturer recommends using aprotinin cautiously in patients that are receiving drugs that can affect renal function, such as ACE inhibitors, as the risk of renal impairment may be increased.
Aripiprazole: (Moderate) Monitor for aripiprazole-related adverse reactions during concomitant use of verapamil. Patients receiving both a CYP2D6 inhibitor plus verapamil may require an aripiprazole dosage adjustment. Dosing recommendations vary based on aripiprazole dosage form, CYP2D6 inhibitor strength, and CYP2D6 metabolizer status. See prescribing information for details. Concomitant use may increase aripiprazole exposure and risk for side effects. Aripiprazole is a CYP3A and CYP2D6 substrate; verapamil is a moderate CYP3A inhibitor. (Minor) Aripiprazole may enhance the hypotensive effects of antihypertensive agents.
Articaine; Epinephrine: (Moderate) Antihypertensives, including angiotensin-converting enzyme inhibitors, antagonize the vasopressor effects of parenteral epinephrine. (Moderate) Antihypertensives, including calcium-channel blockers, antagonize the vasopressor effects of parenteral epinephrine.
Asenapine: (Moderate) Secondary to alpha-blockade, asenapine can produce vasodilation that may result in additive effects during concurrent use of antihypertensive agents. The potential reduction in blood pressure can precipitate orthostatic hypotension and associated dizziness, tachycardia, and syncope. If concurrent use of asenapine and antihypertensive agents is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known.
Aspirin, ASA: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
Aspirin, ASA; Butalbital; Caffeine: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added. (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown. (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Aspirin, ASA; Caffeine: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown. (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Aspirin, ASA; Caffeine; Orphenadrine: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown. (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Aspirin, ASA; Carisoprodol: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
Aspirin, ASA; Carisoprodol; Codeine: (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4. (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
Aspirin, ASA; Citric Acid; Sodium Bicarbonate: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
Aspirin, ASA; Dipyridamole: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
Aspirin, ASA; Omeprazole: (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
Aspirin, ASA; Oxycodone: (Moderate) Consider a reduced dose of oxycodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. If verapamil is discontinued, consider increasing the oxycodone dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Oxycodone is a CYP3A4 substrate, and coadministration with a moderate inhibitor like verapamil can increase oxycodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of oxycodone. If verapamil is discontinued, oxycodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to oxycodone. (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown.
Atazanavir: (Moderate) Coadministration of ritonavir with verapamil may increase the serum concentrations of verapamil, potentially resulting in verapamil toxicity. The manufacturer for ritonavir recommends caution when coadministering this combination. A similar effect could be expected with other anti-retroviral protease inhibitors, which are also inhibitors of CYP3A4.
Atazanavir; Cobicistat: (Moderate) Coadministration of cobicistat (a strong CYP3A4 inhibitor) with calcium-channel blockers metabolized by CYP3A4, such as verapamil, may result in elevated calcium-channel blockers serum concentrations. If used concurrently, close clinical monitoring with appropriate dose reductions are advised. (Moderate) Coadministration of ritonavir with verapamil may increase the serum concentrations of verapamil, potentially resulting in verapamil toxicity. The manufacturer for ritonavir recommends caution when coadministering this combination. A similar effect could be expected with other anti-retroviral protease inhibitors, which are also inhibitors of CYP3A4.
Atenolol: (Moderate) Use verapamil and atenolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Atenolol; Chlorthalidone: (Moderate) Use verapamil and atenolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Atorvastatin: (Moderate) Closely monitor for signs and symptoms of myopathy and rhabdomyolysis and consider atorvastatin dosage adjustment in patients also taking verapamil. Coadministration of verapamil, a P-gp inhibitor, with atorvastatin, a P-gp substrate, may increase atorvastatin exposure resulting in atorvastatin-related toxicity; the risk may be increased with higher statin doses.
Atorvastatin; Ezetimibe: (Moderate) Closely monitor for signs and symptoms of myopathy and rhabdomyolysis and consider atorvastatin dosage adjustment in patients also taking verapamil. Coadministration of verapamil, a P-gp inhibitor, with atorvastatin, a P-gp substrate, may increase atorvastatin exposure resulting in atorvastatin-related toxicity; the risk may be increased with higher statin doses.
Avanafil: (Major) Do not exceed an avanafil dose of 50 mg once every 24 hours in patients receiving verapamil. Coadministration may increase avanafil exposure. Avanafil is a sensitive CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. Administration of another moderate CYP3A4 inhibitor increased the avanafil AUC by 3-fold and prolonged the half-life to approximately 8 hours.
Avapritinib: (Major) Avoid coadministration of avapritinib with verapamil due to the risk of increased avapritinib-related adverse reactions. If concurrent use is unavoidable, reduce the starting dose of avapritinib from 300 mg PO once daily to 100 mg PO once daily in patients with gastrointestinal stromal tumor or from 200 mg PO once daily to 50 mg PO once daily in patients with advanced systemic mastocytosis. Avapritinib is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration of avapritinib 300 mg PO once daily with a moderate CYP3A4 inhibitor is predicted to increase the AUC of avapritinib by 210% at steady-state.
Azathioprine: (Major) The use of ACE inhibitors in hypertensive patients receiving azathioprine has been reported to induce anemia and severe leukopenia. This combination should be avoided where possible. When concurrent azathioprine and ACE inhibitor therapy is necessary, the patient should be monitored cautiously for potential myelosuppression.
Azilsartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Azilsartan; Chlorthalidone: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Baclofen: (Moderate) Baclofen has been associated with hypotension. Concurrent use with baclofen and antihypertensive agents may result in additive hypotension. Dosage adjustments of the antihypertensive medication may be required.
Barbiturates: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added.
Benzhydrocodone; Acetaminophen: (Moderate) Concurrent use of benzhydrocodone with verapamil may increase the risk of increased opioid-related adverse reactions, such as fatal respiratory depression. Consider a dose reduction of benzhydrocodone until stable drug effects are achieved. Monitor patients for respiratory depression and sedation at frequent intervals. Discontinuation of verapamil in a patient taking benzhydrocodone may decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to opioid agonists. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Benzhydrocodone is a prodrug for hydrocodone. Hydrocodone is a substrate for CYP3A4. Verapamil is an inhibitor of CYP3A4.
Benzphetamine: (Minor) Benzphetamine may increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, like angiotensin-converting enzyme inhibitors (ACE inhibitors). Close monitoring of blood pressure is advised. (Minor) Benzphetamine might increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, like calcium-channel blockers. Close monitoring of blood pressure is advised.
Berotralstat: (Major) Reduce the berotralstat dose to 110 mg PO once daily in patients chronically taking verapamil. Concurrent use may increase berotralstat exposure and the risk of adverse effects. Additionally, monitor blood pressure and heart rate as concurrent use may also increase verapamil exposure. Berotralstat is a P-gp substrate and moderate CYP3A4 inhibitor; verapamil is a CYP3A4 substrate and P-gp inhibitor. Coadministration with another P-gp inhibitor increased berotralstat exposure by 69%.
Betaxolol: (Moderate) Use verapamil and betaxolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Betrixaban: (Major) Avoid betrixaban use in patients with severe renal impairment receiving verapamil. Reduce betrixaban dosage to 80 mg PO once followed by 40 mg PO once daily in all other patients receiving verapamil. Bleeding risk may be increased; monitor patients closely for signs and symptoms of bleeding. Betrixaban is a substrate of P-gp; verapamil inhibits P-gp.
Bictegravir; Emtricitabine; Tenofovir Alafenamide: (Moderate) Coadministration of tenofovir alafenamide with verapamil may result in increased plasma concentrations of tenofovir leading to an increase in tenofovir-related adverse effects. Tenofovir alafenamide is a P-gp substrate and verapamil is a P-gp inhibitor.
Bisoprolol: (Moderate) Use verapamil and bisoprolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Bisoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Use verapamil and bisoprolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Bortezomib: (Moderate) Patients on antihypertensive agents receiving bortezomib treatment may require close monitoring of their blood pressure and dosage adjustment of their medication. During clinical trials of bortezomib, hypotension was reported in roughly 12 percent of patients.
Bosentan: (Moderate) Closely monitor blood pressure and for increased bosentan toxicity if coadministration of verapamil with bosentan is necessary; decreased verapamil and/or increased bosentan plasma concentrations may occur. Verapamil is a CYP3A4 substrate and inhibitor; bosentan is a CYP3A4 substrate and moderate CYP3A4 inducer.
Bo

sutinib: (Major) Avoid concomitant use of bosutinib and verapamil or as bosutinib plasma exposure may be significantly increased resulting in an increased risk of bosutinib adverse events (e.g., myelosuppression, GI toxicity). Bosutinib is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. In a cross-over trial in 18 healthy volunteers, the Cmax and AUC values of bosutinib were increased 1.5-fold and 2-fold, respectively, when bosutinib 500 mg PO was administered with a single dose of a moderate CYP3A4 inhibitor.
Brexpiprazole: (Moderate) Because brexpiprazole is primarily metabolized by CYP3A4 and CYP2D6, systemic exposure may be increased during use of a moderate CYP3A4 inhibitor such as verapamil and careful monitoring is advisable. In addition, the manufacturer recommends that the brexpiprazole dose be reduced to one-quarter (25%) of the usual dose in patients receiving a moderate to strong inhibitor of CYP3A4 in combination with a moderate to strong inhibitor of CYP2D6. If verapamil is used in combination with brexpiprazole and a moderate to strong CYP2D6 inhibitor, the brexpiprazole dose should be adjusted and the patient should be carefully monitored for brexpiprazole-related adverse reactions. (Moderate) Due to brexpiprazole's antagonism at alpha 1-adrenergic receptors, the drug may enhance the hypotensive effects of alpha-blockers and other antihypertensive agents.
Brigatinib: (Major) Avoid coadministration of brigatinib with verapamil if possible due to increased plasma exposure of brigatinib; increased verapamil concentrations may also occur. If concomitant use is unavoidable, reduce the dose of brigatinib by approximately 40% without breaking tablets (i.e., from 180 mg to 120 mg; from 120 mg to 90 mg; from 90 mg to 60 mg); after discontinuation of verapamil, resume the brigatinib dose that was tolerated prior to initiation of verapamil. Monitor blood pressure and heart rate. Brigatinib is a CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. Coadministration with a moderate CYP3A4 inhibitor is predicted to increase the AUC of brigatinib by approximately 40%. Additionally, verapamil is a P-glycoprotein (P-gp) substrate. Brigatinib is a P-gp inhibitor in vitro and may have the potential to increase concentrations of P-gp substrates.
Brimonidine; Timolol: (Moderate) Use verapamil and timolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Bromocriptine: (Major) When bromocriptine is used for diabetes, do not exceed a dose of 1.6 mg once daily during concomitant use of verapamil. Use this combination with caution in patients receiving bromocriptine for other indications. Concurrent use may increase bromocriptine concentrations. Bromocriptine is extensively metabolized in the liver via CYP3A4; verapamil is a moderate inhibitor of CYP3A4. Administration of bromocriptine with a moderate inhibitor of CYP3A4 increased the bromocriptine mean AUC and Cmax by 3.7-fold and 4.6-fold, respectively.
Brompheniramine; Dextromethorphan; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Brompheniramine; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Brompheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Budesonide: (Moderate) Avoid coadministration of systemic budesonide with verapamil due to increased budesonide exposure; use caution with inhaled budesonide, as systemic exposure may increase. Budesonide is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor.
Budesonide; Formoterol: (Moderate) Avoid coadministration of systemic budesonide with verapamil due to increased budesonide exposure; use caution with inhaled budesonide, as systemic exposure may increase. Budesonide is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor.
Budesonide; Glycopyrrolate; Formoterol: (Moderate) Avoid coadministration of systemic budesonide with verapamil due to increased budesonide exposure; use caution with inhaled budesonide, as systemic exposure may increase. Budesonide is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor.
Bupivacaine Liposomal: (Moderate) Verapamil may inhibit the CYP3A4-mediated metabolism of and bupivacaine. Use caution when administering these drugs concomitantly.
Bupivacaine: (Moderate) Verapamil may inhibit the CYP3A4-mediated metabolism of and bupivacaine. Use caution when administering these drugs concomitantly.
Bupivacaine; Epinephrine: (Moderate) Antihypertensives, including angiotensin-converting enzyme inhibitors, antagonize the vasopressor effects of parenteral epinephrine. (Moderate) Antihypertensives, including calcium-channel blockers, antagonize the vasopressor effects of parenteral epinephrine. (Moderate) Verapamil may inhibit the CYP3A4-mediated metabolism of and bupivacaine. Use caution when administering these drugs concomitantly.
Bupivacaine; Lidocaine: (Moderate) Concomitant use of systemic lidocaine and verapamil may increase lidocaine plasma concentrations by decreasing lidocaine clearance and therefore prolonging the elimination half-life. Monitor for lidocaine toxicity if used together. Lidocaine is a CYP3A4 and CYP1A2 substrate; verapamil inhibits both hepatic isoenzymes. (Moderate) Verapamil may inhibit the CYP3A4-mediated metabolism of and bupivacaine. Use caution when administering these drugs concomitantly.
Bupivacaine; Meloxicam: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease. (Moderate) Verapamil may inhibit the CYP3A4-mediated metabolism of and bupivacaine. Use caution when administering these drugs concomitantly.
Buprenorphine: (Moderate) Concomitant use of buprenorphine and verapamil can increase the plasma concentration of buprenorphine, resulting in increased or prolonged opioid effects, particularly when verapamil is added after a stable buprenorphine dose is achieved. If concurrent use is necessary, consider dosage reduction of buprenorphine until stable drug effects are achieved. Monitor patient for respiratory depression and sedation at frequent intervals. When stopping verapamil, the buprenorphine concentration may decrease, potentially resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependency. If verapamil is discontinued, consider increasing buprenorphine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. Buprenorphine is a substrate of CYP3A4 and verapamil is a CYP3A4 inhibitor.
Buprenorphine; Naloxone: (Moderate) Concomitant use of buprenorphine and verapamil can increase the plasma concentration of buprenorphine, resulting in increased or prolonged opioid effects, particularly when verapamil is added after a stable buprenorphine dose is achieved. If concurrent use is necessary, consider dosage reduction of buprenorphine until stable drug effects are achieved. Monitor patient for respiratory depression and sedation at frequent intervals. When stopping verapamil, the buprenorphine concentration may decrease, potentially resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependency. If verapamil is discontinued, consider increasing buprenorphine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. Buprenorphine is a substrate of CYP3A4 and verapamil is a CYP3A4 inhibitor.
Buspirone: (Moderate) Monitor for an increase in buspirone-related adverse reactions if coadministration with verapamil is necessary; the effect may be more pronounced if the patient has been titrated to a stable dose of buspirone and verapamil is added or removed from therapy. Buspirone is a sensitive CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with other moderate CYP3A inhibitors increased buspirone exposure by 3.4 to 6-fold and was accompanied by increased buspirone-related adverse reactions.
Butabarbital: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added.
Butalbital; Acetaminophen: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added.
Butalbital; Acetaminophen; Caffeine: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added. (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Butalbital; Acetaminophen; Caffeine; Codeine: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added. (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4. (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Butalbital; Aspirin; Caffeine; Codeine: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added. (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4. (Minor) In a few reported cases, coadministration of verapamil with aspirin, ASA has led to increased bleeding times greater than observed with aspirin alone. The exact mechanism and clinical significance of this interaction is unknown. (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Cabergoline: (Moderate) Cabergoline should be used cautiously with antihypertensive agents, including angiotensin-converting enzyme inhibitors. Cabergoline has been associated with hypotension. Initial doses of cabergoline higher than 1 mg may produce orthostatic hypotension. It may be advisable to monitor blood pressure. (Moderate) Cabergoline should be used cautiously with antihypertensive agents, including verapamil. Cabergoline has been associated with hypotension. Initial doses of cabergoline higher than 1 mg may produce orthostatic hypotension. It may be advisable to monitor blood pressure. In addition, the prolactin-lowering effect of cabergoline may be diminished by medications that increase prolactin levels such as verapamil. Monitor for reduced response to cabergoline.
Cabotegravir; Rilpivirine: (Moderate) Close clinical monitoring is advised when administering verapamil with rilpivirine due to an increased potential for rilpivirine-related adverse events. Although this interaction has not been studied, predictions can be made based on metabolic pathways. Verapamil is an inhibitor of the hepatic isoenzyme CYP3A4; rilpivirine is metabolized by this isoenzyme. Coadministration may result in increased rilpivirine plasma concentrations.
Cabozantinib: (Minor) Monitor for an increase in verapamil-related adverse reactions if coadministration with cabozantinib is necessary. Verapamil is a P-glycoprotein (P-gp) substrate. Cabozantinib is a P-gp inhibitor and has the potential to increase plasma concentrations of P-gp substrates; however, the clinical relevance of this finding is unknown.
Caffeine: (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects. (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Caffeine; Sodium Benzoate: (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Calcium Phosphate, Supersaturated: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as angiotensin-converting enzyme inhibitors, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
Calcium: (Minor) Monitor blood pressure during concurrent use of calcium and calcium-channel blockers. Concomitant use may reduce the response to calcium-channel blockers.
Canagliflozin; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Candesartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Candesartan; Hydrochlorothiazide, HCTZ: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Carbamazepine: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with carbamazepine is necessary. Additionally, monitor carbamazepine concentrations closely during coadministration; carbamazepine dose adjustments may be needed. Concomitant use may decrease exposure of verapamil and increase exposure of carbamazepine. Verapamil is a CYP3A substrate and moderate CYP3A inhibitor; carbamazepine is a CYP3A substrate and strong CYP3A inducer.
Carbidopa; Levodopa: (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects. (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects.
Carbidopa; Levodopa; Entacapone: (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects. (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects.
Cariprazine: (Moderate) Cariprazine and its active metabolites are extensively metabolized by CYP3A4. Verapamil is a moderate inhibitor of CYP3A4 and may reduce the hepatic metabolism of CYP3A4 substrates, although the impact of moderate CYP3A4 inhibitors on cariprazine metabolism has not been studied. Monitoring for adverse effects, such as CNS effects and extrapyramidal symptoms, is advisable during coadministration. In addition, orthostatic vital signs should be monitored in patients who are at risk for hypotension, such as those receiving cariprazine in combination with antihypertensive agents. Atypical antipsychotics may cause orthostatic hypotension and syncope, most commonly during treatment initiation and dosage increases. Patients should be informed about measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning, or rising slowly from a seated position. Consider a cariprazine dose reduction if hypotension occurs. (Moderate) Orthostatic vital signs should be monitored in patients who are at risk for hypotension, such as those receiving cariprazine in combination with antihypertensive agents. Atypical antipsychotics may cause orthostatic hypotension and syncope, most commonly during treatment initiation and dosage increases. Patients should be informed about measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning, or rising slowly from a seated position. Consider a cariprazine dose reduction if hypotension occurs.
Carteolol: (Moderate) Oral calcium-channel blockers and beta-blockers like carteolol are used together for their therapeutic benefits to reduce angina and improve exercise tolerance. However, concomitant administration of beta-adrenergic blocking agents and verapamil can lead to significant AV nodal blockade. This can manifest as heart block, bradycardia, cardiac conduction abnormalities and/or prolonged PR interval. Congestive heart failure or severe hypotension also can occur. The combination of beta-blockers and verapamil should be avoided in patients with poor ventricular function due to increased negative inotropic effects.
Carvedilol: (Moderate) Use verapamil and carvedilol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. Monitor ECG and blood pressure if verapamil is coadministered with carvedilol. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Celecoxib: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Celecoxib; Tramadol: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Ceritinib: (Major) Avoid concomitant use of ceritinib with verapamil if possible due to the risk of additive bradycardia; verapamil exposure may also increase. Both ceritinib and verapamil can cause bradycardia. An interruption of ceritinib therapy, dose reduction, or discontinuation of therapy may be necessary if bradycardia occurs. Monitor blood pressure and heart rate. Diltiazem is a CYP3A4 substrate and ceritinib is a strong CYP3A4 inhibitor.
Cetirizine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Chlordiazepoxide: (Moderate) Verapamil is a CYP3A4 inhibitor and may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Chlordiazepoxide; Amitriptyline: (Moderate) Verapamil is a CYP3A4 inhibitor and may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Chlordiazepoxide; Clidinium: (Moderate) Verapamil is a CYP3A4 inhibitor and may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Chloroprocaine: (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents. (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents.
Chlorpheniramine; Codeine: (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4.
Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Moderate) Concomitant use of dihydrocodeine with verapamil may increase dihydrocodeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased dihydromorphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of dihydrocodeine until stable drug effects are achieved. Discontinuation of verapamil could decrease dihydrocodeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to dihydrocodeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Verapamil is a moderate inhibitor of CYP3A4, an isoenzyme partially responsible for the metabolism of dihydrocodeine. (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Chlorpheniramine; Hydrocodone: (Moderate) Consider a reduced dose of hydrocodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. It is recommended to avoid this combination when hydrocodone is being used for cough. Hydrocodone is a CYP3A4 substrate, and coadministration with CYP3A4 inhibitors like verapamil can increase hydrocodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of hydrocodone. These effects could be more pronounced in patients also receiving a CYP2D6 inhibitor. If verapamil is discontinued, hydrocodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to hydrocodone.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Chlorpheniramine; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Chlorpheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Chlorthalidone; Clonidine: (Moderate) Avoid concomitant use of verapamil and extended-release clonidine tablets. Monitor heart rate during concomitant use of verapamil and other clonidine formulations. Concomitant use may potentiate bradycardia and risk of AV block. Sinus bradycardia resulting in hospitalization and pacemaker insertion has been reported during the use of verapamil and clonidine.
Cilostazol: (Major) Cilostazol clearance may be impaired by inhibitors of the CYP3A4 hepatic microsomal isoenzyme, including verapamil. When verapamil is coadministered with cilostazol, the manufacturer recommends that the cilostazol dosage be reduced by 50%.
Cimetidine: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with cimetidine. Coadministration may increase the exposure of verapamil.
Cisapride: (Contraindicated) Postmarketing surveillance reports have documented QT prolongation and ventricular arrhythmias, including torsade de pointes and death, when known and potent inhibitors of CYP3A4 are coadministered with cisapride. Verapamil may have the potential to inhibit the metabolism of cisapride through CYP3A4 and thus, should not be used with cisapride.
Cisplatin: (Minor) The absorption of verapamil can be reduced by the vindesine, doxorubicin, cisplatin (VAC) chemotherapeutic drug regimen.
Clarithromycin: (Major) Avoid coadministration of clarithromycin and verapamil, particularly in geriatric patients, due to an increased risk of hypotension and acute kidney injury. If the use of a macrolide antibiotic is necessary in a patient receiving verapamil therapy, azithromycin is the preferred agent. If coadministration is unavoidable, monitor blood pressure closely. Verapamil is a CYP3A4 substrate and clarithromycin is a strong CYP3A4 inhibitor. A retrospective, case crossover study, found the risk of hospitalization due to hypotension or shock to be significantly increased in geriatric patients exposed to clarithromycin during concurrent calcium-channel blocker therapy (OR 3.7, 95% CI 2.3-6.1). Concurrent use of azithromycin was not associated with an increased risk of hypotension (OR 1.5, 95% CI 0.8-2.8). One case of a possible verapamil-clarithromycin interaction was reported, which was associated with hypotension.
Clofarabine: (Moderate) Concomitant use of clofarabine, a substrate of OCT1, and verapamil, an inhibitor of OCT1, may result in increased clofarabine levels. Therefore, monitor for signs of clofarabine toxicity such as gastrointestinal toxicity (e.g., nausea, vomiting, diarrhea, mucosal inflammation), hematologic toxicity, and skin toxicity (e.g., hand and foot syndrome, rash, pruritus) in patients also receiving OCT1 inhibitors.
Clonazepam: (Moderate) Monitor for increased sedation and respiratory depression if clonazepam is coadministered with verapamil; adjust the dose of clonazepam if necessary. The systemic exposure of clonazepam may be increased resulting in an increase in treatment-related adverse reactions. Clonazepam is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor.
Clonidine: (Moderate) Avoid concomitant use of verapamil and extended-release clonidine tablets. Monitor heart rate during concomitant use of verapamil and other clonidine formulations. Concomitant use may potentiate bradycardia and risk of AV block. Sinus bradycardia resulting in hospitalization and pacemaker insertion has been reported during the use of verapamil and clonidine.
Clorazepate: (Moderate) CYP3A4 inhibitors, such as verapamil, may reduce the metabolism of clorazepate and increase the potential for benzodiazepine toxicity.
Clozapine: (Moderate) Caution is advisable during concurrent use of verapamil and clozapine. Verapamil is an inhibitor of CYP3A4, one of the isoenzymes responsible for the metabolism of clozapine. Treatment with clozapine has been associated with QT prolongation, torsade de pointes (TdP), cardiac arrest, and sudden death. Elevated plasma concentrations of clozapine occurring through CYP inhibition may potentially increase the risk of life-threatening arrhythmias, sedation, anticholinergic effects, seizures, orthostasis, or other adverse effects. According to the manufacturer, patients receiving clozapine in combination with an inhibitor of CYP3A4 should be monitored for adverse reactions. Consideration should be given to reducing the clozapine dose if necessary. If the inhibitor is discontinued after dose adjustments are made, monitor for lack of clozapine effectiveness and consider increasing the clozapine dose if necessary. (Moderate) Lisinopril may decrease the renal elimination of clozapine and metabolites. Clozapine toxicity, including irritability, anger, insomnia, nightmares and sialorrhea may occur. The mechanism of this interaction is unclear; however, as lisinopril does not undergo metabolism, cytochrome P450 enzyme involvement is unlikely. It is speculated that a decrease in renal elimination of clozapine occurs due to a lisinopril-induced reduction in glomerular filtration rate (GFR). Plasma clozapine concentrations should be measured carefully during concomitant lisinopril therapy; another antihypertensive class may need to be selected. In addition, clozapine used concomitantly with the antihypertensive agents can increase the risk and severity of hypotension by potentiating the effect of the antihypertensive drug.
Cobicistat: (Moderate) Coadministration of cobicistat (a strong CYP3A4 inhibitor) with calcium-channel blockers metabolized by CYP3A4, such as verapamil, may result in elevated calcium-channel blockers serum concentrations. If used concurrently, close clinical monitoring with appropriate dose reductions are advised.
Cobimetinib: (Major) Avoid the concurrent use of cobimetinib with chronic verapamil therapy due to the risk of cobimetinib toxicity. If concurrent short-term (14 days or less) use of verapamil is unavoidable, reduce the dose of cobimetinib to 20 mg once daily for patients normally taking 60 mg daily; after discontinuation of verapamil, resume cobimetinib at the previous dose. Use an alternative to verapamil in patients who are already taking a reduced dose of cobimetinib (40 or 20 mg daily). Cobimetinib is a P-glycoprotein (P-gp) substrate as well as a CYP3A substrate in vitro; verapamil is a moderate inhibitor of both CYP3A and P-gp. In healthy subjects (n = 15), coadministration of a single 10 mg dose of cobimetinib with itraconazole (200 mg once daily for 14 days), a strong CYP3A4 inhibitor, increased the mean cobimetinib AUC by 6.7-fold (90% CI, 5.6 to 8) and the mean Cmax by 3.2-fold (90% CI, 2.7 to 3.7).
Cocaine: (Major) Use of cocaine with antihypertensive agents may increase the antihypertensive effects of the antihypertensive medications or may potentiate cocaine-induced sympathetic stimulation. (Major) Use of cocaine with antihypertensive agents may increase the antihypertensive effects of the antihypertensive medications or may potentiate cocaine-induced sympathetic stimulation.
Codeine: (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4.
Codeine; Guaifenesin: (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4.
Codeine; Guaifenesin; Pseudoephedrine: (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Codeine; Phenylephrine; Promethazine: (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4. (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Codeine; Promethazine: (Moderate) Concomitant use of codeine with verapamil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of verapamil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Verapamil is a moderate inhibitor of CYP3A4.
Co-Enzyme Q10, Ubiquinone: (Moderate) Co-enzyme Q10, ubiquinone (CoQ10) may lower blood pressure. CoQ10 use in combination with antihypertensive agents may lead to additional reductions in blood pressure in some individuals. Patients who choose to take CoQ10 concurrently with antihypertensive medications should receive periodic blood pressure monitoring. Patients should be advised to inform their prescriber of their use of CoQ10.
Colchicine: (Major) Due to the risk for serious colchicine toxicity including multi-organ failure and death, avoid coadministration of colchicine and verapamil in patients with normal renal and hepatic function unless the use of both agents is imperative. Coadministration is contraindicated in patients with renal or hepatic impairment because colchicine accumulation may be greater in these populations. Verapamil can inhibit colchicine's metabolism via P-glycoprotein (P-gp) and CYP3A4, resulting in increased colchicine exposure. If coadministration in patients with normal renal and hepatic function cannot be avoided, adjust the dose of colchicine by either reducing the daily dose or the dosage frequency, and carefully monitor for colchicine toxicity. Specific dosage adjustment recommendations are available for the Colcrys product for patients who have taken a P-gp and moderate CYP3A4 inhibitor like verapamil in the past 14 days or require concurrent use: for prophylaxis of gout flares, if the original dose is 0.6 mg twice daily, decrease to 0.3 mg once daily or if the original dose is 0.6 mg once daily, decrease to 0.3 mg once every other day; for treatment of gout flares, give 0.6 mg as a single dose, then 0.3 mg 1 hour later, and do not repeat for at least 3 days; for familial Mediterranean fever, do not exceed a 0.6 mg/day.
Colesevelam: (Moderate) Colesevelam may significantly decrease the Cmax and AUC of sustained-release verapamil. The clinical significance of this interaction is not known since verapamil bioavailability is highly variable.
Conivaptan: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with conivaptan. Coadministration may increase the exposure of verapamil. Conivaptan is a moderate inhibitor of CYP3A; verapamil is a substrate of CYP3A.
Conjugated Estrogens: (Minor) Estrogens are partially metabolized by CYP3A4. Drugs that inhibit CYP3A4 such as verapamil may increase plasma concentrations of estrogens and cause estrogen-related side effects such as nausea and breast tenderness. Patients receiving estrogens should be monitored for an increase in adverse events.
Conjugated Estrogens; Bazedoxifene: (Minor) Estrogens are partially metabolized by CYP3A4. Drugs that inhibit CYP3A4 such as verapamil may increase plasma concentrations of estrogens and cause estrogen-related side effects such as nausea and breast tenderness. Patients receiving estrogens should be monitored for an increase in adverse events.
Conjugated Estrogens; Medroxyprogesterone: (Minor) Estrogens are partially metabolized by CYP3A4. Drugs that inhibit CYP3A4 such as verapamil may increase plasma concentrations of estrogens and cause estrogen-related side effects such as nausea and breast tenderness. Patients receiving estrogens should be monitored for an increase in adverse events.
Crizotinib: (Major) Avoid coadministration of crizotinib with agents known to cause bradycardia, such as verapamil, to the extent possible due to the risk of additive bradycardia; increased exposure to both drugs may also occur. If concomitant use is unavoidable, monitor heart rate and blood pressure regularly, and watch for an increase in crizotinib-related adverse reactions. An interruption of crizotinib therapy or dose adjustment may be necessary if bradycardia occurs. Crizotinib and verapamil are both CYP3A substrates and moderate inhibitors.
Cyclobenzaprine: (Moderate) If concomitant treatment with cyclobenzaprine and verapamil is clinically warranted, careful observation is advised, particularly during treatment initiation or dose increases, due to the potential risk of serotonin syndrome. Discontinue all serotonergic agents and initiate supportive symptomatic treatment if serotonin syndrome occurs.
Cyclophosphamide: (Moderate) Closely monitor complete blood counts if coadministration of cyclophosphamide with angiotensin-converting enzyme inhibitors (ACE inhibitors) is necessary as there is an increased risk of hematologic toxicity (specifically leukopenia) and immunosuppression.
Cyclosporine: (Moderate) Coadministration of verapamil with cyclosporine can lead to increased cyclosporine concentrations and toxicity. Verapamil inhibits CYP3A4 metabolism and thereby can increase the serum concentrations of cyclosporine. Verapamil should be used cautiously in patients stabilized on cyclosporine; cyclosporine dosage reduction may be required. (Moderate) Several cases of acute renal failure have been associated with the addition of angiotensin-converting enzyme (ACE) inhibitors to cyclosporine therapy in renal transplant patients. In response to cyclosporine-induced renal afferent vasoconstriction and glomerular hypoperfusion, angiotensin II is required to maintain an adequate glomerular filtration rate. Inhibition of ACE could reduce renal function acutely. Also, cyclosporine can cause hyperkalemia, and inhibition of angiotensin II leads to reduced aldosterone concentrations, which can increase the serum potassium concentration. Closely monitor renal function and serum potassium concentrations in patients receiving cyclosporine concurrently with ACE inhibitors or potassium salts.
Dabigatran: (Moderate) Increased serum concentrations of dabigatran are possible when dabigatran, a P-glycoprotein (P-gp) substrate, is coadministered with verapamil, a P-gp inhibitor. Patients should be monitored for increased adverse effects of dabigatran while taking products containing verapamil including trandolapril; verapamil. When dabigatran is administered for treatment or reduction in risk of recurrence of deep venous thrombosis (DVT) or pulmonary embolism (PE) or prophylaxis of DVT or PE following hip replacement surgery, avoid coadministration with P-gp inhibitors like verapamil in patients with CrCl less than 50 mL/minute. When dabigatran is used in patients with non-valvular atrial fibrillation and severe renal impairment (CrCl less than 30 mL/minute), avoid coadministration with verapamil, as serum concentrations of dabigatran are expected to be higher than when administered to patients with normal renal function. Concomitant administration of verapamil and dabigatran results in an increased Cmax and AUC of dabigatran; the extent depends on the formulation of verapamil and timing of administration. The greatest increase in exposure of dabigatran occurs when verapamil is present in the gut when dabigatran is taken. In a pharmacokinetic study, immediate-release verapamil given 1 hour prior to dabigatran administration produced the greatest increase in exposure. If verapamil is administered 2 hours after dabigatran administration, the increase in AUC is negligible. Data from the RE-LY trial indicate no significant changes in dabigatran trough concentrations were seen in patients who received concomitant therapy with verapamil. P-gp inhibition and renal impairment are the major independent factors that result in increased exposure to dabigatran.
Daclatasvir: (Moderate) Concurrent administration of daclatasvir, a CYP3A4 substrate, with verapamil, a moderate CYP3A4 inhibitor, may increase daclatasvir serum concentrations. In addition, the therapeutic effects of verapamil, a P-glycoprotein (P-gp) substrate, may be increased by daclatasvir, a P-gp inhibitor. If these drugs are administered together, monitor patients for adverse effects, such as hypotension, headache, fatigue, nausea, and diarrhea. The manufacturer does not recommend daclatasvir dose reduction for adverse reactions.
Danazol: (Minor) Danazol is a CYP3A4 inhibitor and can decrease the hepatic metabolism of CYP3A4 substrates like calcium-channel blockers.
Dantrolene: (Moderate) Concurrent use with skeletal muscle relaxants and antihypertensive agents may result in additive hypotension. Dosage adjustments of the antihypertensive medication may be required.
Dapagliflozin; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Dapagliflozin; Saxagliptin: (Minor) Saxagliptin plasma concentrations are expected to increase in the presence of moderate CYP 3A4/5 inhibitors such as verapamil, but saxagliptin dose adjustment is not advised.
Daridorexant: (Major) Limit the daridorexant dose to 25 mg if coadministered with verapamil. Concomitant use may increase daridorexant exposure and the risk for daridorexant-related adverse effects. Daridorexant is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Concomitant use of another moderate CYP3A inhibitor increased daridorexant overall exposure 2.4-fold.
Darifenacin: (Moderate) Verapamil is an inhibitor of CYP3A4 isoenzymes. Co-administration with verapamil may lead to an increase in serum levels of drugs that are CYP3A4 substrates, including darifenacin.
Darunavir: (Moderate) As darunavir is a CYP3A substrate and inhibitor, interactions with calcium-channel blockers may occur. Complex interactions can be expected with coadministered with diltiazem or verapamil, as both are substrates and inhibitors of CYP3A4.
Darunavir; Cobicistat: (Moderate) As darunavir is a CYP3A substrate and inhibitor, interactions with calcium-channel blockers may occur. Complex interactions can be expected with coadministered with diltiazem or verapamil, as both are substrates and inhibitors of CYP3A4. (Moderate) Coadministration of cobicistat (a strong CYP3A4 inhibitor) with calcium-channel blockers metabolized by CYP3A4, such as verapamil, may result in elevated calcium-channel blockers serum concentrations. If used concurrently, close clinical monitoring with appropriate dose reductions are advised.
Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Moderate) As darunavir is a CYP3A substrate and inhibitor, interactions with calcium-channel blockers may occur. Complex interactions can be expected with coadministered with diltiazem or verapamil, as both are substrates and inhibitors of CYP3A4. (Moderate) Coadministration of cobicistat (a strong CYP3A4 inhibitor) with calcium-channel blockers metabolized by CYP3A4, such as verapamil, may result in elevated calcium-channel blockers serum concentrations. If used concurrently, close clinical monitoring with appropriate dose reductions are advised. (Moderate) Coadministration of tenofovir alafenamide with verapamil may result in increased plasma concentrations of tenofovir leading to an increase in tenofovir-related adverse effects. Tenofovir alafenamide is a P-gp substrate and verapamil is a P-gp inhibitor.
Deferasirox: (Moderate) Deferasirox inhibits CYP2C8. Verapamil is a substrate for CYP2C8. The concomitant administration of deferasirox and the CYP2C8 substrate repaglinide (single dose of 0.5 mg) resulted in an increase in repaglinide Cmax by 62% and an increase in AUC 2.3-fold. Although specific drug interaction studies of deferasirox and verapamil are not available, a similar interaction may occur. The dose of verapamil may need to be decreased if coadministered with deferasirox.
Deflazacort: (Major) Decrease deflazacort dose to one third of the recommended dosage when coadministered with verapamil. Concurrent use may significantly increase conc entrations of 21-desDFZ, the active metabolite of deflazacort, resulting in an increased risk of toxicity. Deflazacort is a CYP3A4 substrate; verapamil is a moderate inhibitor of CYP3A4. Administration of deflazacort with clarithromycin, a strong CYP3A4 inhibitor, increased total exposure to 21-desDFZ by about 3-fold.
Degarelix: (Major) Avoid coadministration of degarelix with verapamil due to the risk of reduced efficacy of degarelix. Verapamil can cause hyperprolactinemia, which reduces the number of pituitary gonadotropin releasing hormone (GnRH) receptors; degarelix is a GnRH analog.
Delavirdine: (Moderate) Delavirdine is a potent inhibitor of the CYP3A4 and increased plasma concentrations of drugs extensively metabolized by this enzyme, such as verapamil, should be expected with concurrent use of delavirdine.
Desloratadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Desogestrel; Ethinyl Estradiol: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Dexbrompheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Dexmedetomidine: (Moderate) Concomitant administration of dexmedetomidine and calcium-channel blockers could lead to additive hypotension and bradycardia; use together with caution. Dexmedetomidine can produce bradycardia or AV block and should be used cautiously in patients who are receiving antihypertensive drugs that may lower the heart rate such as calcium-channel blockers.
Dextromethorphan; Diphenhydramine; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Dextromethorphan; Quinidine: (Major) Pharmacokinetic and pharmacodynamic interactions exist between quinidine and verapamil. Oral verapamil has been shown to reduce the clearance and metabolism of oral quinidine. Quinidine half-life increased and plasma concentrations were higher after verapamil. No changes in quinidine protein binding were observed. In addition to the pharmacokinetic interaction which may potentiate quinidine's clinical effects, both quinidine and verapamil can cause hypotension. When quinidine and verapamil are coadministered in doses that are each well tolerated as monotherapy, hypotension attributable to additive peripheral (alpha)-blockade is sometimes reported. Concurrent use of verapamil and quinidine in patients with hypertrophic cardiomyopathy or arrhythmias can cause significant hypotension. It is recommended to avoid combined therapy with verapamil and quinidine in patients with hypertrophic cardiomyopathy. Quinidine and verapamil may also have additive negative inotropic effects. Concurrent use of verapamil and quinidine should be monitored carefully for electrophysiologic and hemodynamic effects. (Moderate) Quinidine can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents due to the potential for additive hypotension.
Diazepam: (Moderate) Monitor for an increase in diazepam-related adverse reactions, including sedation and respiratory depression, if coadministration with verapamil is necessary. Concurrent use may increase diazepam exposure. Diazepam is a CYP3A4 substrate and verapamil is a CYP3A4 inhibitor.
Diazoxide: (Moderate) Additive hypotensive effects can occur with the concomitant administration of diazoxide with other antihypertensive agents. This interaction can be therapeutically advantageous, but dosages must be adjusted accordingly. The manufacturer advises that IV diazoxide should not be administered to patients within 6 hours of receiving other antihypertensive agents. (Moderate) Additive hypotensive effects can occur with the concomitant administration of diazoxide with other antihypertensive agents. This interaction can be therapeutically advantageous, but dosages must be adjusted accordingly. The manufacturer advises that IV diazoxide should not be administered to patients within 6 hours of receiving other antihypertensive agents.
Diclofenac: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Diclofenac; Misoprostol: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Dienogest; Estradiol valerate: (Minor) Verapamil inhibits CYP3A4 activity. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when verapamil is coadministered with either estrogens or combined hormonal contraceptives.
Diethylpropion: (Major) Diethylpropion has vasopressor effects and may limit the benefit of angiotensin-converting enzyme inhibitors. Although leading drug interaction texts differ in the potential for an interaction between diethylpropion and this group of antihypertensive agents, these effects are likely to be clinically significant and have been described in hypertensive patients on these medications. (Major) Diethylpropion has vasopressor effects and may limit the benefit of calcium-channel blockers. Although leading drug interaction texts differ in the potential for an interaction between diethylpropion and this group of antihypertensive agents, these effects are likely to be clinically significant and have been described in hypertensive patients on these medications.
Diflunisal: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Digoxin: (Major) Consider an empiric digoxin dosage reduction when used with verapamil. Follow digoxin concentrations closely and monitor for signs and symptoms of digoxin toxicity. Concomitant use may increase digoxin exposure and the risk for digoxin related adverse effects. The risk for bradycardia and hypotension may also increase. Chronic verapamil treatment has been observed to increase digoxin levels by 50% to 75% during the first week of digoxin therapy. Digoxin is a P-gp substrate and verapamil is a P-gp inhibitor. (Moderate) Caution should be exercised when administering digoxin with drugs that may cause a significant deterioration in renal function including angiotensin-converting enzyme inhibitors (ACE inhibitors). A decline in glomerular filtration or tubular secretion may impair the excretion of digoxin. Close monitoring of serum digoxin concentrations is essential to avoid enhanced toxicity.
Diphenhydramine; Ibuprofen: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Diphenhydramine; Naproxen: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Diphenhydramine; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Disopyramide: (Contraindicated) Disopyramide and verapamil should not be used concomitantly due to potential for additive negative inotropic effects which could result in left ventricular impairment. Avoid disopyramide administration within 48 hours before or 24 hours after verapamil administration. In addition, verapamil can theoretically inhibit the CYP3A4 metabolism of disopyramide.
Dofetilide: (Contraindicated) The concomitant use of verapamil (CYP3A4 inhibitor) and dofetilide is contraindicated. Coadministration of dofetilide with verapamil increased dofetilide peak plasma concentrations by 42%, although the overall exposure to dofetilide was not significantly increased. Concurrent use of verapamil and dofetilide was also associated with a higher occurrence of torsade de pointes in dofetilide clinical trials.
Dolasetron: (Major) Use caution and monitor ECG if a drug known to prolong the PR interval (e.g., verapamil) is combined with dolasetron. Dolasetron has been associated with a dose-dependent prolongation in the QT, PR, and QRS intervals on an electrocardiogram. Concurrent use may result in additive effects.
Dolutegravir; Rilpivirine: (Moderate) Close clinical monitoring is advised when administering verapamil with rilpivirine due to an increased potential for rilpivirine-related adverse events. Although this interaction has not been studied, predictions can be made based on metabolic pathways. Verapamil is an inhibitor of the hepatic isoenzyme CYP3A4; rilpivirine is metabolized by this isoenzyme. Coadministration may result in increased rilpivirine plasma concentrations.
Donepezil: (Minor) Verapamil may inhibit the metabolism of donepezil by inhibiting CYP3A4. The clinical effect of this interaction on the response to donepezil has not been determined.
Donepezil; Memantine: (Minor) Verapamil may inhibit the metabolism of donepezil by inhibiting CYP3A4. The clinical effect of this interaction on the response to donepezil has not been determined.
Doravirine; Lamivudine; Tenofovir disoproxil fumarate: (Moderate) Coadministration of tenofovir disoproxil fumarate with verapamil may result in increased plasma concentrations of tenofovir, leading to an increase in tenofovir-related adverse effects. Tenofovir disoproxil fumarate is a P-gp substrate and verapamil is a P-gp inhibitor.
Dorzolamide; Timolol: (Moderate) Use verapamil and timolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Doxazosin: (Moderate) Monitor blood pressure if verapamil is used with other antihypertensive agents; an additive blood pressure lowering effect may occur. Using verapamil with agents that attenuate alpha-adrenergic function, such as doxazosin, may result in blood pressure reductions that are excessive in some patients.
Doxercalciferol: (Moderate) Cytochrome P450 enzyme inhibitors, such as verapamil, may inhibit the 25-hydroxylation of doxercalciferol, thereby decreasing the formation of the active metabolite and thus, decreasing efficacy.
Doxorubicin Liposomal: (Major) Avoid the concomitant use of doxorubicin and verapamil; use of these drugs together may increase doxorubicin concentrations and increase the risk of doxorubicin-induced toxicity. Doxorubicin is a substrate of CYP3A4 and P-glycoprotein (P-gp); verapamil is a substrate and inhibitor of CYP3A4 and P-gp.
Doxorubicin: (Major) Avoid the concomitant use of doxorubicin and verapamil; use of these drugs together may increase doxorubicin concentrations and increase the risk of doxorubicin-induced toxicity. Doxorubicin is a substrate of CYP3A4 and P-glycoprotein (P-gp); verapamil is a substrate and inhibitor of CYP3A4 and P-gp.
Dronabinol: (Moderate) Use caution if coadministration of dronabinol with verapamil is necessary, and monitor for an increase in dronabinol-related adverse reactions (e.g., feeling high, dizziness, confusion, somnolence). Dronabinol is a CYP2C9 and 3A4 substrate; verapamil is a moderate inhibitor of CYP3A4. Concomitant use may result in elevated plasma concentrations of dronabinol.
Dronedarone: (Major) If coadministered with dronedarone, initiate verapamil at a low dose and increase only after ECG verification of good tolerability. Both verapamil and dronedarone are substrates and moderate CYP3A4 inhibitors; increased exposure to both drugs may occur. Additionally, the conduction effects of dronedarone may be potentiated by concurrent use of calcium channel blockers with depressant effects on the sinus and AV nodes.
Drospirenone: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of ACE inhibitors may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if an Angiotensin-Converting Enzyme inhibitor (ACE inhibitor) is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
Drospirenone; Estetrol: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of ACE inhibitors may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if an Angiotensin-Converting Enzyme inhibitor (ACE inhibitor) is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
Drospirenone; Estradiol: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of ACE inhibitors may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if an Angiotensin-Converting Enzyme inhibitor (ACE inhibitor) is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. (Minor) Verapamil inhibits CYP3A4 activity. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when verapamil is coadministered with either estrogens or combined hormonal contraceptives.
Drospirenone; Ethinyl Estradiol: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of ACE inhibitors may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if an Angiotensin-Converting Enzyme inhibitor (ACE inhibitor) is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Drospirenone; Ethinyl Estradiol; Levomefolate: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of ACE inhibitors may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if an Angiotensin-Converting Enzyme inhibitor (ACE inhibitor) is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Duloxetine: (Moderate) Orthostatic hypotension and syncope have been reported during duloxetine administration. The concurrent administration of antihypertensive agents and duloxetine may increase the risk of hypotension. Monitor blood pressure if the combination is necessary.
Dutasteride; Tamsulosin: (Moderate) The concomitant administration of tamsulosin with other antihypertensive agents can cause additive hypotensive effects. In addition, diltiazem, nicardipine, and verapamil may increase tamsulosin plasma concentrations via CYP3A4 inhibition. This interaction can be therapeutically advantageous, but dosages must be adjusted accordingly.
Duvelisib: (Moderate) Monitor for increased toxicity of duvelisib and verapamil during coadministration. Coadministration may increase the exposure of both drugs. Duvelisib is a substrate and moderate inhibitor of CYP3A; verapamil is also a substrate and moderate inhibitor of CYP3A.
Edoxaban: (Major) Reduce the dose of edoxaban to 30 mg/day PO in patients being treated for deep venous thrombosis (DVT) or pulmonary embolism and receiving concomitant therapy with verapamil. No dosage adjustment is required in patients with atrial fibrillation. Edoxaban is a P-glycoprotein (P-gp) substrate and verapamil is a P-gp inhibitor. Increased concentrations of edoxaban may occur during concomitant use of verapamil; monitor for increased adverse effects of edoxaban.
Efavirenz: (Moderate) Use caution and careful monitoring when coadministering efavirenz with calcium-channel blockers; efavirenz induces CYP3A4, potentially altering serum concentrations of drugs metabolized by this enzyme such as some calcium-channel blockers. When coadministered, efavirenz decreases the concentrations of diltiazem (decrease in Cmax by 60%, in AUC by 69%, and in Cmin by 63%) and its active metabolites, desacetyl diltiazem and N-monodesmethyl diltiazem; dose adjustments should be made for diltiazem based on clinical response. No data are available regarding coadministration of efavirenz with other calcium channel blockers that are CYP3A4 substrates (e.g., felodipine, nicardipine, and verapamil); as with diltiazem, calcium-channel blocker doses should be adjusted based on clinical response.
Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Coadministration of tenofovir disoproxil fumarate with verapamil may result in increased plasma concentrations of tenofovir, leading to an increase in tenofovir-related adverse effects. Tenofovir disoproxil fumarate is a P-gp substrate and verapamil is a P-gp inhibitor. (Moderate) Use caution and careful monitoring when coadministering efavirenz with calcium-channel blockers; efavirenz induces CYP3A4, potentially altering serum concentrations of drugs metabolized by this enzyme such as some calcium-channel blockers. When coadministered, efavirenz decreases the concentrations of diltiazem (decrease in Cmax by 60%, in AUC by 69%, and in Cmin by 63%) and its active metabolites, desacetyl diltiazem and N-monodesmethyl diltiazem; dose adjustments should be made for diltiazem based on clinical response. No data are available regarding coadministration of efavirenz with other calcium channel blockers that are CYP3A4 substrates (e.g., felodipine, nicardipine, and verapamil); as with diltiazem, calcium-channel blocker doses should be adjusted based on clinical response.
Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Coadministration of tenofovir disoproxil fumarate with verapamil may result in increased plasma concentrations of tenofovir, leading to an increase in tenofovir-related adverse effects. Tenofovir disoproxil fumarate is a P-gp substrate and verapamil is a P-gp inhibitor. (Moderate) Use caution and careful monitoring when coadministering efavirenz with calcium-channel blockers; efavirenz induces CYP3A4, potentially altering serum concentrations of drugs metabolized by this enzyme such as some calcium-channel blockers. When coadministered, efavirenz decreases the concentrations of diltiazem (decrease in Cmax by 60%, in AUC by 69%, and in Cmin by 63%) and its active metabolites, desacetyl diltiazem and N-monodesmethyl diltiazem; dose adjustments should be made for diltiazem based on clinical response. No data are available regarding coadministration of efavirenz with other calcium channel blockers that are CYP3A4 substrates (e.g., felodipine, nicardipine, and verapamil); as with diltiazem, calcium-channel blocker doses should be adjusted based on clinical response.
Elacestrant: (Major) Avoid concomitant use of elacestrant and verapamil due to the risk of increased elacestrant exposure which may increase the risk for adverse effects. Elacestrant is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Concomitant use with another moderate CYP3A inhibitor increased elacestrant overall exposure by 2.3-fold.
Elagolix; Estradiol; Norethindrone acetate: (Minor) Verapamil inhibits CYP3A4 activity. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when verapamil is coadministered with either estrogens or combined hormonal contraceptives.
Elbasvir; Grazoprevir: (Moderate) Administering elbasvir; grazoprevir with verapamil may cause the plasma concentrations of all three drugs to increase; thereby increasing the potential for adverse effects (i.e., elevated ALT concentrations and hepatotoxicity). Verapamil is a substrate and moderate inhibitor of CYP3A. Both elbasvir and grazoprevir are metabolized by CYP3A, and grazoprevir is also a weak CYP3A inhibitor. If these drugs are used together, closely monitor for signs of hepatotoxicity.
Eletriptan: (Moderate) Monitor for increased eletriptan-related adverse effects if coadministered with verapamil. Systemic concentrations of eletriptan may be increased. Eletriptan is a substrate for CYP3A, and verapamil is a moderate CYP3A inhibitor. Coadministration of other moderate CYP3A inhibitors increased the eletriptan AUC by 2 to 4-fold.
Elexacaftor; tezacaftor; ivacaftor: (Major) Adjust the tezacaftor; ivacaftor dosing schedule when coadministered with verapamil; coadministration may increase tezacaftor; ivacaftor exposure and adverse reactions. When combined, dose 1 tezacaftor; ivacaftor combination tablet every other day in the morning and 1 ivacaftor tablet every other day in the morning on alternate days (i.e., tezacaftor/ivacaftor tablet on Day 1 and ivacaftor tablet on Day 2). The evening dose of ivacaftor should not be taken. Both tezacaftor and ivacaftor are CYP3A substrates (ivacaftor is a sensitive substrate); verapamil is a moderate CYP3A inhibitor. Coadministration of a moderate CYP3A inhibitor increased ivacaftor exposure 3-fold. Simulation suggests a moderate inhibitor may increase tezacaftor exposure 2-fold. (Major) If verapamil and ivacaftor are taken together, administer ivacaftor at the usual recommended dose but reduce the frequency to once daily. Coadministration is not recommended in patients younger than 6 months. Ivacaftor is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased ivacaftor exposure by 3-fold. (Major) Reduce the dosing frequency of elexacaftor; tezacaftor; ivacaftor to every other day in the morning when coadministered with verapamil; omit the ivacaftor evening dose and administer in the morning every other day alternating with elexacaftor; tezacaftor; ivacaftor (i.e., recommended dose of elexacaftor; tezacaftor; ivacaftor on day 1 in the morning and recommended dose of ivacaftor on day 2 in the morning). Coadministration may increase elexacaftor; tezacaftor; ivacaftor exposure and adverse reactions. Elexacaftor, tezacaftor, and ivacaftor are CYP3A substrates; verapamil is a moderate CYP3A inhibitor. Coadministration of a moderate CYP3A inhibitor increased ivacaftor exposure by 2.9-fold. Simulation suggests a moderate inhibitor may increase elexacaftor and tezacaftor exposure by 2.3-fold and 2.1-fold, respectively.
Eliglustat: (Major) In intermediate or poor CYP2D6 metabolizers (IMs or PM), coadministration of verapamil (including trandolapril; verapamil) and eliglustat is not recommended. In extensive CYP2D6 metabolizers (EMs), coadministration of these agents requires dosage reduction of eliglustat to 84 mg PO once daily. The coadministration of eliglustat with both verapamil and a moderate or strong CYP2D6 inhibitor is contraindicated in all patients. Verapamil is a moderate CYP3A inhibitor and P-glycoprotein (P-gp) substrate; eliglustat is a CYP3A and CYP2D6 substrate and P-gp inhibitor. Coadministration of eliglustat with CYP3A inhibitors, such as verapamil, may increase eliglustat exposure and the risk of serious adverse events (e.g., QT prolongation and cardiac arrhythmias); this risk is the highest in CYP2D6 IMs and PMs because a larger portion of the eliglustat dose is metabolized via CYP3A. In addition, coadministration of eliglustat with P-gp substrates (e.g., verapamil) may result in increased concentrations of the concomitant drug; monitor patients closely for adverse events, and consider reducing the dosage of verapamil and titrating to clinical effect.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Coadministration of cobicistat (a strong CYP3A4 inhibitor) with calcium-channel blockers metabolized by CYP3A4, such as verapamil, may result in elevated calcium-channel blockers serum concentrations. If used concurrently, close clinical monitoring with appropriate dose reductions are advised. (Moderate) Coadministration of tenofovir alafenamide with verapamil may result in increased plasma concentrations of tenofovir leading to an increase in tenofovir-related adverse effects. Tenofovir alafenamide is a P-gp substrate and verapamil is a P-gp inhibitor.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Coadministration of cobicistat (a strong CYP3A4 inhibitor) with calcium-channel blockers metabolized by CYP3A4, such as verapamil, may result in elevated calcium-channel blockers serum concentrations. If used concurrently, close clinical monitoring with appropriate dose reductions are advised. (Moderate) Coadministration of tenofovir disoproxil fumarate with verapamil may result in increased plasma concentrations of tenofovir, leading to an increase in tenofovir-related adverse effects. Tenofovir disoproxil fumarate is a P-gp substrate and verapamil is a P-gp inhibitor.
Empagliflozin: (Moderate) Administer antidiabetic agents with caution in patients receiving calcium-channel blockers. These drugs may cause hyperglycemia leading to a temporary loss of glycemic control in patients receiving antidiabetic agents. Close observation and monitoring of blood glucose is necessary to maintain adequate glycemic control.
Empagliflozin; Linagliptin: (Moderate) Administer antidiabetic agents with caution in patients receiving calcium-channel blockers. These drugs may cause hyperglycemia leading to a temporary loss of glycemic control in patients receiving antidiabetic agents. Close observation and monitoring of blood glucose is necessary to maintain adequate glycemic control.
Empagliflozin; Linagliptin; Metformin: (Moderate) Administer antidiabetic agents with caution in patients receiving calcium-channel blockers. These drugs may cause hyperglycemia leading to a temporary loss of glycemic control in patients receiving antidiabetic agents. Close observation and monitoring of blood glucose is necessary to maintain adequate glycemic control. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Empagliflozin; Metformin: (Moderate) Administer antidiabetic agents with caution in patients receiving calcium-channel blockers. These drugs may cause hyperglycemia leading to a temporary loss of glycemic control in patients receiving antidiabetic agents. Close observation and monitoring of blood glucose is necessary to maintain adequate glycemic control. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Emtricitabine; Rilpivirine; Tenofovir alafenamide: (Moderate) Close clinical monitoring is advised when administering verapamil with rilpivirine due to an increased potential for rilpivirine-related adverse events. Although this interaction has not been studied, predictions can be made based on metabolic pathways. Verapamil is an inhibitor of the hepatic isoenzyme CYP3A4; rilpivirine is metabolized by this isoenzyme. Coadministration may result in increased rilpivirine plasma concentrations. (Moderate) Coadministration of tenofovir alafenamide with verapamil may result in increased plasma concentrations of tenofovir leading to an increase in tenofovir-related adverse effects. Tenofovir alafenamide is a P-gp substrate and verapamil is a P-gp inhibitor.
Emtricitabine; Rilpivirine; Tenofovir Disoproxil Fumarate: (Moderate) Close clinical monitoring is advised when administering verapamil with rilpivirine due to an increased potential for rilpivirine-related adverse events. Although this interaction has not been studied, predictions can be made based on metabolic pathways. Verapamil is an inhibitor of the hepatic isoenzyme CYP3A4; rilpivirine is metabolized by this isoenzyme. Coadministration may result in increased rilpivirine plasma concentrations. (Moderate) Coadministration of tenofovir disoproxil fumarate with verapamil may result in increased plasma concentrations of tenofovir, leading to an increase in tenofovir-related adverse effects. Tenofovir disoproxil fumarate is a P-gp substrate and verapamil is a P-gp inhibitor.
Emtricitabine; Tenofovir alafenamide: (Moderate) Coadministration of tenofovir alafenamide with verapamil may result in increased plasma concentrations of tenofovir leading to an increase in tenofovir-related adverse effects. Tenofovir alafenamide is a P-gp substrate and verapamil is a P-gp inhibitor.
Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Coadministration of tenofovir disoproxil fumarate with verapamil may result in increased plasma concentrations of tenofovir, leading to an increase in tenofovir-related adverse effects. Tenofovir disoproxil fumarate is a P-gp substrate and verapamil is a P-gp inhibitor.
Encorafenib: (Major) Avoid coadministration of encorafenib and verapamil due to increased encorafenib exposure. If concurrent use cannot be avoided, reduce the encorafenib dose to one-half of the dose used prior to the addition of verapamil. If verapamil is discontinued, the original encorafenib dose may be resumed after 3 to 5 elimination half-lives of verapamil. Encorafenib is a CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. Coadministration of a moderate CYP3A4 inhibitor with a single 50 mg dose of encorafenib (0.1 times the recommended dose) increased the encorafenib AUC and Cmax by 2-fold and 45%, respectively.
Entecavir: (Moderate) Because entecavir is primarily eliminated by the kidneys and ACE inhibitors can affect renal function, concurrent administration with ACE inhibitors may increase the serum concentrations of entecavir and adverse events. Monitor for adverse effects when these drugs are coadministered.
Entrectinib: (Major) Avoid coadministration of entrectinib with verapamil due to increased entrectinib exposure resulting in increased treatment-related adverse effects. If coadministration cannot be avoided in adults and pediatric patients 12 years and older with BSA greater than 1.5 m2, reduce the entrectinib dose to 200 mg PO once daily. If verapamil is discontinued, resume the original entrectinib dose after 3 to 5 elimination half-lives of verapamil. Entrectinib is a CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. Coadministration of a moderate CYP3A4 inhibitor is predicted to increase the AUC of entrectinib by 3-fold.
Enzalutamide: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with enzalutamide is necessary. Concomitant use may decrease plasma concentrations of verapamil. Verapamil is a CYP3A4 substrate and enzalutamide is a strong CYP3A4 inducer.
Ephedrine: (Major) The cardiovascular effects of sympathomimetics, such as ephedrine, may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Blood pressure and heart rates should be monitored closely to confirm that the desired antihypertensive effect is achieved. (Major) The cardiovascular effects of sympathomimetics, such as ephedrine, may reduce the antihypertensive effects produced by calcium-channel blockers. Blood pressure and heart rates should be monitored closely to confirm that the desired antihypertensive effect is achieved.
Ephedrine; Guaifenesin: (Major) The cardiovascular effects of sympathomimetics, such as ephedrine, may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Blood pressure and heart rates should be monitored closely to confirm that the desired antihypertensive effect is achieved. (Major) The cardiovascular effects of sympathomimetics, such as ephedrine, may reduce the antihypertensive effects produced by calcium-channel blockers. Blood pressure and heart rates should be monitored closely to confirm that the desired antihypertensive effect is achieved.
Epinephrine: (Moderate) Antihypertensives, including angiotensin-converting enzyme inhibitors, antagonize the vasopressor effects of parenteral epinephrine. (Moderate) Antihypertensives, including calcium-channel blockers, antagonize the vasopressor effects of parenteral epinephrine.
Epirubicin: (Moderate) Close cardiac monitoring is recommended throughout therapy in patients receiving concomitant therapy with epirubicin and calcium-channel blockers. Individuals receiving these medications together are at increased risk of developing heart failure.
Eplerenone: (Major) Do not exceed an eplerenone dose of 25 mg PO once daily if given concurrently with a CYP3A4 inhibitor in a post-myocardial infarction patient with heart failure. In patients with hypertension receiving a concurrent CYP3A4 inhibitor, initiate eplerenone at 25 mg PO once daily; the dose may be increased to a maximum of 25 mg PO twice daily for inadequate blood pressure response. In addition, measure serum creatinine and serum potassium within 3 to 7 days of initiating a CYP3A4 inhibitor and periodically thereafter. Eplerenone is a CYP3A4 substrate. Verapamil is a CYP3A4 inhibitor. Coadministration with moderate CYP3A4 inhibitors increased eplerenone exposure by 100% to 190%. Increased eplerenone concentrations may lead to a risk of developing hyperkalemia and hypotension. (Major) Monitor serum potassium and serum creatinine concentrations within 3 to 7 days of initiating coadministration of eplerenone and angiotensin-converting enzyme (ACE) inhibitors. Hyperkalemia risk is increased when eplerenone is used with ACE inhibitors. Patients who develop hyperkalemia may continue eplerenone with proper dose adjustment; eplerenone dose reduction decreases potassium concentrations.
Epoprostenol: (Moderate) Calcium-channel blockers can have additive hypotensive effects with other antihypertensive agents. This additive effect can be desirable, but the patient should be monitored carefully and the dosage should be adjusted based on clinical response.
Eprosartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Eprosartan; Hydrochlorothiazide, HCTZ: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Ergot alkaloids: (Moderate) Monitor for an increase in ergotamine-related adverse effects and adjust the ergot alkaloid dosage as necessary if concomitant use of verapamil is required. Concomitant use may increase the systemic exposure of ergot alkaloids and increase the risk for adverse reactions such as vasospasm which may lead to cerebral ischemia and ischemia of the extremities. Ergot alkaloids are CYP3A substrates and verapamil is a moderate CYP3A inhibitor.
Ergotamine; Caffeine: (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products to minimize caffeine-related side effects.
Erlotinib: (Major) Avoid coadministration of erlotinib with verapamil if possible due to the increased risk of erlotinib-related adverse reactions. If concomitant use is unavoidable and severe reactions occur, reduce the dose of erlotinib by 50 mg decrements. Erlotinib is primarily metabolized by CYP3A4 and to a lesser extent by CYP1A2. Verapamil is a CYP3A4 and CYP1A2 inhibitor. Coadministration with another moderate CYP3A4/CYP1A2 inhibitor increased erlotinib exposure by 39% and increased the erlotinib Cmax by 17%.
Ertugliflozin; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Erythromycin: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with erythromycin. Coadministration may increase the exposure of verapamil. Erythromycin is a moderate inhibitor of CYP3A4; verapamil is a substrate of CYP3A4.
Esmolol: (Major) Esmolol is contraindicated with intravenous verapamil use in close proximity (within a few hours). Fatal cardiac arrests have occurred in patients receiving esmolol and intravenous verapamil. Use esmolol and oral verapamil with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Estazolam: (Moderate) Verapamil is a CYP3A4 inhibitor and may reduce the metabolism of estazolam and increase the potential for benzodiazepine toxicity.
Esterified Estrogens: (Minor) Estrogens are partially metabolized by CYP3A4. Drugs that inhibit CYP3A4 such as verapamil may increase plasma concentrations of estrogens and cause estrogen-related side effects such as nausea and breast tenderness. Patients receiving estrogens should be monitored for an increase in adverse events.
Esterified Estrogens; Methyltestosterone: (Minor) Estrogens are partially metabolized by CYP3A4. Drugs that inhibit CYP3A4 such as verapamil may increase plasma concentrations of estrogens and cause estrogen-related side effects such as nausea and breast tenderness. Patients receiving estrogens should be monitored for an increase in adverse events.
Estradiol: (Minor) Estrogens can induce fluid retention and may increase blood pressure in some patients; patients who are receiving antihypertensive agents concurrently with hormonal contraceptives should be monitored for antihypertensive effectiveness. (Minor) Verapamil inhibits CYP3A4 activity. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when verapamil is coadministered with either estrogens or combined hormonal contraceptives.
Estradiol; Levonorgestrel: (Minor) Verapamil inhibits CYP3A4 activity. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when verapamil is coadministered with either estrogens or combined hormonal contraceptives.
Estradiol; Norethindrone: (Minor) Verapamil inhibits CYP3A4 activity. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when verapamil is coadministered with either estrogens or combined hormonal contraceptives.
Estradiol; Norgestimate: (Minor) Verapamil inhibits CYP3A4 activity. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when verapamil is coadministered with either estrogens or combined hormonal contraceptives.
Estradiol; Progesterone: (Minor) The metabolism of progesterone may be inhibited by verapamil, an inhibitor of cytochrome P450 3A4 hepatic enzymes. (Minor) Verapamil inhibits CYP3A4 activity. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when verapamil is coadministered with either estrogens or combined hormonal contraceptives.
Estropipate: (Minor) Estrogens are partially metabolized by CYP3A4. Drugs that inhibit CYP3A4 such as verapamil may increase plasma concentrations of estrogens and cause estrogen-related side effects such as nausea and breast tenderness. Patients receiving estrogens should be monitored for an increase in adverse events.
Ethanol: (Major) Advise patients to avoid alcohol and alcohol-containing products while taking verapamil. Verapamil has been found to significantly inhibit alcohol elimination resulting in elevated blood alcohol concentrations that may prolong the intoxicating effects of alcohol. The patient may experience an increase in sedation, dizziness, hypotension, and CNS depression. (Major) Verapamil has been found to significantly inhibit alcohol elimination resulting in elevated blood alcohol concentrations that may prolong the intoxicating effects of alcohol. The patient may experience an increase in sedation, dizziness, hypotension, and CNS depression. Advise the patient to limit alcohol ingestion during verapamil therapy.
Ethinyl Estradiol; Norelgestromin: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Ethinyl Estradiol; Norethindrone Acetate: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Ethinyl Estradiol; Norgestrel: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Ethiodized Oil: (Moderate) Because the use of other nephrotoxic drugs, including ACE inhibitors, is an additive risk factor for nephrotoxicity in patients receiving radiopaque contrast agents, ACE inhibitor therapy should be withheld, when possible, during radiopaque contrast agent administration.
Ethosuximide: (Moderate) Verapamil is an inhibitor of CYP3A4 isoenzymes. Co-administration with verapamil may lead to an increase in serum levels of drugs that are CYP3A4 substrates including ethosuximide.
Ethynodiol Diacetate; Ethinyl Estradiol: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Etodolac: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Etomidate: (Major) The depression of cardiac contractility, conductivity, and automaticity as well as the vascular dilation associated with general anesthetics may be potentiated by calcium-channel blockers. Alternatively, general anesthetics can potentiate the hypotensive effects of calcium-channel blockers. When used concomitantly, anesthetics and calcium-channel blockers should be titrated carefully to avoid excessive cardiovascular depression. (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Etonogestrel: (Minor) Coadministration of etonogestrel and moderate CYP3A4 inhibitors such as verapamil may increase the serum concentration of etonogestrel.
Etonogestrel; Ethinyl Estradiol: (Minor) Coadministration of etonogestrel and moderate CYP3A4 inhibitors such as verapamil may increase the serum concentration of etonogestrel. (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Etravirine: (Moderate) Monitor for an increase in etravirine-related adverse reactions and decreased verapamil efficacy if concomitant use is necessary. The exposure of both drugs may be altered. Etravirine is a CYP3A substrate and moderate CYP3A inducer and verapamil is a CYP3A substrate and moderate CYP3A inhibitor.
Everolimus: (Major) Avoid coadministration of everolimus with angiotensin-converting enzyme inhibitors (ACE inhibitors) as the risk of angioedema, with or without respiratory impairment, may be increased. In a pooled analysis of randomized, double-blind oncology clinical trials, angioedema was reported in 6.8% of patients receiving concomitant everolimus and ACE inhibitor therapy, compared to 1.3% of patients with an ACE inhibitor alone. (Major) Coadministration of everolimus with verapamil requires a dose reduction for some indications and close monitoring for others. For patients with oncology indications and tuberous sclerosis complex (TSC)-associated renal angiomyolipoma, reduce the initial dose of everolimus to 2.5 mg PO once daily; the dose may be increased to 5 mg PO once daily if the 2.5 mg dose is tolerated. For patients with TSC-associated subependymal giant cell astrocytoma (SEGA) and TSC-associated partial-onset seizures, reduce the daily dose of everolimus by 50%, changing to every-other-day dosing if the reduced dose is lower than the lowest available strength; assess the everolimus whole blood trough concentration 2 weeks after initiation of verapamil and adjust the dose as necessary to remain in the recommended therapeutic range. Also monitor everolimus whole blood trough concentrations for patients receiving everolimus for either kidney or liver transplant and adjust the dose as necessary to remain in the recommended therapeutic range. Everolimus is a sensitive CYP3A4 substrate and a P-glycoprotein (P-gp) substrate. Verapamil is a moderate CYP3A4 and P-gp inhibitor. Coadministration with verapamil increased the Cmax and AUC of everolimus by 2.3-fold and 3.5-fold, respectively.
Ezetimibe; Simvastatin: (Major) Do not exceed a simvastatin dose of 10 mg/day in patients taking verapamil due to increased risk of myopathy, including rhabdomyolysis. For patients chronically receiving simvastatin 80 mg/day who need to be started on verapamil, consider switching to an alternative statin with less potential for interaction. Carefully weigh the benefits of combined use of verapamil and simvastatin against the potential risks. Verapamil increases the simvastatin exposure by approximately 2-fold. The interaction is presumed due to increased simvastatin bioavailability via inhibition of CYP3A metabolism and reduction of first-pass metabolism by verapamil.
Fedratinib: (Moderate) Monitor for increased toxicity of verapamil during coadministration as fedratinib may increase verapamil exposure. Fedratinib is a moderate inhibitor of CYP3A; verapamil is a substrate of CYP3A.
Fenoprofen: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Fentanyl: (Moderate) Consider a reduced dose of fentanyl with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. If verapamil is discontinued, consider increasing the fentanyl dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Fentanyl is a CYP3A4 substrate, and coadministration with CYP3A4 inhibitors like verapamil can increase fentanyl exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of fentanyl. If verapamil is discontinued, fentanyl plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to fentanyl.
Fexofenadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Fezolinetant: (Contraindicated) Concomitant use of fezolinetant and verapamil is contraindicated due to the risk of increased fezolinetant exposure which may increase the risk of fezolinetant-related adverse effects. Fezolinetant is a CYP1A2 substrate; verapamil is a weak CYP1A2 inhibitor. Concomitant use with another weak CYP1A2 inhibitor increased fezolinetant overall exposure by 100%.
Finasteride; Tadalafil: (Moderate) Monitor for an increase in tadalafil-related adverse reactions if coadministration with verapamil is necessary. Tadalafil is a CYP3A4 substrate and verapamil is a moderate CYP3A inhibitor. Although specific interactions have not been studied, moderate CYP3A4 inhibitors would likely increase tadalafil exposure.
Finerenone: (Moderate) Monitor serum potassium concentrations closely if finerenone and angiotensin-converting enzyme inhibitors (ACEI) are used together. Concomitant use may increase the risk of hyperkalemia. (Moderate) Monitor serum potassium during initiation or dose adjustment of either finerenone or verapamil; a finerenone dosage reduction may be necessary. Concomitant use may increase finerenone exposure and the risk of hyperkalemia. Finerenone is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased overall exposure to finerenone by 248%.
Fingolimod: (Major) If possible, do not start fingolimod in a patient who is taking a drug that slows the heart rate or atrioventricular conduction such as verapamil. Use of these drugs during fingolimod initiation may be associated with severe bradycardia or heart block. Seek advice from the prescribing physician regarding the possibility to switch to drugs that do not slow the heart rate or atrioventricular conduction before initiating fingolimod. After the first fingolimod dose, overnight monitoring with continuous ECG in a medical facility is advised for patients who cannot stop taking drugs that slow the heart rate or atrioventricular conduction. Experience with fingolimod in patients receiving concurrent therapy with drugs that slow the heart rate or atrioventricular conduction is limited.
Fish Oil, Omega-3 Fatty Acids (Dietary Supplements): (Moderate) High doses of fish oil supplements may produce a blood pressure lowering effect. It is possible that additive reductions in blood pressure may be seen when fish oils are used in a patient already taking antihypertensive agents.
Flecainide: (Moderate) Limit use of flecainide and verapamil when possible, and do not exceed maximum daily doses. Coadministration of flecainide with verapamil increases the risk of bradycardia, AV block, and hypotension.
Flibanserin: (Contraindicated) The concomitant use of flibanserin and moderate CYP3A4 inhibitors, such as verapamil, is contraindicated. Moderate CYP3A4 inhibitors can increase flibanserin concentrations, which can cause s evere hypotension and syncope. If initiating flibanserin following use of a moderate CYP3A4 inhibitor, start flibanserin at least 2 weeks after the last dose of the CYP3A4 inhibitor. If initiating a moderate CYP3A4 inhibitor following flibanserin use, start the moderate CYP3A4 inhibitor at least 2 days after the last dose of flibanserin.
Fluconazole: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with fluconazole. Coadministration may increase the exposure of verapamil. Verapamil is a substrate of CYP3A and fluconazole is a moderate CYP3A inhibitor.
Fluorescein: (Moderate) Patients on angiotensin-converting enzyme inhibitors are at an increased risk of adverse reactions when administered fluorescein injection. If fluorescein injection is deemed necessary in a patient on ACE inhibitor therapy, monitor as appropriate during and after the procedure.
Flurazepam: (Moderate) CYP3A4 inhibitors, such as verapamil, may reduce the metabolism of flurazepam and increase the potential for benzodiazepine toxicity.
Flurbiprofen: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Fluticasone; Umeclidinium; Vilanterol: (Moderate) Umeclidinium is a P-gp substrate. When verapamil, a moderate P-gp transporter inhibitor, was given to healthy adult subjects at a dose of 240 mg once daily in combination with umeclidinium, no effect on umeclidinium Cmax was observed. However, an approximately 1.4-fold increase in umeclidinium AUC was observed.
Fluvoxamine: (Moderate) Certain SSRIs, including fluvoxamine, are inhibitors of CYP3A4, and may theoretically increase verapamil serum concentrations.
Fosamprenavir: (Moderate) Monitor blood pressure, heart rate, and for increased fosamprenavir-related adverse reactions during coadministration of verapamil with fosamprenavir. Concomitant use may increase the exposure of both drugs. Verapamil and fosamprenavir are both CYP3A substrates and moderate CYP3A inhibitors.
General anesthetics: (Major) The depression of cardiac contractility, conductivity, and automaticity as well as the vascular dilation associated with general anesthetics may be potentiated by calcium-channel blockers. Alternatively, general anesthetics can potentiate the hypotensive effects of calcium-channel blockers. When used concomitantly, anesthetics and calcium-channel blockers should be titrated carefully to avoid excessive cardiovascular depression. (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Ginger, Zingiber officinale: (Minor) In vitro studies have demonstrated the positive inotropic effects of ginger, Zingiber officinale. It is theoretically possible that ginger could affect the action of antiarrhythmics, however, no clinical data are available.
Ginkgo, Ginkgo biloba: (Moderate) Ginkgo biloba appears to inhibit the metabolism of calcium-channel blockers, perhaps by inhibiting the CYP3A4 isoenzyme. A non-controlled pharmacokinetic study in healthy volunteers found that the concurrent administration of ginkgo with nifedipine resulted in a 53% increase in nifedipine peak concentrations. More study is needed regarding ginkgo's effects on CYP3A4 and whether clinically significant drug interactions result.
Ginseng, Panax ginseng: (Moderate) Ginseng appears to inhibit the metabolism of calcium-channel blockers, perhaps by inhibiting the CYP3A4 isoenzyme. A non-controlled pharmacokinetic study in healthy volunteers found that the concurrent administration of ginseng with nifedipine resulted in a 30% increase in nifedipine peak concentrations. More study is needed regarding ginseng's effects on CYP3A4 and whether clinically significant drug interactions result.
Glecaprevir; Pibrentasvir: (Moderate) Caution is advised with the coadministration of glecaprevir and verapamil as coadministration may increase serum concentrations of both drugs and increase the risk of adverse effects. Glecaprevir and verapamil are both substrates and inhibitors of P-glycoprotein (P-gp). (Moderate) Caution is advised with the coadministration of pibrentasvir and verapamil as coadministration may increase serum concentrations of both drugs and increase the risk of adverse effects. Pibrentasvir and verapamil are both substrates and inhibitors of P-glycoprotein (P-gp).
Glipizide; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Glyburide; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Gold: (Minor) Nitritoid reactions (facial flushing, diaphoresis, dizziness, nausea/vomiting, hypotension, tachycardia, syncope, and anaphylactic type reactions) or vasomotor reactions have been reported rarely in patients receiving injectable gold and concomitant ACE inhibitor therapy. Monitor closely for nitritoid reactions during co-therapy with gold and ACE inhibitor agents.
Goserelin: (Major) Avoid coadministration of goserelin with verapamil due to the risk of reduced efficacy of goserelin. Verapamil can cause hyperprolactinemia, which reduces the number of pituitary gonadotropin releasing hormone (GnRH) receptors; goserelin is a GnRH analog.
Grapefruit juice: (Major) Grapefruit juice contains an unknown compound that can inhibit the cytochrome P-450 CYP3A4 isozyme in the gut wall. Grapefruit juice can increase the serum concentrations and oral bioavailability of verapamil. Co-administration of oral verapamil with grapefruit juice significantly increases the AUC and peak plasma concentrations of verapamil. It is generally recommended to avoid grapefruit juice during verapamil therapy.
Green Tea: (Minor) Verapamil reduces the clearance of caffeine and increases serum caffeine concentrations, presumably via inhibition of hepatic metabolism. During concomitant therapy with verapamil, it may be prudent to advise patients to limit or minimize the intake of caffeinated products such as green tea.
Guaifenesin; Hydrocodone: (Moderate) Consider a reduced dose of hydrocodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. It is recommended to avoid this combination when hydrocodone is being used for cough. Hydrocodone is a CYP3A4 substrate, and coadministration with CYP3A4 inhibitors like verapamil can increase hydrocodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of hydrocodone. These effects could be more pronounced in patients also receiving a CYP2D6 inhibitor. If verapamil is discontinued, hydrocodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to hydrocodone.
Guaifenesin; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Guanfacine: (Major) Verapamil may significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if these agents are taken together, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available. Monitor patients closely for alpha-adrenergic effects including hypotension, drowsiness, lethargy, and bradycardia. Upon verapamil discontinuation, the guanfacine ER dosage should be increased back to the recommended dose. Guanfacine is primarily metabolized by CYP3A4, and verapamil is a moderate CYP3A4 inhibitor.
Haloperidol: (Moderate) In general, antipsychotics like haloperidol should be used cautiously with antihypertensive agents due to the possibility of additive hypotension. Verapamil is a substrate and inhibitor of CYP3A4. Mild to moderate increases in haloperidol plasma concentrations have been reported during concurrent use of haloperidol and substrates or inhibitors of CYP3A4 or CYP2D6. Elevated haloperidol concentrations occurring through inhibition of CYP2D6 or CYP3A4 may increase the risk of adverse effects, including QT prolongation. (Moderate) In general, haloperidol should be used cautiously with antihypertensive agents due to the possibility of additive hypotension.
Histrelin: (Major) Avoid coadministration of histrelin with verapamil due to the risk of reduced efficacy of histrelin. Verapamil can cause hyperprolactinemia, which reduces the number of pituitary gonadotropin releasing hormone (GnRH) receptors; histrelin is a GnRH analog.
Homatropine; Hydrocodone: (Moderate) Consider a reduced dose of hydrocodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. It is recommended to avoid this combination when hydrocodone is being used for cough. Hydrocodone is a CYP3A4 substrate, and coadministration with CYP3A4 inhibitors like verapamil can increase hydrocodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of hydrocodone. These effects could be more pronounced in patients also receiving a CYP2D6 inhibitor. If verapamil is discontinued, hydrocodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to hydrocodone.
Hydantoins: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with hydantoins is necessary. Concomitant use may decrease plasma concentrations of verapamil. Verapamil is a CYP3A4 substrate and hydantoins are strong CYP3A4 inducers.
Hydralazine; Isosorbide Dinitrate, ISDN: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary. (Moderate) Nitroglycerin can cause hypotension. This action may be additive with other agents that can cause hypotension such as calcium-channel blockers. Patients should be monitored more closely for hypotension if nitroglycerin, including nitroglycerin rectal ointment, is used concurrently with a calcium-channel blocker.
Hydrocodone: (Moderate) Consider a reduced dose of hydrocodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. It is recommended to avoid this combination when hydrocodone is being used for cough. Hydrocodone is a CYP3A4 substrate, and coadministration with CYP3A4 inhibitors like verapamil can increase hydrocodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of hydrocodone. These effects could be more pronounced in patients also receiving a CYP2D6 inhibitor. If verapamil is discontinued, hydrocodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to hydrocodone.
Hydrocodone; Ibuprofen: (Moderate) Consider a reduced dose of hydrocodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. It is recommended to avoid this combination when hydrocodone is being used for cough. Hydrocodone is a CYP3A4 substrate, and coadministration with CYP3A4 inhibitors like verapamil can increase hydrocodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of hydrocodone. These effects could be more pronounced in patients also receiving a CYP2D6 inhibitor. If verapamil is discontinued, hydrocodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to hydrocodone. (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Hydrocodone; Pseudoephedrine: (Moderate) Consider a reduced dose of hydrocodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. It is recommended to avoid this combination when hydrocodone is being used for cough. Hydrocodone is a CYP3A4 substrate, and coadministration with CYP3A4 inhibitors like verapamil can increase hydrocodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of hydrocodone. These effects could be more pronounced in patients also receiving a CYP2D6 inhibitor. If verapamil is discontinued, hydrocodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to hydrocodone. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Ibritumomab Tiuxetan: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
Ibrutinib: (Major) If ibrutinib is coadministered with verapamil, reduce the initial ibrutinib dosage to 280 mg/day PO in patients receiving ibrutinib for B-cell malignancy. Resume ibrutinib at the previous dosage if verapamil is discontinued. No initial ibrutinib dosage adjustment is necessary in patients receiving ibrutinib for chronic graft-versus-host disease. Monitor patients for ibrutinib toxicity (e.g., hematologic toxicity, bleeding, infection); modify the ibrutinib dosage as recommended if toxicity occurs. Ibrutinib is a CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. When ibrutinib was administered with multiple doses of another moderate CYP3A4 inhibitor, the AUC value of ibrutinib was increased by 3-fold.
Ibuprofen: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Ibuprofen; Famotidine: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Ibuprofen; Oxycodone: (Moderate) Consider a reduced dose of oxycodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. If verapamil is discontinued, consider increasing the oxycodone dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Oxycodone is a CYP3A4 substrate, and coadministration with a moderate inhibitor like verapamil can increase oxycodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of oxycodone. If verapamil is discontinued, oxycodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to oxycodone. (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Ibuprofen; Pseudoephedrine: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Icatibant: (Minor) Although clinical data are lacking, icatibant is a bradykinin B2 receptor antagonist and may theoretically potentiate the antihypertensive effect of ACE inhibitors.
Idelalisib: (Major) Avoid concomitant use of idelalisib, a strong CYP3A inhibitor, with verapamil, a CYP3A substrate, as verapamil toxicities may be significantly increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib.
Ifosfamide: (Moderate) Monitor for a decrease in the efficacy of ifosfamide if coadministration with verapamil is necessary. Ifosfamide is metabolized by CYP3A4 to its active alkylating metabolites. Verapamil is a moderate CYP3A4 inhibitor. Coadministration may decrease plasma concentrations of these active metabolites, decreasing the effectiveness of ifosfamide treatment.
Iloperidone: (Moderate) Secondary to alpha-blockade, iloperidone can produce vasodilation that may result in additive effects during concurrent use with antihypertensive agents. The potential reduction in blood pressure can precipitate orthostatic hypotension and associated dizziness, tachycardia, and syncope. If concurrent use of iloperidone and antihypertensive agents is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known.
Iloprost: (Moderate) Calcium-channel blockers can have additive hypotensive effects with other antihypertensive agents. This additive effect can be desirable, but the patient should be monitored carefully and the dosage should be adjusted based on clinical response. (Moderate) Further reductions in blood pressure may occur when inhaled iloprost is administered to patients receiving other antihypertensive agents.
Imatinib: (Moderate) Imatinib is a potent inhibitor of cytochrome P450 3A4 and may increase concentrations of other drugs metabolized by this enzyme including verapamil.
Imipramine: (Moderate) Verapamil inhibits the CYP3A4 metabolism of imipramine and decreases imipramine clearance by 25%. Imipramine serum concentrations are suggested to monitor imipramine therapy when adding verapamil therapy or changing verapamil dosage.
Incretin Mimetics: (Moderate) Monitor blood glucose during concomitant incretin mimetic and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Indacaterol: (Minor) Although no dosage adjustment of the 75 mcg indacaterol daily dose is needed, use caution if indacaterol and verapamil are used concurrently. By inhibiting CYP3A4 and P-gp, verapamil alters indacaterol metabolism. In drug interaction studies, coadministration of indacaterol 300 mcg (single dose) with verapamil (80 mcg 3 times daily for 4 days) resulted in a 2-fold increase in indacaterol AUC (0-24), and 1.5-fold increase in indacaterol Cmax.
Indacaterol; Glycopyrrolate: (Minor) Although no dosage adjustment of the 75 mcg indacaterol daily dose is needed, use caution if indacaterol and verapamil are used concurrently. By inhibiting CYP3A4 and P-gp, verapamil alters indacaterol metabolism. In drug interaction studies, coadministration of indacaterol 300 mcg (single dose) with verapamil (80 mcg 3 times daily for 4 days) resulted in a 2-fold increase in indacaterol AUC (0-24), and 1.5-fold increase in indacaterol Cmax.
Indapamide: (Moderate) The effects of indapamide may be additive when administered with other antihypertensive agents or diuretics. In some patients, this may be desirable, but orthostatic hypotension may occur. Patients with hyponatremia or hypovolemia are more susceptible to developing reversible renal insufficiency when given an angiotensin-converting enzyme inhibitors (ACE Inhibitors) and diuretic therapy concomitantly.
Indinavir: (Moderate) Coadministration of ritonavir with verapamil may increase the serum concentrations of verapamil, potentially resulting in verapamil toxicity. The manufacturer for ritonavir recommends caution when coadministering this combination. A similar effect could be expected with other anti-retroviral protease inhibitors, which are also inhibitors of CYP3A4.
Indomethacin: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Infigratinib: (Major) Avoid concomitant use of infigratinib and verapamil. Coadministration may increase infigratinib exposure, increasing the risk of adverse effects. Infigratinib is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor.
Insulins: (Moderate) Monitor blood glucose during concomitant insulin and angiotensin-converting enzyme (ACE) inhibitor use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Intravenous Lipid Emulsions: (Moderate) High doses of fish oil supplements may produce a blood pressure lowering effect. It is possible that additive reductions in blood pressure may be seen when fish oils are used in a patient already taking antihypertensive agents.
Iodixanol: (Moderate) Because the use of other nephrotoxic drugs, including ACE inhibitors, is an additive risk factor for nephrotoxicity in patients receiving radiopaque contrast agents, ACE inhibitor therapy should be withheld, when possible, during radiopaque contrast agent administration.
Iohexol: (Moderate) Because the use of other nephrotoxic drugs, including ACE inhibitors, is an additive risk factor for nephrotoxicity in patients receiving radiopaque contrast agents, ACE inhibitor therapy should be withheld, when possible, during radiopaque contrast agent administration.
Iomeprol: (Moderate) Because the use of other nephrotoxic drugs, including ACE inhibitors, is an additive risk factor for nephrotoxicity in patients receiving radiopaque contrast agents, ACE inhibitor therapy should be withheld, when possible, during radiopaque contrast agent administration.
Iopamidol: (Moderate) Because the use of other nephrotoxic drugs, including ACE inhibitors, is an additive risk factor for nephrotoxicity in patients receiving radiopaque contrast agents, ACE inhibitor therapy should be withheld, when possible, during radiopaque contrast agent administration.
Iopromide: (Moderate) Because the use of other nephrotoxic drugs, including ACE inhibitors, is an additive risk factor for nephrotoxicity in patients receiving radiopaque contrast agents, ACE inhibitor therapy should be withheld, when possible, during radiopaque contrast agent administration.
Ioversol: (Moderate) Because the use of other nephrotoxic drugs, including ACE inhibitors, is an additive risk factor for nephrotoxicity in patients receiving radiopaque contrast agents, ACE inhibitor therapy should be withheld, when possible, during radiopaque contrast agent administration.
Irbesartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Irbesartan; Hydrochlorothiazide, HCTZ: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Iron Dextran: (Moderate) The concomitant use of angiotensin-converting enzyme inhibitors (ACE inhibitors) with iron dextran may increase the risk for anaphylactic-type reactions. The factors that affect the risk for anaphylactic-type reactions to iron dextran products are not fully known but limited clinical data suggest the risk may be increased among patients with a history of drug allergy or multiple drug allergies. Patients should be monitored for signs and symptoms of anaphylactic-type reactions during all iron dextran administrations.
Isavuconazonium: (Moderate) Concomitant use of isavuconazonium with verapamil may result in increased serum concentrations of both drugs. Verapamil is a substrate and inhibitor of the hepatic isoenzyme CYP3A4 and a substrate of the drug transporter P-glycoprotein (P-gp); isavuconazole, the active moiety of isavuconazonium, is a sensitive substrate and moderate inhibitor of CYP3A4 and an inhibitor of P-gp. Caution and close monitoring are advised if these drugs are used together.
Isocarboxazid: (Moderate) Additive hypotensive effects may be seen when monoamine oxidase inhibitors (MAOIs) are combined with antihypertensives. Careful monitoring of blood pressure is suggested during concurrent therapy of MAOIs with angiotensin-converting enzyme inhibitors (ACE inhibitors). Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider. (Moderate) Additive hypotensive effects may be seen when monoamine oxidase inhibitors (MAOIs) are combined with antihypertensives. Careful monitoring of blood pressure is suggested during concurrent therapy of MAOIs with calcium-channel blockers. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider.
Isoflurane: (Major) The depression of cardiac contractility, conductivity, and automaticity as well as the vascular dilation associated with general anesthetics may be potentiated by calcium-channel blockers. Alternatively, general anesthetics can potentiate the hypotensive effects of calcium-channel blockers. When used concomitantly, anesthetics and calcium-channel blockers should be titrated carefully to avoid excessive cardiovascular depression. (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Major) Rifampin is a potent inducer of the cytochrome P-450 hepatic enzyme system and can reduce the plasma concentrations and possibly the efficacy of verapamil. Dosages of verapamil may need to be adjusted while the patient is receiving rifampin.
Isoniazid, INH; Rifampin: (Major) Rifampin is a potent inducer of the cytochrome P-450 hepatic enzyme system and can reduce the plasma concentrations and possibly the efficacy of verapamil. Dosages of verapamil may need to be adjusted while the patient is receiving rifampin.
Isoproterenol: (Moderate) The pharmacologic effects of isoproterenol may cause an increase in blood pressure. If isoproterenol is used concomitantly with antihypertensives, the blood pressure should be monitored as the administration of isoproterenol can compromise the effectiveness of antihypertensive agents. (Moderate) The pharmacologic effects of isoproterenol may cause an increase in blood pressure. If isoproterenol is used concomitantly with antihypertensives, the blood pressure should be monitored as the administration of isoproterenol can compromise the effectiveness of antihypertensive agents.
Isosorbide Dinitrate, ISDN: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary. (Moderate) Nitroglycerin can cause hypotension. This action may be additive with other agents that can cause hypotension such as calcium-channel blockers. Patients should be monitored more closely for hypotension if nitroglycerin, including nitroglycerin rectal ointment, is used concurrently with a calcium-channel blocker.
Isosorbide Mononitrate: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary. (Moderate) Nitroglycerin can cause hypotension. This action may be additive with other agents that can cause hypotension such as calcium-channel blockers. Patients should be monitored more closely for hypotension if nitroglycerin, including nitroglycerin rectal ointment, is used concurrently with a calcium-channel blocker.
Isosulfan Blue: (Moderate) Because the use of other nephrotoxic drugs, including ACE inhibitors, is an additive risk factor for nephrotoxicity in patients receiving radiopaque contrast agents, ACE inhibitor therapy should be withheld, when possible, during radiopaque contrast agent administration.
Itraconazole: (Moderate) Calcium-channel blockers can have a negative inotropic effect that may be additive to those of itraconazole. In addition, itraconazole may increase verapamil serum concentrations via inhibition of CYP3A4 with the potential for verapamil toxicity. Edema has been reported in patients receiving concomitantly itraconazole and dihydropyridine calcium-channel blockers; therefore, caution is recommended when administering these medications in combination. A dosage reduction of the calcium-channel blocker may be appropriate.
Ivabradine: (Major) Avoid coadministration of ivabradine and verapamil. Both ivabradine and verapamil may cause bradycardia. In addition, ivabradine is primarily metabolized by CYP3A4; verapamil inhibits CYP3A4. Coadministration may increase the plasma concentrations of ivabradine further increasing the risk for bradycardia exacerbation and conduction disturbances.
Ivacaftor: (Major) If verapamil and ivacaftor are taken together, administer ivacaftor at the usual recommended dose but reduce the frequency to once daily. Coadministration is not recommended in patients younger than 6 months. Ivacaftor is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased ivacaftor exposure by 3-fold.
Ivosidenib: (Major) Avoid coadministration of ivosidenib with verapamil due to increased plasma concentrations of ivosidenib, which increases the risk of QT prolongation. If concomitant use is unavoidable, monitor ECGs for QTc prolongation and monitor electrolytes; correct any electrolyte abnormalities as clinically appropriate. Ivosidenib is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration with another moderate CYP3A4 inhibitor is predicted to increase the ivosidenib single-dose AUC to 173% of control based on physiologically-based pharmacokinetic modeling, with no change in Cmax. Multiple doses of the moderate CYP3A4 inhibitor are predicted to increase the ivosidenib steady-state AUC to 152% of control and AUC to 190% of control.
Ixabepilone: (Moderate) Monitor for ixabepilone toxicity and reduce the ixabepilone dose as needed if concurrent use of verapamil is necessary. Concomitant use may increase ixabepilone exposure and the risk of adverse reactions. Ixabepilone is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor.
Ketamine: (Major) The depression of cardiac contractility, conductivity, and automaticity as well as the vascular dilation associated with general anesthetics may be potentiated by calcium-channel blockers. Alternatively, general anesthetics can potentiate the hypotensive effects of calcium-channel blockers. When used concomitantly, anesthetics and calcium-channel blockers should be titrated carefully to avoid excessive cardiovascular depression. (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Ketoconazole: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with ketoconazole. Coadministration may increase the exposure of verapamil. Verapamil is a CYP3A substrate and ketoconazole is a strong CYP3A4 inhibitor. Clinically significant interactions have been reported with inhibitors of CYP3A4 causing elevation of plasma levels of verapamil. Hypotension, bradyarrhythmias, and other side effects have been observed with some combinations.
Ketoprofen: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Ketorolac: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Labetalol: (Major) Intravenous labetalol is contraindicated with intravenous verapamil use in close proximity (within a few hours). Fatal cardiac arrests have occurred in patients receiving intravenous beta-blockers and intravenous calcium channel blockers. Use oral labetalol and oral verapamil with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Lacosamide: (Moderate) Use lacosamide with caution in patients taking concomitant medications that affect cardiac conduction, such as calcium-channel blockers, because of the risk of AV block, bradycardia, or ventricular tachyarrhythmia. If use together is necessary, obtain an ECG prior to lacosamide initiation and after treatment has been titrated to steady-state. In addition, monitor patients receiving lacosamide via the intravenous route closely.
Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Coadministration of tenofovir disoproxil fumarate with verapamil may result in increased plasma concentrations of tenofovir, leading to an increase in tenofovir-related adverse effects. Tenofovir disoproxil fumarate is a P-gp substrate and verapamil is a P-gp inhibitor.
Lanreotide: (Moderate) Concomitant administration of bradycardia-inducing drugs (e.g., calcium-channel blockers) may have an additive effect on the reduction of heart rate associated with lanreotide. Adjust the calcium-channel blocker dose if necessary.
Lansoprazole; Amoxicillin; Clarithromycin: (Major) Avoid coadministration of clarithromycin and verapamil, particularly in geriatric patients, due to an increased risk of hypotension and acute kidney injury. If the use of a macrolide antibiotic is necessary in a patient receiving verapamil therapy, azithromycin is the preferred agent. If coadministration is unavoidable, monitor blood pressure closely. Verapamil is a CYP3A4 substrate and clarithromycin is a strong CYP3A4 inhibitor. A retrospective, case crossover study, found the risk of hospitalization due to hypotension or shock to be significantly increased in geriatric patients exposed to clarithromycin during concurrent calcium-channel blocker therapy (OR 3.7, 95% CI 2.3-6.1). Concurrent use of azithromycin was not associated with an increased risk of hypotension (OR 1.5, 95% CI 0.8-2.8). One case of a possible verapamil-clarithromycin interaction was reported, which was associated with hypotension.
Lanthanum Carbonate: (Moderate) ACE Inhibitors should not be taken within 2 hours of dosing with lanthanum carbonate. Oral compounds known to interact with cationic antacids may similarly be bound with lanthanum carbonate and have their absorption reduced. If these agents are used concomitantly, separate the dosing intervals appropriately. Monitor the clinical condition of the patient to ensure the proper clinical response to the ACE inhibitor is obtained.
Lapatinib: (Major) Monitor blood pressure, heart rate, and monitor for an increase in lapatinib-related adverse reactions if coadministration of verapamil with lapatinib is necessary. Both drugs are P-glycoprotein (P-gp) substrates and inhibitors. Increased plasma concentrations of lapatinib are likely. Concomitant use may also increase verapamil exposure.
Larotrectinib: (Moderate) Monitor for an increase in larotrectinib-related adverse reactions if concomitant use with verapamil is necessary. Concomitant use may increase larotrectinib exposure. Larotrectinib is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A inhibitor is predicted to increase larotrectinib exposure by 2.7-fold.
Lasmiditan: (Moderate) Monitor heart rate if lasmiditan is coadministered with calcium-channel blockers as concurrent use may increase the risk for bradycardia. Lasmiditan has been associated with lowering of heart rate. In a drug interaction study, addition of a single 200 mg dose of lasmiditan to another heart rate lowering drug decreased heart rate by an additional 5 beats per minute.
Lefamulin: (Moderate) Monitor for increased toxicity of verapamil as well as lefamulin-related adverse effects if oral lefamulin is administered with verapamil as concurrent use may increase exposure from both drugs; an interaction is not expected with intravenous lefamulin. Lefamulin is a CYP3A4 and P-gp substrate and moderate CYP3A4 inhibitor; verapamil is a CYP3A4 substrate and P-gp and moderate CYP3A4 inhibitor.
Lemborexant: (Major) Avoid coadministration of lemborexant and verapamil as concurrent use is expected to significantly increase lemborexant exposure and the risk of adverse effects. Lemborexant is a CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. Coadministration of lemborexant with another moderate CYP3A4 inhibitor increased the lemborexant AUC by up to 4.5-fold.
Lenacapavir: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with lenacapavir. Coadministration may increase the exposure of verapamil. Verapamil is a CYP3A substrate and lenacapavir is a moderate CYP3A inhibitor.
Letermovir: (Moderate) Plasma concentrations of verapamil are expected to be elevated when administered concurrently with letermovir. The magnitude of this interaction may be increased in patients who are also receiving cyclosporine. If these drugs are given together, closely monitor for verapamil-related adverse events. Verapamil is a CYP3A4 substrate. Letermovir is a moderate inhibitor of CYP3A4. However, when given with cyclosporine, the combined effect of letermovir and cyclosporine on CYP3A4 substrates may be similar to a strong CYP3A4 inhibitor. Clinically significant interactions with verapamil have been reported with other moderate and strong inhibitors of CYP3A4.
Leuprolide: (Major) Avoid coadministration of leuprolide with verapamil due to the risk of reduced efficacy of leuprolide. Verapamil can cause hyperprolactinemia, which reduces the number of pituitary gonadotropin releasing hormone (GnRH) receptors; leuprolide is a GnRH analog.
Leuprolide; Norethindrone: (Major) Avoid coadministration of leuprolide with verapamil due to the risk of reduced efficacy of leuprolide. Verapamil can cause hyperprolactinemia, which reduces the number of pituitary gonadotropin releasing hormone (GnRH) receptors; leuprolide is a GnRH analog.
Levamlodipine: (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Levodopa: (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects. (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects.
Levoketoconazole: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with ketoconazole. Coadministration may increase the exposure of verapamil. Verapamil is a CYP3A substrate and ketoconazole is a strong CYP3A4 inhibitor. Clinically significant interactions have been reported with inhibitors of CYP3A4 causing elevation of plasma levels of verapamil. Hypotension, bradyarrhythmias, and other side effects have been observed with some combinations.
Levonorgestrel; Ethinyl Estradiol: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Levonorgestrel; Ethinyl Estradiol; Ferrous Bisglycinate: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Levonorgestrel; Ethinyl Estradiol; Ferrous Fumarate: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Lidocaine: (Moderate) Concomitant use of systemic lidocaine and verapamil may increase lidocaine plasma concentrations by decreasing lidocaine clearance and therefore prolonging the elimination half-life. Monitor for lidocaine toxicity if used together. Lidocaine is a CYP3A4 and CYP1A2 substrate; verapamil inhibits both hepatic isoenzymes.
Lidocaine; Epinephrine: (Moderate) Antihypertensives, including angiotensin-converting enzyme inhibitors, antagonize the vasopressor effects of parenteral epinephrine. (Moderate) Antihypertensives, including calcium-channel blockers, antagonize the vasopressor effects of parenteral epinephrine. (Moderate) Concomitant use of systemic lidocaine and verapamil may increase lidocaine plasma concentrations by decreasing lidocaine clearance and therefore prolonging the elimination half-life. Monitor for lidocaine toxicity if used together. Lidocaine is a CYP3A4 and CYP1A2 substrate; verapamil inhibits both hepatic isoenzymes.
Lidocaine; Prilocaine: (Moderate) Concomitant use of systemic lidocaine and verapamil may increase lidocaine plasma concentrations by decreasing lidocaine clearance and therefore prolonging the elimination half-life. Monitor for lidocaine toxicity if used together. Lidocaine is a CYP3A4 and CYP1A2 substrate; verapamil inhibits both hepatic isoenzymes.
Linagliptin; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Lisdexamfetamine: (Minor) Lisdexamfetamine may increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, like angiotensin-converting enzyme inhibitors (ACE inhibitors). Close monitoring of blood pressure is advised. (Minor) Lisdexamfetamine might increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, like calcium-channel blockers. Close monitoring of blood pressure is advised.
Lithium: (Moderate) Monitor for neurologic adverse reactions during concomitant use of lithium and calcium channel blockers. Concomitant use may increase the risk of neurologic adverse reactions, such as ataxia, tremors, nausea, vomiting, diarrhea, and/or tinnitus. (Moderate) Monitor serum lithium concentrations during concomitant angiotensin-converting enzyme inhibitor use; reduce the lithium dose based on serum lithium concentration and clinical response. Concomitant use may increase steady-state lithium concentrations.
Lofexidine: (Moderate) Because both lofexidine and verapamil can cause hypotension and bradycardia, concurrent use should be avoided if possible. Patients being given lofexidine in an outpatient setting should be capable of and instructed on self-monitoring for hypotension, orthostasis, bradycardia, and associated symptoms. If clinically significant or symptomatic hypotension and/or bradycardia occur, the next dose of lofexidine should be reduced in amount, delayed, or skipped.
Lomitapide: (Contraindicated) Concomitant use of verapamil and lomitapide is contraindicated. If treatment with verapamil is unavoidable, lomitapide should be stopped during the course of treatment. Verapamil is a moderate CYP3A4 inhibitor. The exposure to lomitapide was increased 27-fold in the presence of ketoconazole, a strong CYP3A4 inhibitor. Although concomitant use of moderate CYP3A4 inhibitors with lomitapide has not been studied, a significant increase in lomitapide exposure is likely during concurrent use.
Lonafarnib: (Contraindicated) Coadministration of lonafarnib and verapamil is contraindicated; concurrent use may increase the exposure of both drugs and the risk of adverse effects. Lonafarnib is a sensitive CYP3A4 substrate and strong CYP3A4 inhibitor; verapamil is a CYP3A4 substrate and moderate CYP3A4 inhibitor.
Loop diuretics: (Major) Discontinue the loop diuretic prior to starting trandolapril, if possible, or start trandolapril at the lower dose of 0.5 mg/day. Monitor blood pressure and renal function during concomitant use, particularly when doses are increased. Concomitant use may increase the risk for hypotension or renal failure.
Loperamide: (Moderate) Monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest), if coadministered with verapamil. Concurrent use may increase loperamide exposure. Loperamide is a P-gp substrate and verapamil is a P-gp inhibitor. Coadministration with another P-gp inhibitor increased loperamide plasma concentrations by 2- to 3-fold.
Loperamide; Simethicone: (Moderate) Monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest), if coadministered with verapamil. Concurrent use may increase loperamide exposure. Loperamide is a P-gp substrate and verapamil is a P-gp inhibitor. Coadministration with another P-gp inhibitor increased loperamide plasma concentrations by 2- to 3-fold.
Lopinavir; Ritonavir: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil and ritonavir. Coadministration may increase the exposure of verapamil. Verapamil is a CYP3A4 substrate and ritonavir is a strong CYP3A4 inhibitor.
Loratadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Losartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Losartan; Hydrochlorothiazide, HCTZ: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Lovastatin: (Major) Coadministration of verapamil and lovastatin increases the risk for myopathy/rhabdomyolysis, particularly with higher doses of lovastatin. In patients taking verapamil, the initial lovastatin dose should not exceed 10 mg/day PO. While the FDA-approved product labeling for lovastatin products recommends a maximum lovastatin dosage of 20 mg/day when these agents are used together, the product labeling for verapamil suggests a maximum lovastatin dosage of 40 mg/day. The benefits of the use of lovastatin in patients taking verapamil should be carefully weighed against the risks of this combination. Specific dosage recommendations for pediatric patients receiving this combination are not available.
Lumacaftor; Ivacaftor: (Major) If verapamil and ivacaftor are taken together, administer ivacaftor at the usual recommended dose but reduce the frequency to once daily. Coadministration is not recommended in patients younger than 6 months. Ivacaftor is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased ivacaftor exposure by 3-fold.
Lumacaftor; Ivacaftor: (Moderate) Concomitant use of verapamil and lumacaftor; ivacaftor may decrease the therapeutic effects of verapamil; caution and close monitoring of blood pressure are advised if these drugs are used together. Lumacaftor is a strong CYP3A inducer; in vitro data also suggest that lumacaftor; ivacaftor may induce CYP2C19 and induce and/or inhibit CYP2C8, CYP2C9, and the P-glycoprotein (P-gp) drug transporter. Verapamil is a substrate of CYP3A4, CYP2C8, CYP2C9, and P-gp. Clinically significant interactions have been reported with inducers of CYP3A4; rifampin, a strong CYP3A inducer markedly reduces oral verapamil bioavailability. Of note, verapamil is also a moderate CYP3A inhibitor. Although lumacaftor; ivacaftor is a primary substrate of CYP3A, dosage adjustment of lumacaftor; ivacaftor is not required.
Lumateperone: (Major) Reduce the dose of lumateperone to 21 mg once daily if concomitant use of verapamil is necessary. Concurrent use may increase lumateperone exposure and the risk of adverse effects. Lumateperone is a CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. Coadministration with another moderate CYP3A4 inhibitor increased lumateperone exposure by approximately 2-fold.
Lurasidone: (Major) Verapamil is a moderate inhibitor of CYP3A4 and has the potential for interactions with substrates of CYP3A4 such as lurasidone. Concurrent use of these medications may lead to an increased risk of lurasidone-related adverse reactions. If a moderate inhibitor of CYP3A4 is being prescribed and lurasidone is added in an adult patient, the recommended starting dose of lurasidone is 20 mg/day and the maximum recommended daily dose of lurasidone is 80 mg/day. If a moderate CYP3A4 inhibitor is added to an existing lurasidone regimen, reduce t he lurasidone dose to one-half of the original dose. Patients should be monitored for efficacy and toxicity. In addition, due to the antagonism of lurasidone at alpha-1 adrenergic receptors, the drug may enhance the hypotensive effects of antihypertensive agents. If coadministration is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known. (Moderate) Due to the antagonism of lurasidone at alpha-1 adrenergic receptors, the drug may enhance the hypotensive effects of alpha-blockers and other antihypertensive agents. If concurrent use of lurasidone and antihypertensive agents is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known.
Lurbinectedin: (Major) Avoid coadministration of lurbinectedin and verapamil due to the risk of increased lurbinectedin exposure which may increase the incidence of lurbinectedin-related adverse reactions. If concomitant use is unavoidable, consider reducing the dose of lurbinectedin if clinically indicated. Lurbinectedin is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor.
Magnesium Salts: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).
Magnesium Sulfate; Potassium Sulfate; Sodium Sulfate: (Moderate) Monitor renal function during concomitant angiotensin-converting enzyme inhibitor and magnesium sulfate; potassium sulfate; sodium sulfate bowel preparation due to risk for renal injury; ensure adequate hydration.
Maraviroc: (Moderate) Use caution if coadministration of maraviroc with verapamil is necessary, due to a possible increase in maraviroc exposure. Maraviroc is a CYP3A4/P-glycoprotein (P-gp) substrate and verapamil is a CYP3A4/P-gp inhibitor. Monitor for an increase in adverse effects with concomitant use.
Mavacamten: (Major) Reduce the mavacamten dose by 1 level (i.e., 15 to 10 mg, 10 to 5 mg, or 5 to 2.5 mg) in patients receiving mavacamten and starting verapamil therapy. Avoid initiation of verapamil in patients who are on stable treatment with mavacamten 2.5 mg per day because a lower dose of mavacamten is not available. Initiate mavacamten at the recommended starting dose of 5 mg PO once daily in patients who are on stable verapamil therapy. Expect additive negative inotropic effects during concomitant use of mavacamten and verapamil. If concomitant therapy with verapamil is initiated, or if the dose is increased, monitor left ventricular ejection fraction closely until stable doses and clinical response have been achieved. Avoid concomitant use of mavacamten with verapamil plus a beta-blocker due to association with left ventricular systolic dysfunction and heart failure symptoms. Concomitant use increases mavacamten exposure, which may increase the risk of adverse drug reactions. Mavacamten is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. The impact that a CYP3A inhibitor may have on mavacamten overall exposure varies based on the patient's CYP2C19 metabolizer status. Concomitant use of mavacamten 25 mg with verapamil sustained-release 240 mg increased mavacamten exposure by 15% in CYP2C19 normal and intermediate metabolizers.
Meclofenamate Sodium: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Mefenamic Acid: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Mefloquine: (Moderate) Mefloquine is metabolized by CYP3A4. Verapamil is an inhibitor of this enzyme and may decrease the clearance of mefloquine and increase mefloquine systemic exposure.
Meglitinides: (Moderate) ACE inhibitors may enhance the hypoglycemic effects of insulin or other antidiabetic agents by improving insulin sensitivity. Patients receiving antidiabetic agents can become hypoglycemic if ACE inhibitors are administered concomitantly. Patients receiving these drugs concomitantly with antidiabetic agents should be monitored for changes in glycemic control.
Melatonin: (Moderate) Monitor blood pressure during concomitant calcium-channel blocker and melatonin use. Melatonin may impair the efficacy of calcium-channel blockers. In a placebo-controlled study, melatonin evening ingestion led to significant increases in blood pressure (6.5 mmHg systolic and 4.9 mmHg diastolic) and heart rate (3.9 bpm) throughout the day in patients taking a calcium channel blocker Melatonin appeared to antagonize the antihypertensive effects of the calcium channel blocker.
Meloxicam: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Metformin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Metformin; Repaglinide: (Moderate) ACE inhibitors may enhance the hypoglycemic effects of insulin or other antidiabetic agents by improving insulin sensitivity. Patients receiving antidiabetic agents can become hypoglycemic if ACE inhibitors are administered concomitantly. Patients receiving these drugs concomitantly with antidiabetic agents should be monitored for changes in glycemic control. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Repaglinide is partly metabolized by CYP3A4. Drugs that inhibit CYP3A4 may increase plasma concentrations of repaglinide. Verapamil has been shown to be an inhibitor of CYP3A4. If these drugs are co-administered, dose adjustment of repaglinide may be necessary.
Metformin; Rosiglitazone: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Metformin; Saxagliptin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Minor) Saxagliptin plasma concentrations are expected to increase in the presence of moderate CYP 3A4/5 inhibitors such as verapamil, but saxagliptin dose adjustment is not advised.
Metformin; Sitagliptin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Methadone: (Moderate) Verapamil may increase methadone serum concentrations via inhibition of CYP3A4 metabolism of methadone. Inhibition of methadone metabolism can lead to toxicity including CNS adverse effects and potential for QT prolongation and torsades de pointes when high doses of methadone are used.
Methamphetamine: (Minor) Amphetamines increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, like angiotensin-converting enzyme inhibitors (ACE inhibitors). Close monitoring of blood pressure is advised. (Minor) Amphetamines increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, like calcium-channel blockers. Close monitoring of blood pressure is advised.
Methohexital: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added. (Moderate) Concurrent use of methohexital and antihypertensive agents increases the risk of developing hypotension.
Methoxsalen: (Minor) Preclinical data suggest that calcium-channel blockers could decrease the efficacy of photosensitizing agents used in photodynamic therapy.
Methylphenidate Derivatives: (Moderate) Periodic evaluation of blood pressure is advisable during concurrent use of methylphenidate derivatives and antihypertensive agents, particularly during initial coadministration and after dosage increases of methylphenidate derivatives. Methylphenidate derivatives can reduce the hypotensive effect of antihypertensive agents such as angiotensin-converting enzyme inhibitors. (Moderate) Periodic evaluation of blood pressure is advisable during concurrent use of methylphenidate derivatives and antihypertensive agents, particularly during initial coadministration and after dosage increases of methylphenidate derivatives. Methylphenidate derivatives can reduce the hypotensive effect of antihypertensive agents, including calcium-channel blockers.
Metoprolol: (Major) Intravenous metoprolol is contraindicated with intravenous verapamil use in close proximity (within a few hours). Fatal cardiac arrests have occurred in patients receiving intravenous beta-blockers and intravenous calcium channel blockers. Use oral metoprolol and oral verapamil with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Metoprolol; Hydrochlorothiazide, HCTZ: (Major) Intravenous metoprolol is contraindicated with intravenous verapamil use in close proximity (within a few hours). Fatal cardiac arrests have occurred in patients receiving intravenous beta-blockers and intravenous calcium channel blockers. Use oral metoprolol and oral verapamil with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Midazolam: (Major) A clinically significant interaction has occurred with verapamil, a CYP3A4 inhibitor and oral midazolam, a CYP3A4 substrate. When verapamil and midazolam are coadministered, the AUC and half-life of midazolam are increased and the associated sedation is more pronounced. The significance of an interaction between verapamil and IV midazolam is uncertain, however, but may be less significant due to absence of an effect by verapamil on presystemic midazolam clearance.
Mifepristone: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil and mifepristone. Coadministration may increase the exposure of verapamil. Verapamil is a CYP3A4 substrate and mifepristone is a strong inhibitor of CYP3A4.
Milrinone: (Moderate) Concurrent administration of antihypertensive agents could lead to additive hypotension when administered with milrinone. Titrate milrinone dosage according to hemodynamic response. (Moderate) Concurrent administration of antihypertensive agents could lead to additive hypotension when administered with milrinone. Titrate milrinone dosage according to hemodynamic response.
Mitapivat: (Moderate) Do not exceed mitapivat 20 mg PO twice daily during coadministration with verapamil and monitor hemoglobin and for adverse reactions from mitapivat. Coadministration increases mitapivat concentrations. Mitapivat is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased mitapivat overall exposure by 2.6-fold.
Mitotane: (Moderate) Use caution if mitotane and verapamil are used concomitantly, and monitor for decreased efficacy of verapamil and a possible change in dosage requirements. Mitotane is a strong CYP3A4 inducer and verapamil is a CYP3A4 substrate; coadministration may result in decreased plasma concentrations of verapamil.
Mobocertinib: (Major) Avoid concomitant use of mobocertinib and verapamil; reduce the dose of mobocertinib by approximately 50% and monitor the QT interval more frequently if use is necessary. Concomitant use may increase mobocertinib exposure and the risk for adverse reactions. Mobocertinib is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Use of a moderate CYP3A inhibitor is predicted to increase the overall exposure of mobocertinib and its active metabolites by 100% to 200%.
Nabumetone: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Nadolol: (Moderate) Use verapamil and nadolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Naldemedine: (Major) Monitor for potential naldemedine-related adverse reactions if coadministered with verapamil. The plasma concentrations of naldemedine may be increased during concurrent use. Naldemedine is a substrate of CYP3A4 and P-gp; verapamil is a moderate P-gp inhibitor and a moderate CYP3A4 inhibitor.
Naloxegol: (Major) Avoid concomitant administration of naloxegol and verapamil due to the potential for increased naloxegol exposure. If coadministration cannot be avoided, decrease the naloxegol dosage to 12.5 mg once daily and monitor for adverse reactions including opioid withdrawal symptoms such as hyperhidrosis, chills, diarrhea, abdominal pain, anxiety, irritability, and yawning. Naloxegol is a CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. Coadministration with another moderate CYP3A4 inhibitor increased naloxegol exposure by approximately 3.4-fold.
Nanoparticle Albumin-Bound Paclitaxel: (Moderate) Monitor for an increase in paclitaxel-related adverse reactions if coadministration of nab-paclitaxel with verapamil is necessary due to the risk of increased plasma concentrations of paclitaxel. Nab-paclitaxel is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. In vitro, coadministration with both strong and moderate CYP3A4 inhibitors increased paclitaxel exposure; however, the concentrations used exceeded those found in vivo following normal therapeutic doses. The pharmacokinetics of paclitaxel may also be altered in vivo as a result of interactions with CYP3A4 inhibitors.
Nanoparticle Albumin-Bound Sirolimus: (Major) Avoid concomitant use of sirolimus and verapamil. Coadministration may increase sirolimus concentrations and increase the risk for sirolimus-related adverse effects. Sirolimus is a CYP3A and P-gp substrate and verapamil is a moderate CYP3A and P-gp inhibitor. (Moderate) Sirolimus has been associated with the development of angioedema. The use of sirolimus with other drugs known to cause angioedema, such as angiotensin-converting enzyme inhibitors may increase the risk of developing angioedema. Patients should be monitored for angioedema if any of these drugs are coadministered with sirolimus.
Naproxen: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Naproxen; Esomeprazole: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Naproxen; Pseudoephedrine: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Nateglinide: (Moderate) ACE inhibitors may enhance the hypoglycemic effects of insulin or other antidiabetic agents by improving insulin sensitivity. Patients receiving antidiabetic agents can become hypoglycemic if ACE inhibitors are administered concomitantly. Patients receiving these drugs concomitantly with antidiabetic agents should be monitored for changes in glycemic control.
Nebivolol: (Moderate) Use verapamil and nebivolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Nebivolol; Valsartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy. (Moderate) Use verapamil and nebivolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Nefazodone: (Moderate) Nefazodone is an inhibitor of CYP3A4, and may theoretically increase verapamil serum concentrations. (Minor) Although relatively infrequent, nefazodone may cause orthostatic hypotension in some patients; this effect may be additive with antihypertensive agents. Blood pressure monitoring and dosage adjustments of either drug may be necessary.
Neratinib: (Major) Avoid concomitant use of verapamil with neratinib due to an increased risk of neratinib-related toxicity. Neratinib is a CYP3A4 substrate and verapamil is a dual moderate CYP3A4/P-glycoprotein (P-gp) inhibitor. Simulations using physiologically based pharmacokinetic (PBPK) models suggest that verapamil may increase neratinib exposure by 299%.
Nesiritide, BNP: (Major) The potential for hypotension may be increased when coadministering nesiritide with antihypertensive agents. (Major) The potential for hypotension may be increased when coadministering nesiritide with antihypertensive agents.
Neuromuscular blockers: (Moderate) Concomitant use of neuromuscular blockers and calcium-channel blockers may prolong neuromuscular blockade.
Niacin, Niacinamide: (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents, especially calcium-channel blockers. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise. (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise.
Niacin; Simvastatin: (Major) Do not exceed a simvastatin dose of 10 mg/day in patients taking verapamil due to increased risk of myopathy, including rhabdomyolysis. For patients chronically receiving simvastatin 80 mg/day who need to be started on verapamil, consider switching to an alternative statin with less potential for interaction. Carefully weigh the benefits of combined use of verapamil and simvastatin against the potential risks. Verapamil increases the simvastatin exposure by approximately 2-fold. The interaction is presumed due to increased simvastatin bioavailability via inhibition of CYP3A metabolism and reduction of first-pass metabolism by verapamil. (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents, especially calcium-channel blockers. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise. (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise.
Nifedipine: (Moderate) Diltiazem has been reported to increase the plasma level and hypotensive effects of nifedipine via CYP3A4 inhibition. Verapamil may also inhibit CYP3A4 metabolism of nifedipine.
Nilotinib: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with nilotinib is necessary; also monitor for nilotinib-related side effects. Nilotinib and verapamil are both substrates of and inhibitors of CYP3A4. Elevations of verapamil plasma levels resulting in clinically significant interactions have been reported with other moderate CYP3A4 inhibitors. Increased nilotinib concentrations may increase the risk for treatment-related side effects.
Nintedanib: (Moderate) Dual inhibitors of P-glycoprotein (P-gp) and CYP3A4, such as verapamil, are expected to increase the exposure and clinical effect of nintedanib. If use together is necessary, closely monitor for increased nintedanib side effects including gastrointestinal toxicity (nausea, vomiting, diarrhea, abdominal pain, loss of appetite), headache, elevated liver enzymes, and hypertension. A dose reduction, interruption of therapy, or discontinuation of nintedanib therapy may be necessary. Verapamil is a moderate inhibitor of both P-gp and CYP3A4; nintedanib is a P-gp substrate and a minor CYP3A4 substrate. In drug interactions studies, administration of nintedanib with a dual P-gp and CYP3A4 inhibitor increased nintedanib AUC by 60%.
Nirmatrelvir; Ritonavir: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil and ritonavir. Coadministration may increase the exposure of verapamil. Verapamil is a CYP3A4 substrate and ritonavir is a strong CYP3A4 inhibitor.
Nitrates: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary. (Moderate) Nitroglycerin can cause hypotension. This action may be additive with other agents that can cause hypotension such as calcium-channel blockers. Patients should be monitored more closely for hypotension if nitroglycerin, including nitroglycerin rectal ointment, is used concurrently with a calcium-channel blocker.
Nitroglycerin: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary. (Moderate) Nitroglycerin can cause hypotension. This action may be additive with other agents that can cause hypotension such as calcium-channel blockers. Patients should be monitored more closely for hypotension if nitroglycerin, including nitroglycerin rectal ointment, is used concurrently with a calcium-channel blocker.
Nitroprusside: (Moderate) Additive hypotensive effects may occur when nitroprusside is used concomitantly with other antihypertensive agents. Dosages should be adjusted carefully, according to blood pressure. (Moderate) Additive hypotensive effects may occur when nitroprusside is used concomitantly with other antihypertensive agents. Dosages should be adjusted carefully, according to blood pressure.
Non-Ionic Contrast Media: (Moderate) Because the use of other nephrotoxic drugs, including ACE inhibitors, is an additive risk factor for nephrotoxicity in patients receiving radiopaque contrast agents, ACE inhibitor therapy should be withheld, when possible, during radiopaque contrast agent administration.
Nonsteroidal antiinflammatory drugs: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease. (Moderate) Monitor blood pressure and renal function periodically during concomitant angiotensin-converting enzyme (ACE) inhibitor and nonsteroidal anti-inflammatory drug (NSAID) use. The antihypertensive effect of ACE inhibitors may be diminished by NSAIDs. In persons who are elderly, volume-depleted, or with compromised renal function, coadministration of ACE inhibitors and NSAIDs may result in deterioration of renal function, including possible acute renal failure; these effects are usually reversible.
Norethindrone Acetate; Ethinyl Estradiol; Ferrous fumarate: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Norethindrone; Ethinyl Estradiol: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Norethindrone; Ethinyl Estradiol; Ferrous fumarate: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Norgestimate; Ethinyl Estradiol: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Octreotide: (Moderate) Monitor for bradycardia during concomitant use of verapamil and octreotide and adjust drug dosage based on response as appropriate. Both medications may cause bradycardia and concomitant use may increase bradycardia risk.
Olanzapine: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
Olanzapine; Fluoxetine: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
Olanzapine; Samidorphan: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
Olaparib: (Major) Avoid coadministration of olaparib with verapamil due to the risk of increased olaparib-related adverse reactions. If concomitant use is unavoidable, reduce the dose of olaparib to 150 mg twice daily; the original dose may be resumed 3 to 5 elimination half-lives after verapamil is discontinued. Olaparib is a CYP3A substrate and verapamil is a moderate CYP3A4 inhibitor; concomitant use may increase olaparib exposure. Coadministration with a moderate CYP3A inhibitor is predicted to increase the olaparib Cmax by 14% and the AUC by 121%.
Oliceridine: (Moderate) Monitor patients closely for respiratory depression and sedation at frequent intervals and base subsequent doses on the patient's severity of pain and response to treatment if concomitant administration of oliceridine and verapamil is necessary; less frequent dosing of oliceridine may be required. Concomitant use of oliceridine and verapamil may increase the plasma concentration of oliceridine, resulting in increased or prolonged opioid effects. If verapamil is discontinued, consider increasing the oliceridine dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Oliceridine is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor.
Olmesartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Olmesartan; Amlodipine; Hydrochlorothiazide, HCTZ: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy. (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Olmesartan; Hydrochlorothiazide, HCTZ: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Omaveloxolone: (Major) Avoid concomitant use of omaveloxolone and verapamil. If concomitant use is necessary, decrease omaveloxolone dose to 100 mg once daily; additional dosage reductions may be necessary. Concomitant use may increase omaveloxolone exposure and the risk for omaveloxolone-related adverse effects. Omaveloxolone is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Concomitant use increased omaveloxolone overall exposure by 1.25-fold.
Omeprazole; Amoxicillin; Rifabutin: (Moderate) Rifabutin may induce the CYP3A4 metabolism of calcium-channel blockers such as verapamil and thereby reduce their oral bioavailability. The dosage requirements of verapamil may be increased in patients receiving concurrent enzyme inducers.
Oritavancin: (Moderate) Coadministration of oritavancin and verapamil may result in increases or decreases in verapamil exposure and may increase side effects or decrease efficacy of verapamil. Verapamil is metabolized by CYP3A4 and CYP2C9. Oritavancin weakly induces CYP3A4, while weakly inhibiting CYP2C9. If these drugs are administered concurrently, monitor the patient for signs of toxicity or lack of efficacy.
Osimertinib: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with osimertinib is necessary. Verapamil is a P-glycoprotein (P-gp) substrate and osimertinib is a P-gp inhibitor. Concomitant use may increase verapamil exposure.
Oxaprozin: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Oxcarbazepine: (Moderate) Monitor for decreased plasma levels of MHD, the active metabolite of oxcarbazepine, if coadministered with verapamil. The oxcarbazepine dose may require adjustment after initiation, dosage modification, or discontinuation of verapamil. Verapamil has been shown to decrease MHD exposure by approximately 20%. The mechanism of interaction is unknown.
Oxybutynin: (Moderate) Monitor for oxybutynin-related adverse reactions if coadministration with verapamil is necessary. Oxybutynin is a CYP3A4 substrate and verapamil is a moderate CYP3A inhibitor. Concomitant use with moderate CYP3A4 inhibitors may alter the mean pharmacokinetic parameters of oxybutynin, although the clinical relevance of these potential interactions is unknown.
Oxycodone: (Moderate) Consider a reduced dose of oxycodone with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. If verapamil is discontinued, consider increasing the oxycodone dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Oxycodone is a CYP3A4 substrate, and coadministration with a moderate inhibitor like verapamil can increase oxycodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of oxycodone. If verapamil is discontinued, oxycodone plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to oxycodone.
Oxymetazoline: (Major) The vasoconstricting actions of oxymetazoline, an alpha adrenergic agonist, may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. If these drugs are used together, closely monitor for changes in blood pressure. (Major) The vasoconstricting actions of oxymetazoline, an alpha adrenergic agonist, may reduce the antihypertensive effects produced by calcium-channel blockers. If these drugs are used together, closely monitor for changes in blood pressure.
Ozanimod: (Major) Treatment with ozanimod should generally not be initiated in patients who are concurrently treated with both a heart rate lowering calcium channel blocker (e.g., verapamil) and a beta blocker. If treatment initiation with ozanimod is considered in patients on both a heart rate lowering calcium channel blocker and beta blocker, advice from a cardiologist should be sought.
Paclitaxel: (Minor) Additive bradycardia may occur in patients receiving paclitaxel and other drugs known to cause bradycardia, such as certain calcium-channel blockers. In vitro, the metabolism of paclitaxel via CYP3A4 was inhibited by verapamil, a moderate CYP3A4 inhibitor. However, the verapamil concentrations used exceeded those found in vivo following normal therapeutic doses. Verapamil also blocks the multidrug resistance (MDR) P-glycoprotein, which is a mechanism of resistance to naturally occurring (non-synthetic) chemotherapy agents. Verapamil could enhance paclitaxel's activity and toxicity through this mechanism as well. Small clinical trials have indicated that the coadministration of r-verapamil, an isomer of verapamil, and paclitaxel results in a significant decrease in paclitaxel clearance and an increase in paclitaxel toxicity. Some experts state that pharmacokinetic interactions between paclitaxel and verapamil do not appear to be clinically significant in vivo. However, combining the drugs in clinical practice may require close monitoring; monitor for paclitaxel induced side effects such as myelosuppression, infection, or peripheral neuropathy.
Pacritinib: (Major) Avoid concurrent use of pacritinib with verapamil due to the risk of increased pacritinib exposure which increases the risk of adverse reactions. Pacritinib is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor.
Paliperidone: (Moderate) Paliperidone may cause orthostatic hypotension, thereby enhancing the hypotensive effects of antihypertensive agents. Orthostatic vital signs should be monitored in patients receiving paliperidone and angiotensin-converting enzyme inhibitors who are susceptible to hypotension. (Moderate) Paliperidone may cause orthostatic hypotension, thereby enhancing the hypotensive effects of antihypertensive agents. Orthostatic vital signs should be monitored in patients receiving paliperidone and calcium-channel blockers who are susceptible to hypotension.
Palovarotene: (Major) Avoid concomitant use of palovarotene and verapamil due to the risk for increased palovarotene exposure which may increase the risk for adverse effects. If concomitant use is necessary, decrease the palovarotene dose by half. Palovarotene is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Concomitant use with another moderate CYP3A inhibitor increased palovarotene overall exposure by 2.5-fold.
Paricalcitol: (Moderate) Paricalcitol is partially metabolized by CYP3A4. Care should be taken when dosing paricalcitol with strong CYP3A4 inhibitors, such as verapamil. Dose adjustments of paricalcitol may be required. Monitor plasma PTH and serum calcium and phosphorous concentrations if a patient initiates or discontinues therapy with this combination.
Pasireotide: (Major) Pasireotide may cause a decrease in heart rate. Closely monitor patients who are also taking drugs associated with bradycardia such as calcium-channel blockers. Dose adjustments of calcium-channel blockers may be necessary.
Pazopanib: (Moderate) Pazopanib is a weak inhibitor of and substrate for CYP3A4 and P-glycoprotein (P-gp). Verapamil is a substrate for and an inhibitor of CYP3A4 and P-gp. Concurrent administration may result in increased pazopanib concentrations and/or increased verapamil concentrations. Dose reduction of pazopanib should be considered when coadministration of pazopanib and verapamil is necessary.
Pemigatinib: (Major) Avoid coadministration of pemigatinib and verapamil due to the risk of increased pemigatinib exposure which may increase the risk of adverse reactions. If coadministration is unavoidable, reduce the dose of pemigatinib to 9 mg PO once daily if original dose was 13.5 mg per day and to 4.5 mg PO once daily if original dose was 9 mg per day. If verapamil is discontinued, resume the original pemigatinib dose after 3 elimination half-lives of verapamil. Pemigatinib is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration with a moderate CYP3A4 inhibitor is predicted to increase pemigatinib exposure by approximately 50% to 80%.
Pentobarbital: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added.
Pentoxifylline: (Moderate) Pentoxifylline has been used concurrently with antihypertensive drugs (beta blockers, diuretics) without observed problems. Small decreases in blood pressure have been observed in some patients treated with pentoxifylline; periodic systemic blood pressure monitoring is recommended for patients receiving concomitant antihypertensives. If indicated, dosage of the antihypertensive agents should be reduced.
Perindopril; Amlodipine: (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Pexidartinib: (Major) Avoid concomitant use of pexidartinib and verapamil due to the risk of increased pexidartinib exposure which may increase the risk for adverse effects. If concomitant use is necessary, reduce the pexidartinib dosage as follows: 500 mg/day or 375 mg/day of pexidartinib, reduce to 125 mg twice daily; 250 mg/day of pexidartinib, reduce to 125 mg once daily. If verapamil is discontinued, increase the pexidartinib dose to the original dose after 3 plasma half-lives of verapamil. Pexidartinib is a CYP3A substrate; verapamil is a moderate CYP3A inhibitor. Coadministration of another moderate CYP3A inhibitor increased pexidartinib overall exposure by 67%.
Phenelzine: (Moderate) Additive hypotensive effects may be seen when monoamine oxidase inhibitors (MAOIs) are combined with antihypertensives. Careful monitoring of blood pressure is suggested during concurrent therapy of MAOIs with angiotensin-converting enzyme inhibitors (ACE inhibitors). Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider. (Moderate) Additive hypotensive effects may be seen when monoamine oxidase inhibitors (MAOIs) are combined with antihypertensives. Careful monitoring of blood pressure is suggested during concurrent therapy of MAOIs with calcium-channel blockers. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider.
Phenobarbital: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added.
Phenoxybenzamine: (Moderate) Additive pharmacodynamic effects are especially prominent when verapamil is co-administered with alpha-blockers or beta-blockers. The use of alpha-blockers with verapamil can lead to excessive hypotension.
Phentolamine: (Moderate) Additive pharmacodynamic effects are especially prominent when verapamil is co-administered with alpha-blockers. The use of alpha-blockers with verapamil can lead to excessive hypotension.
Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Photosensitizing agents (topical): (Minor) Preclinical data suggest that calcium-channel blockers could decrease the efficacy of photosensitizing agents used in photodynamic therapy.
Pimozide: (Major) Concurrent use of pimozide and verapamil should be avoided. Pimozide is metabolized primarily through CYP3A4, and verapamil is a CYP3A4 inhibitor. Elevated pimozide concentrations occurring through inhibition of CYP3A4 can lead to QT prolongation, ventricular arrhythmias, and sudden death.
Pindolol: (Moderate) Use verapamil and pindolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Pioglitazone; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Piroxicam: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Polyethylene Glycol; Electrolytes: (Moderate) Monitor renal function during concomitant angiotensin-converting enzyme inhibitor and magnesium sulfate; potassium sulfate; sodium sulfate bowel preparation due to risk for renal injury; ensure adequate hydration.
Polyethylene Glycol; Electrolytes; Ascorbic Acid: (Moderate) Monitor renal function during concomitant angiotensin-converting enzyme inhibitor and magnesium sulfate; potassium sulfate; sodium sulfate bowel preparation due to risk for renal injury; ensure adequate hydration.
Ponesimod: (Major) Avoid concomitant use of ponesimod and medications that may decrease heart rate such as verapamil due to the risk for severe bradycardia and heart block. Consider consultation from a cardiologist if concomitant use is necessary.
Posaconazole: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with posaconazole is necessary. Concurrent use may result in elevated verapamil concentrations. Verapamil is a CYP3A4 substrate and posaconazole is a strong CYP3A4 inhibitor.
Potassium Phosphate: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
Potassium Phosphate; Sodium Phosphate: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
Potassium: (Moderate) Monitor serum potassium concentrations closely if potassium supplements and angiotensin-converting enzyme inhibitors (ACE inhibitors) are used together. Concomitant use may increase the risk of hyperkalemia.
Pralsetinib: (Major) Avoid concomitant use of verapamil with pralsetinib due to the risk of increased pralsetinib exposure which may increase the risk of adverse reactions. If concomitant use is necessary, reduce the daily dose of pralsetinib by 100 mg. Pralsetinib is a CYP3A and P-gp substrate and verapamil is a combined moderate CYP3A and P-gp inhibitor. Coadministration increased the overall exposure of pralsetinib by 108%.
Pramlintide: (Moderate) ACE inhibitors may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. Patients receiving these drugs concomitantly with antidiabetic agents should be monitored for changes in glycemic control.
Prazosin: (Moderate) Prazosin is well-known to produce a 'first-dose' phenomenon. Some patients develop significant hypotension shortly after administration of the first dose. The first dose response (acute postural hypotension) of prazosin may be exaggerated in patients who are receiving beta-adrenergic blockers, diuretics, or other antihypertensive agents. Concomitant administration of prazosin with other antihypertensive agents is not prohibited, however. This can be therapeutically advantageous, but lower dosages of each agent should be used. (Moderate) Prazosin is well-known to produce a 'first-dose' phenomenon. Some patients develop significant hypotension shortly after administration of the first dose. The first dose response (acute postural hypotension) of prazosin may be exaggerated in patients who are receiving beta-adrenergic blockers, diuretics, or other antihypertensive agents. Concomitant administration of prazosin with other antihypertensive agents is not prohibited, however. This can be therapeutically advantageous, but lower dosages of each agent should be used. The use of alpha-blockers with verapamil can lead to excessive hypotension; In addition, verapamil has been reported to increase the AUC and Cmax of prazosin.
Prednisone: (Minor) The absorption of verapamil can also be reduced by the cyclophosphamide, vincristine, procarbazine, prednisone (COPP) chemotherapeutic drug regimen.
Pregabalin: (Moderate) Monitor for signs and symptoms of angioedema during concomitant angiotensin-converting enzyme inhibitor and pregabalin use. Concomitant use may increase the risk of developing angioedema.
Prilocaine; Epinephrine: (Moderate) Antihypertensives, including angiotensin-converting enzyme inhibitors, antagonize the vasopressor effects of parenteral epinephrine. (Moderate) Antihypertensives, including calcium-channel blockers, antagonize the vasopressor effects of parenteral epinephrine.
Primidone: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added.
Probenecid; Colchicine: (Major) Due to the risk for serious colchicine toxicity including multi-organ failure and death, avoid coadministration of colchicine and verapamil in patients with normal renal and hepatic function unless the use of both agents is imperative. Coadministration is contraindicated in patients with renal or hepatic impairment because colchicine accumulation may be greater in these populations. Verapamil can inhibit colchicine's metabolism via P-glycoprotein (P-gp) and CYP3A4, resulting in increased colchicine exposure. If coadministration in patients with normal renal and hepatic function cannot be avoided, adjust the dose of colchicine by either reducing the daily dose or the dosage frequency, and carefully monitor for colchicine toxicity. Specific dosage adjustment recommendations are available for the Colcrys product for patients who have taken a P-gp and moderate CYP3A4 inhibitor like verapamil in the past 14 days or require concurrent use: for prophylaxis of gout flares, if the original dose is 0.6 mg twice daily, decrease to 0.3 mg once daily or if the original dose is 0.6 mg once daily, decrease to 0.3 mg once every other day; for treatment of gout flares, give 0.6 mg as a single dose, then 0.3 mg 1 hour later, and do not repeat for at least 3 days; for familial Mediterranean fever, do not exceed a 0.6 mg/day.
Procainamide: (Moderate) Procainamide can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents. Intravenous administration of procainamide is more likely to cause hypotensive effects. (Moderate) Procainamide can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents. Intravenous administration of procainamide is more likely to cause hypotensive effects.
Procarbazine: (Minor) The absorption of verapam il can also be reduced by the cyclophosphamide, vincristine, procarbazine, prednisone (COPP) chemotherapeutic drug regimen.
Progesterone: (Minor) The metabolism of progesterone may be inhibited by verapamil, an inhibitor of cytochrome P450 3A4 hepatic enzymes.
Promethazine; Phenylephrine: (Moderate) Phenylephrine's cardiovascular effects may reduce the antihypertensive effects of calcium-channel blockers. Well-controlled hypertensive patients receiving decongestant sympathomimetics at recommended doses do not appear to be at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients. (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure, however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
Propafenone: (Moderate) Coadministration of propafenone with verapamil has the potential to cause additive decreases in AV conduction and/or negative inotropic effects. In addition, concurrent use may increase propafenone exposure and therefore increase the risk of proarrhythmias. Avoid simultaneous use of propafenone and verapamil with a CYP2D6 inhibitor or in patients with CYP2D6 deficiency. Propafenone is a CYP3A4 and CYP2D6 substrate and verapamil is a moderate CYP3A4 inhibitor.
Propofol: (Major) The depression of cardiac contractility, conductivity, and automaticity as well as the vascular dilation associated with general anesthetics may be potentiated by calcium-channel blockers. Alternatively, general anesthetics can potentiate the hypotensive effects of calcium-channel blockers. When used concomitantly, anesthetics and calcium-channel blockers should be titrated carefully to avoid excessive cardiovascular depression. (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Propranolol: (Major) Intravenous propranolol is contraindicated with intravenous verapamil use in close proximity (within a few hours). Fatal cardiac arrests have occurred in patients receiving intravenous beta-blockers and intravenous calcium channel blockers. Use oral propranolol and oral verapamil with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension. A decrease in propranolol clearance has been observed when administered concomitantly with verapamil.
Propranolol; Hydrochlorothiazide, HCTZ: (Major) Intravenous propranolol is contraindicated with intravenous verapamil use in close proximity (within a few hours). Fatal cardiac arrests have occurred in patients receiving intravenous beta-blockers and intravenous calcium channel blockers. Use oral propranolol and oral verapamil with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension. A decrease in propranolol clearance has been observed when administered concomitantly with verapamil.
Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Pseudoephedrine; Triprolidine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin-converting enzyme inhibitors. Monitor heart rate and blood pressure. (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by calcium-channel blockers. Monitor blood pressure and heart rate.
Quazepam: (Moderate) CYP3A4 inhibitors, including verapamil, may reduce the metabolism of quazepam and increase the potential for benzodiazepine toxicity.
Quetiapine: (Minor) Verapamil may inhibit the CYP3A4-mediated metabolism of quetiapine, leading to increased serum concentrations of quetiapine. The manufacturer of quetiapine recommends a reduced dosage during concurrent administration of CYP3A4 inhibitors.
Quinidine: (Major) Pharmacokinetic and pharmacodynamic interactions exist between quinidine and verapamil. Oral verapamil has been shown to reduce the clearance and metabolism of oral quinidine. Quinidine half-life increased and plasma concentrations were higher after verapamil. No changes in quinidine protein binding were observed. In addition to the pharmacokinetic interaction which may potentiate quinidine's clinical effects, both quinidine and verapamil can cause hypotension. When quinidine and verapamil are coadministered in doses that are each well tolerated as monotherapy, hypotension attributable to additive peripheral (alpha)-blockade is sometimes reported. Concurrent use of verapamil and quinidine in patients with hypertrophic cardiomyopathy or arrhythmias can cause significant hypotension. It is recommended to avoid combined therapy with verapamil and quinidine in patients with hypertrophic cardiomyopathy. Quinidine and verapamil may also have additive negative inotropic effects. Concurrent use of verapamil and quinidine should be monitored carefully for electrophysiologic and hemodynamic effects. (Moderate) Quinidine can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents due to the potential for additive hypotension.
Quinine: (Moderate) Quinine is a substrate of P-glycoprotein (PGP) and CYP3A4 and verapamil is a PGP and CYP3A4 inhibitor; therefore, quinine concentrations could be increased with coadministration. Additionally, verapamil is a CYP3A4 substrate and quinine can inhibit CYP3A4; therefore, verapamil concentrations could also be increased with coadministration. Monitor patients for increased side effects of quinine and verapamil if these drugs are given together.
Ramelteon: (Moderate) Coadministration of ramelteon with inhibitors of CYP3A4, such as verapamil, may lead to increases in the serum concentrations of ramelteon.
Ranolazine: (Major) The dose of ranolazine, a CYP3A4 and P-glycoprotein substrate, should be limited to 500 mg PO twice daily when coadministered with verapamil, a moderate CYP3A inhibitor. Verapamil (120 mg three times daily) causes dose-dependent increases in the average steady-state concentrations of ranolazine by about 2-fold.
Rasagiline: (Moderate) Additive hypotensive effects may be seen when monoamine oxidase inhibitors (MAOIs) are combined with antihypertensives. Careful monitoring of blood pressure is suggested during concurrent therapy of MAOIs with angiotensin-converting enzyme inhibitors (ACE inhibitors). Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider. (Moderate) Additive hypotensive effects may be seen when monoamine oxidase inhibitors (MAOIs) are combined with antihypertensives. Careful monitoring of blood pressure is suggested during concurrent therapy of MAOIs with calcium-channel blockers. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider during concurrent use of an MAOI and a calcium-channel blocker.
Red Yeast Rice: (Major) Red yeast rice is best avoided by patients taking CYP3A4 inhibitors, such as verapamil. Since certain red yeast rice products contain lovastatin, clinicians should use red yeast rice cautiously in combination with drugs known to interact with lovastatin. CYP3A4 inhibitors have been shown to increase HMG-CoA reductase activity and potential for myopathy/rhabdomyolysis when coadministered with lovastatin, particularly with higher doses of lovastatin. The benefits of the use of lovastatin in patients taking verapamil should be carefully weighed against the risks of this combination.
Regadenoson: (Major) Because of the potential for additive or synergistic depressant effects on SA and AV nodes, regadenoson should be used with caution in the presence of agents that slow cardiac conduction, such as verapamil.
Relugolix: (Major) Avoid concomitant use of relugolix and oral verapamil. Concomitant use may increase relugolix exposure and the risk of relugolix-related adverse effects. If concomitant use is unavoidable, administer verapamil at least 6 hours after relugolix and monitor for adverse reactions. Relugolix is a P-glycoprotein (P-gp) substrate and verapamil is a P-gp inhibitor.
Relugolix; Estradiol; Norethindrone acetate: (Major) Avoid concomitant use of relugolix and oral verapamil. Concomitant use may increase relugolix exposure and the risk of relugolix-related adverse effects. If concomitant use is unavoidable, administer verapamil at least 6 hours after relugolix and monitor for adverse reactions. Relugolix is a P-glycoprotein (P-gp) substrate and verapamil is a P-gp inhibitor. (Minor) Verapamil inhibits CYP3A4 activity. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when verapamil is coadministered with either estrogens or combined hormonal contraceptives.
Remifentanil: (Moderate) The risk of significant hypotension and/or bradycardia during therapy with remifentanil may be increased in patients receiving calcium-channel blockers due to additive hypotensive effects.
Repaglinide: (Moderate) ACE inhibitors may enhance the hypoglycemic effects of insulin or other antidiabetic agents by improving insulin sensitivity. Patients receiving antidiabetic agents can become hypoglycemic if ACE inhibitors are administered concomitantly. Patients receiving these drugs concomitantly with antidiabetic agents should be monitored for changes in glycemic control. (Moderate) Repaglinide is partly metabolized by CYP3A4. Drugs that inhibit CYP3A4 may increase plasma concentrations of repaglinide. Verapamil has been shown to be an inhibitor of CYP3A4. If these drugs are co-administered, dose adjustment of repaglinide may be necessary.
Ribociclib: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with ribociclib is necessary. Verapamil is a CYP3A4 substrate and ribociclib is a strong CYP3A4 inhibitor.
Ribociclib; Letrozole: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with ribociclib is necessary. Verapamil is a CYP3A4 substrate and ribociclib is a strong CYP3A4 inhibitor.
Rifabutin: (Moderate) Rifabutin may induce the CYP3A4 metabolism of calcium-channel blockers such as verapamil and thereby reduce their oral bioavailability. The dosage requirements of verapamil may be increased in patients receiving concurrent enzyme inducers.
Rifampin: (Major) Rifampin is a potent inducer of the cytochrome P-450 hepatic enzyme system and can reduce the plasma concentrations and possibly the efficacy of verapamil. Dosages of verapamil may need to be adjusted while the patient is receiving rifampin.
Rifapentine: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with rifapentine is necessary. Concomitant use may decrease plasma concentrations of verapamil. Verapamil is a CYP3A4 substrate and rifapentine is a strong CYP3A4 inducer.
Rifaximin: (Moderate) Monitor for an increase in rifaximin-related adverse reactions if coadministration with verapamil is necessary. Concomitant use may increase rifaximin exposure. In patients with hepatic impairment, a potential additive effect of reduced metabolism may further increase systemic rifaximin exposure. Rifaximin is a P-gp substrate and verapamil is a P-gp inhibitor. Coadministration with another P-gp inhibitor increased rifaximin overall exposure by 124-fold.
Rilpivirine: (Moderate) Close clinical monitoring is advised when administering verapamil with rilpivirine due to an increased potential for rilpivirine-related adverse events. Although this interaction has not been studied, predictions can be made based on metabolic pathways. Verapamil is an inhibitor of the hepatic isoenzyme CYP3A4; rilpivirine is metabolized by this isoenzyme. Coadministration may result in increased rilpivirine plasma concentrations.
Rimegepant: (Major) Avoid a second dose of rimegepant within 48 hours if coadministered with verapamil; concurrent use may increase rimegepant exposure. Rimegepant is a CYP3A4 and P-gp substrate; verapamil is a moderate CYP3A4 inhibitor and a P-gp inhibitor.
Risperidone: (Moderate) Risperidone has been associated with orthostatic hypotension and may enhance the hypotensive effects of antihypertensive agents. Clinically significant hypotension has been observed with concomitant use of risperidone and antihypertensive medications. Lower initial doses or slower dose titration of risperidone may be necessary in patients receiving antihypertensive agents concomitantly. (Moderate) Risperidone may induce orthostatic hypotension and thus enhance the hypotensive effects of antihypertensive agents. Lower initial doses or slower dose titration of risperidone may be necessary in patients receiving antihypertensive agents concomitantly.
Ritlecitinib: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with ritlecitinib. Coadministration may increase the exposure of verapamil. Verapamil is a CYP3A substrate and ritlecitinib is a moderate CYP3A inhibitor.
Ritonavir: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil and ritonavir. Coadministration may increase the exposure of verapamil. Verapamil is a CYP3A4 substrate and ritonavir is a strong CYP3A4 inhibitor.
Rivaroxaban: (Moderate) Avoid coadministration of rivaroxaban and verapamil in patients with renal impairment (CrCL 15 to 79 mL/minute) unless the potential benefit justifies the potential risk. Rivaroxaban is a CYP3A4 and P-glycoprotein (P-gp) inhibitor and verapamil is a P-gp and moderate CYP3A4 inhibitor. In a pharmacokinetic trial, coadministration with another combined moderate CYP3A4/P-gp inhibitor increased the AUC of rivaroxaban by 76% in patients with mild renal impairment (CrCL 50 to 79 mL/minute) and by 99% in patients with moderate renal impairment (CrCL 30 to 49 mL/minute) compared to patients with normal renal function (CrCL greater than 80 mL/minute); similar trends in pharmacodynamic effects were also observed.
Romidepsin: (Moderate) Romidepsin is a substrate for CYP3A4 and P-glycoprotein (P-gp). Verapamil is an inhibitor of CYP3A4 and P-gp. Concurrent administration of romidepsin with an inhibitor of CYP3A4 and P-gp may cause an increase in systemic romidepsin concentrations. Use caution when concomitant administration of these agents is necessary.
Ruxolitinib: (Minor) Ruxolitinib is a CYP3A4 substrate. When used with drugs that are mild or moderate inhibitors of CYP3A4 such as verapamil, a dose adjustment is not necessary, but monitoring patients for toxicity may be prudent. There was an 8% and 27% increase in the Cmax and AUC of a single dose of ruxolitinib 10 mg, respectively, when the dose was given after a short course of erythromycin 500 mg PO twice daily for 4 days. The change in the pharmacodynamic marker pSTAT3 inhibition was consistent with the increase in exposure.
Sacubitril; Valsartan: (Contraindicated) Sacubitril; valsartan is contraindicated with the concomitant use of angiotensin-converting enzyme inhibitors (ACE inhibitors) due to the increased risk of angioedema. Do not administer sacubitril; valsartan within 36 hours of switching to or from an ACE inhibitor. (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Salicylates: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Saxagliptin: (Minor) Saxagliptin plasma concentrations are expected to increase in the presence of moderate CYP 3A4/5 inhibitors such as verapamil, but saxagliptin dose adjustment is not advised.
Secobarbital: (Major) Barbiturates have been shown to enhance the hepatic clearance of verapamil. The effect on oral verapamil is greater than for IV verapamil, but a significant increase in clearance has been noted for both verapamil dosage forms during concomitant administration of a barbiturate. Patients receiving verapamil should be monitored for loss of therapeutic effect if barbiturates are added.
Segesterone Acetate; Ethinyl Estradiol: (Minor) Coadministration of segesterone, a CYP3A4 substrate and verapamil, a moderate CYP3A4 inhibitor may increase the serum concentration of segesterone. (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients.
Selpercatinib: (Major) Avoid coadministration of selpercatinib and verapamil due to the risk of increased selpercatinib exposure which may increase the risk of adverse reactions, including QT prolongation. If coadministration is unavoidable, reduce the dose of selpercatinib to 80 mg PO twice daily if original dose was 120 mg twice daily, and to 120 mg PO twice daily if original dose was 160 mg twice daily. Monitor ECGs for QT prolongation more frequently. If verapamil is discontinued, resume the original selpercatinib dose after 3 to 5 elimination half-lives of verapamil. Selpercatinib is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration with verapamil is predicted to increase selpercatinib exposure by 60% to 99%.
Selumetinib: (Major) Avoid coadministration of selumetinib and verapamil due to the risk of increased selumetinib exposure which may increase the risk of adverse reactions. If coadministration is unavoidable, reduce the dose of selumetinib to 20 mg/m2 PO twice daily if original dose was 25 mg/m2 twice daily and 15 mg/m2 PO twice daily if original dose was 20 mg/m2 twice daily. If verapamil is discontinued, resume the original selumetinib dose after 3 elimination half-lives of verapamil. Selumetinib is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration with a moderate CYP3A4 inhibitor is predicted to increase selumetinib exposure by 41%.
Sevoflurane: (Major) The depression of cardiac contractility, conductivity, and automaticity as well as the vascular dilation associated with general anesthetics may be potentiated by calcium-channel blockers. Alternatively, general anesthetics can potentiate the hypotensive effects of calcium-channel blockers. When used concomitantly, anesthetics and calcium-channel blockers should be titrated carefully to avoid excessive cardiovascular depression. (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
SGLT2 Inhibitors: (Moderate) Monitor blood glucose during concomitant SGLT2 inhibitor and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Sildenafil: (Moderate) Monitor for an increase in sildenafil-related adverse reactions if coadministration with verapamil is necessary; consider a starting dose of 25 mg of sildenafil when prescribed for erectile dysfunction. Sildenafil is a sensitive CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. In a drug interaction study, coadministration with a moderate CYP3A4 inhibitor increased the Cmax and AUC of sildenafil by 160% and 182%, respectively. Predictions based on a pharmacokinetic model suggest that drug-drug interactions with CYP3A4 inhibitors will be less for sildenafil injection than those observed after oral sildenafil administration.
Silodosin: (Moderate) During clinical trials with silodosin, the incidence of dizziness and orthostatic hypotension was higher in patients receiving concomitant antihypertensive treatment. Thus, caution is advisable when silodosin is administered with antihypertensive agents. (Moderate) Monitor for silodosin-related adverse effects if coadministered with verapamil; silodosin exposure may be increased. In addition the incidence of dizziness and orthostatic hypotension were increased in patients also receiving antihypertensive medications in clinical trials. Verapamil is a moderate CYP3A4 inhibitor and P-gp inhibitor; silodosin is a CYP3A4 and P-gp substrate. Although the effect of moderate CYP3A4 inhibitors on silodosin exposure has not been studied, coadministration of a combined P-gp/strong CYP3A4 inhibitor increased the silodosin AUC by 2.9-fold to 3.2-fold.
Simvastatin: (Major) Do not exceed a simvastatin dose of 10 mg/day in patients taking verapamil due to increased risk of myopathy, including rhabdomyolysis. For patients chronically receiving simvastatin 80 mg/day who need to be started on verapamil, consider switching to an alternative statin with less potential for interaction. Carefully weigh the benefits of combined use of verapamil and simvastatin against the potential risks. Verapamil increases the simvastatin exposure by approximately 2-fold. The interaction is presumed due to increased simvastatin bioavailability via inhibition of CYP3A metabolism and reduction of first-pass metabolism by verapamil.
Sincalide: (Moderate) Sincalide-induced gallbladder ejection fraction may be affected by calcium-channel blockers. False study results are possible in patients with drug-induced hyper- or hypo-responsiveness; thorough patient history is important in the interpretation of results.
Siponimod: (Major) In general, do not initiate treatment with siponimod in patients receiving verapamil due to the potential for additive effects on heart rate. Consult a cardiologist regarding appropriate monitoring if siponimod use is required. Additionally, concomitant use of siponimod and verapamil may increase siponimod exposure. If the patient is also receiving a drug regimen containing a moderate CYP2C9 inhibitor, use of siponimod is not recommended due to a significant increase in siponimod exposure. Siponimod is a CYP2C9 and CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. Coadministration with a moderate CYP2C9/CYP3A4 dual inhibitor led to a 2-fold increase in the exposure of siponimod.
Sirolimus: (Moderate) Monitor sirolimus concentrations and adjust sirolimus dosage as appropriate during concomitant use of verapamil. Coadministration may increase sirolimus concentrations and the risk for sirolimus-related adverse effects. Sirolimus is a CYP3A and P-gp substrate and verapamil is a moderate CYP3A and P-gp inhibitor. Concomitant use increased sirolimus overall exposure by 2.2-fold in a drug interaction study. (Moderate) Sirolimus has been associated with the development of angioedema. The use of sirolimus with other drugs known to cause angioedema, such as angiotensin-converting enzyme inhibitors may increase the risk of developing angioedema. Patients should be monitored for angioedema if any of these drugs are coadministered with sirolimus.
Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as angiotensin-converting enzyme inhibitors, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Moderate) Use caution when prescribing sodium picosulfate; magnesium oxide; anhydrous citric acid in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors). In addition, use caution in patients receiving drugs where hypokalemia is a particular risk.
Sodium Sulfate; Magnesium Sulfate; Potassium Chloride: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).
Sofosbuvir; Velpatasvir: (Moderate) Use caution when administering velpatasvir with verapamil. Taking these medications together may increase the plasma concentrations of both drugs, potentially resulting in adverse events. Both drugs are substrates and inhibitors of the drug transporter P-glycoprotein (P-gp). In addition, verapamil is an inhibitor of the hepatic enzyme CYP3A4. Velpatasvir is a CYP3A4 substrate.
Sofosbuvir; Velpatasvir; Voxilaprevir: (Moderate) Plasma concentrations of verapamil, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with voxilaprevir, a P-gp inhibitor. Monitor patients for changes in blood pressure and increased side effects if these drugs are administered concurrently. (Moderate) Use caution when administering velpatasvir with verapamil. Taking these medications together may increase the plasma concentrations of both drugs, potentially resulting in adverse events. Both drugs are substrates and inhibitors of the drug transporter P-glycoprotein (P-gp). In addition, verapamil is an inhibitor of the hepatic enzyme CYP3A4. Velpatasvir is a CYP3A4 substrate.
Sonidegib: (Major) Avoid the concomitant use of sonidegib and verapamil as sonidegib levels may be significantly increased resulting in increased risk of adverse events, particularly musculoskeletal toxicity. Sonidegib is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Physiologic-based pharmacokinetic (PBPK) simulations indicate a moderate 3A4 inhibitor would increase the sonidegib AUC by 1.8-fold if administered for 14 days and by 2.8-fold if the moderate CYP3A inhibitor is administered with sonidegib for more than 14 days.
Sorafenib: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with sorafenib is necessary. Verapamil is a P-glycoprotein (P-gp) substrate. Sorafenib inhibits P-gp in vitro and may increase the concentrations of concomitantly administered drugs that are P-gp substrates.
Sotalol: (Moderate) Monitor blood pressure and heart rate if concomitant use of verapamil and sotalol is necessary. Concomitant use can increase the risk of bradycardia or hypotension.
Sparsentan: (Major) Hold angiotensin-converting enzyme inhibitor therapy when initiating sparsentan and until a stable dose of sparsentan is achieved. Frequently monitor potassium during concomitant use due to the increased risk for hyperkalemia. (Moderate) Monitor for an increase in sparsentan-related adverse effects if concomitant use with verapamil is necessary. Concomitant use may increase sparsentan exposure. Sparsentan is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Concomitant use with another moderate CYP3A inhibitor increased sparsentan overall exposure by 70%.
Spironolactone: (Moderate) Monitor serum potassium concentrations closely if ACE inhibitors and spironolactone are used together. Concomitant use may increase the risk of hyperkalemia, especially in elderly patients or patients with impaired renal function.
Spironolactone; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum potassium concentrations closely if ACE inhibitors and spironolactone are used together. Concomitant use may increase the risk of hyperkalemia, especially in elderly patients or patients with impaired renal function.
St. John's Wort, Hypericum perforatum: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with St. John's Wort is necessary. Concomitant use may decrease plasma concentrations of verapamil. Verapamil is a CYP3A4 substrate and St. John's Wort is a strong CYP3A4 inducer.
Sufentanil: (Moderate) Because the dose of the sufentanil sublingual tablets cannot be titrated, consider an alternate opiate if verapamil must be administered. Consider a reduced dose of sufentanil injection with frequent monitoring for respiratory depression and sedation if concurrent use of verapamil is necessary. If verapamil is discontinued, consider increasing the sufentanil injection dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Sufentanil is a CYP3A4 substrate, and coadministration with a moderate CYP3A4 inhibitor like verapamil can increase sufentanil exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of sufentanil. If verapamil is discontinued, sufentanil plasma concentrations will decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to sufentanil.
Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Moderate) Monitor for hyperkalemia if concomitant use of an angiotensin-converting enzyme (ACE) inhibitor and trimethoprim is necessary. Avoid concomitant use and consider alternative antibiotic therapy in patients with additional risk factors for hyperkalemia, including patients older than 65 years, those with underlying disorders of potassium metabolism, renal insufficiency, or those requiring high doses of trimethoprim. Amongst patients older than 65 years, concomitant use has been associated with a 2- to 7-fold increased risk of significant hyperkalemia compared to other antibiotics. Trimethoprim has a potassium-sparing effect on the distal nephron and may induce hyperkalemia, especially in those with pre-existing risk factors.
Sulfonylureas: (Moderate) Monitor blood glucose during concomitant sulfonylurea and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Sulindac: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Sumatriptan; Naproxen: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Suvorexant: (Major) A dose reduction to 5 mg of suvorexant is recommended during concurrent use with verapamil. The suvorexant dose may be increased to 10 mg if needed for efficacy. Suvorexant is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration with a moderate CYP3A4 inhibitor increased the suvorexant AUC by 2-fold.
Tacrolimus: (Moderate) Tacrolimus, in the absence of overt renal impairment, may adversely affect renal function. Care should be taken in using tacrolimus with other nephrotoxic drugs, including ACE inhibitors. (Moderate) Verapamil, a CYP3A4 substrate, may inhibit tacrolimus metabolism by inhibiting CYP3A4 intestinal metabolism. If verapamil is added to tacrolimus therapy, blood trough concentrations of tacrolimus should be monitored and dose adjustments may be necessary.
Tadalafil: (Moderate) Monitor for an increase in tadalafil-related adverse reactions if coadministration with verapamil is necessary. Tadalafil is a CYP3A4 substrate and verapamil is a moderate CYP3A inhibitor. Although specific interactions have not been studied, moderate CYP3A4 inhibitors would likely increase tadalafil exposure.
Talazoparib: (Major) Avoid coadministration of verapamil with talazoparib when used for the treatment of breast cancer due to increased talazoparib exposure. If concomitant use is unavoidable, reduce the dose of talazoparib to 0.75 mg PO once daily. If verapamil is discontinued, wait at least 3 to 5 half-lives of verapamil before increasing the dose of talazoparib to the prior dose used before verapamil therapy. A talazoparib dose reduction is not necessary for patients with prostate cancer; monitor for an increase in talazoparib-related adverse reactions. Talazoparib is a P-gp substrate and verapamil is a P-gp inhibitor. In clinical trials, coadministration with verapamil increased talazoparib exposure by 45%.
Tamsulosin: (Moderate) The concomitant administration of tamsulosin with other antihypertensive agents can cause additive hypotensive effects. In addition, diltiazem, nicardipine, and verapamil may increase tamsulosin plasma concentrations via CYP3A4 inhibition. This interaction can be therapeutically advantageous, but dosages must be adjusted accordingly.
Tasimelteon: (Moderate) Caution is recommended during concurrent use of tasimelteon and verapamil. Because tasimelteon is partially metabolized via CYP3A4, use with CYP3A4 inhibitors, such as verapamil, may increase exposure to tasimelteon with the potential for adverse reactions.
Tazemetostat: (Major) Avoid coadministration of tazemetostat with verapamil as concurrent use may increase tazemetostat exposure and the frequency and severity of adverse reactions. If concomitant use is unavoidable, decrease current tazemetostat daily dosage by 50% (e.g., decrease 800 mg PO twice daily to 400 mg PO twice daily; 600 mg PO twice daily to 400 mg PO for first dose and 200 mg PO for second dose; 400 mg PO twice daily to 200 mg PO twice daily). If verapamil is discontinued, wait at least 3 half-lives of verapamil before increasing the dose of tazemetostat to the previous tolerated dose. Tazemetostat is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration of another moderate CYP3A4 inhibitor increased tazemetostat exposure by 3.1-fold.
Telavancin: (Moderate) Concurrent or sequential use of telavancin with other potentially nephrotoxic drugs such as Angiotensin-converting enzyme inhibitors (ACE inhibitors) may lead to additive nephrotoxicity. Closely monitor renal function and adjust telavancin doses based on calculated creatinine clearance.
Telmisartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Telmisartan; Amlodipine: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy. (Moderate) Monitor for symptoms of hypotension and edema if coadministration of amlodipine with verapamil is necessary; adjust the dose of amlodipine as clinically appropriate. Amlodipine is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with a moderate CYP3A4 inhibitor in elderly hypertensive patients increased systemic exposure to amlodipine by 60%. However, coadministration with another moderate CYP3A4 inhibitor in healthy volunteers did not significantly change amlodipine exposure.
Telmisartan; Hydrochlorothiazide, HCTZ: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Temsirolimus: (Moderate) Monitor for signs and symptoms of angioedema if temsirolimus is administered concomitantly with trandolapril. Angioedema has been reported in patients taking mammalian target of rapamycin (mTOR) inhibitors in combination with another ACE inhibitor. (Moderate) Monitor for signs and symptoms of angioedema if temsirolimus is administered concomitantly with verapamil; an increase in treatment-related adverse reactions may also occur. Angioedema has been reported in patients taking mammalian target of rapamycin (mTOR) inhibitors in combination with another calcium channel blocker. Both drugs are also P-glycoprotein (P-gp) substrates and inhibitors. Concomitant use is likely to lead to increased concentrations of both temsirolimus and diltiazem.
Tenofovir Alafenamide: (Moderate) Coadministration of tenofovir alafenamide with verapamil may result in increased plasma concentrations of tenofovir leading to an increase in tenofovir-related adverse effects. Tenofovir alafenamide is a P-gp substrate and verapamil is a P-gp inhibitor.
Tenofovir Alafenamide: (Moderate) Coadministration of tenofovir alafenamide with verapamil may result in increased plasma concentrations of tenofovir leading to an increase in tenofovir-related adverse effects. Tenofovir alafenamide is a P-gp substrate and verapamil is a P-gp inhibitor.
Tenofovir Disoproxil Fumarate: (Moderate) Coadministration of tenofovir disoproxil fumarate with verapamil may result in increased plasma concentrations of tenofovir, leading to an increase in tenofovir-related adverse effects. Tenofovir disoproxil fumarate is a P-gp substrate and verapamil is a P-gp inhibitor.
Terazosin: (Moderate) The first-dose response (acute postural hypotension) of terazosin can be potentiated by coadministration with beta-blockers. The use of alpha-blockers with verapamil can lead to excessive hypotension; In addition, verapamil has been reported to increase the AUC and Cmax of prazosin and terazosin.
Terbinafine: (Moderate) Due to the risk for terbinafine related adverse effects, caution is advised when coadministering verapamil. Although this interaction has not been studied by the manufacturer, and published literature suggests the potential for interactions to be low, taking these drugs together may increase the systemic exposure of terbinafine. Predictions about the interaction can be made based on the metabolic pathways of both drugs. Terbinafine is metabolized by at least 7 CYP isoenzymes, with major contributions coming from CYP3A4; verapamil is an inhibitor of this enzyme. Monitor patients for adverse reactions if these drugs are coadministered.
Tetrabenazine: (Moderate) Tetrabenazine may induce orthostatic hypotension and thus enhance the hypotensive effects of antihypertensive agents. Lower initial doses or slower dose titration of tetrabenazine may be necessary in patients receiving antihypertensive agents concomitantly.
Tetracaine: (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents. Use extreme caution with the concomitant use of tetracaine and antihypertensive agents. (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents. Use extreme caution with the concomitant use of tetracaine and antihypertensive agents.
Tezacaftor; Ivacaftor: (Major) Adjust the tezacaftor; ivacaftor dosing schedule when coadministered with verapamil; coadministration may increase tezacaftor; ivacaftor exposure and adverse reactions. When combined, dose 1 tezacaftor; ivacaftor combination tablet every other day in the morning and 1 ivacaftor tablet every other day in the morning on alternate days (i.e., tezacaftor/ivacaftor tablet on Day 1 and ivacaftor tablet on Day 2). The evening dose of ivacaftor should not be taken. Both tezacaftor and ivacaftor are CYP3A substrates (ivacaftor is a sensitive substrate); verapamil is a moderate CYP3A inhibitor. Coadministration of a moderate CYP3A inhibitor increased ivacaftor exposure 3-fold. Simulation suggests a moderate inhibitor may increase tezacaftor exposure 2-fold. (Major) If verapamil and ivacaftor are taken together, administer ivacaftor at the usual recommended dose but reduce the frequency to once daily. Coadministration is not recommended in patients younger than 6 months. Ivacaftor is a CYP3A substrate and verapamil is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased ivacaftor exposure by 3-fold.
Thalidomide: (Moderate) Thalidomide and other agents that slow cardiac conduction such as calcium-channel blockers should be used cautiously due to the potential for additive bradycardia.
Theophylline, Aminophylline: (Moderate) Verapamil has been reported to decrease theophylline clearance. The mechanism is most likely reduced cytochrome P-450 metabolism of theophylline. Since the therapeutic range is narrow for theophylline, monitor theophylline serum concentrations during verapamil therapy. (Moderate) Verapamil may decrease aminophylline clearance due to reduced cytochrome P-450 metabolism of aminophylline. Since the therapeutic range is narrow for aminophylline, monitor serum concentrations during verapamil therapy.
Thiazide diuretics: (Major) Discontinue the thiazide diuretic prior to starting trandolapril, if possible, or start trandolapril at the lower dose of 0.5 mg/day. Monitor blood pressure, particularly when doses are increased, and renal function during concomitant use. Concomitant use may increase the risk for hypotension or renal failure.
Thiazolidinediones: (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Thiothixene: (Moderate) Thiothixene should be used cautiously in patients receiving antihypertensive agents. Additive hypotensive effects are possible.
Ticagrelor: (Moderate) Coadministration of ticagrelor and verapamil may result in increased exposure to ticagrelor which may increase the bleeding risk. Ticagrelor is a P-glycoprotein (P-gp) substrate and verapamil is a P-gp inhibitor. Based on drug information data with cyclosporine, no dose adjustment is recommended by the manufacturer of ticagrelor. Use combination with caution and monitor for evidence of bleeding.
Timolol: (Moderate) Use verapamil and timolol with caution and close monitoring due to risk for additive negative effects on heart rate, AV conduction, and/or cardiac contractility. There have been reports of excess bradycardia and AV block, including complete heart block, when beta-blockers and verapamil have been used for the treatment of hypertension.
Tipranavir: (Moderate) Verapamil is a substrate and inhibitor of CYP3A4, is a substrate of Pgp, and can prolong the PR interval; both pharmacokinetic and pharmacodynamic interactions may occur with tipranavir. Cautious dose titration of verapamil should be considered.
Tizanidine: (Major) Avoid concomitant use of tizanidine and verapamil as increased tizanidine exposure may occur. If use together is necessary, initiate tizanidine at 2 mg and increase by 2 to 4 mg/day based on clinical response. Discontinue tizanidine if hypotension, bradycardia, or excessive drowsiness occurs. Tizanidine is a CYP1A2 substrate and verapamil is a weak CYP1A2 inhibitor. (Moderate) Concurrent use of tizanidine with antihypertensive agents can result in significant hypotension. Caution is advised when tizanidine is to be used in patients receiving concurrent antihypertensive therapy.
Tolmetin: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Tolterodine: (Moderate) In a small portion of patients who poorly metabolize tolterodine via CYP2D6, the CYP3A4 pathway becomes important in tolterodine elimination. Verapamil is a CYP3A4 inhibitor. Pharmacokinetic studies of the use of tolterodine concomitantly with CYP3A4 inhibitors have not been performed. Because it is difficult to assess which patients will be poor metabolizers of tolterodine via CYP2D6, those patients receiving CYP3A4 inhibitors should not receive more than 2 mg/day of tolterodine.
Tolvaptan: (Major) Avoid coadministration of verapamil when tolvaptan is administered for hyponatremia. In patients with autosomal dominant polycystic kidney disease (ADPKD), reduce tolvaptan dosage if administered with verapamil. In ADPKD patients receiving tolvaptan 90mg every morning and 30 mg every evening, reduce the dose to 45 mg every morning and 15 mg every evening; for those receiving tolvaptan 60 mg every morning and 30 mg every evening, reduce the dose to 30 mg every morning and 15 mg every evening; for those receiving tolvaptan 45 mg every morning and 15 mg every evening, reduce the dose to 15 mg every morning and 15 mg every evening. Consider additional dosage reduction if the reduced dose is not tolerated. Tolvaptan is a sensitive CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. Coadministration of another moderate CYP3A4 inhibitor increased the tolvaptan AUC by 200%. (Moderate) Monitor serum potassium concentrations closely if tolvaptan and angiotensin-converting enzyme inhibitors (ACE inhibitors) are used together. In clinical studies, hyperkalemia was reported at a rate 1% to 2% higher when tolvaptan was administered with ACE inhibitors compared to administration of these medications with placebo.
Topotecan: (Major) Avoid coadministration of verapamil with oral topotecan due to increased topotecan exposure; verapamil may be administered with intravenous topotecan. Oral topotecan is a substrate of P-glycoprotein (P-gp) and verapamil is a P-gp inhibitor. Oral administration within 4 hours of another P-gp inhibitor increased the dose-normalized AUC of topotecan lactone and total topotecan 2-fold to 3-fold compared to oral topotecan alone.
Tranylcypromine: (Contraindicated) The use of hypotensive agents and tranylcypromine is contraindicated by the manufacturer of tranylcypromine because the effects of hypotensive agents may be markedly potentiated. (Major) Avoid concomitant use of calcium-channel blockers and tranylcypromine due to the risk of additive hypotension. Potential for this interaction persists for up to 10 days after discontinuation of tranylcypromine (or 4 to 5 half-lives after discontinuation of the calcium-channel blocker). If a medication-free interval is not feasible, initiate therapy at the lowest appropriate dose and monitor blood pressure closely.
Trazodone: (Minor) Due to additive hypotensive effects, patients receiving antihypertensive agents concurrently with trazodone may have excessive hypotension. Decreased dosage of the antihypertensive agent may be required when given with trazodone. (Minor) Due to additive hypotensive effects, patients receiving antihypertensive agents concurrently with trazodone may have excessive hypotension. Decreased dosage of the antihypertensive agent may be required when given with trazodone.
Treprostinil: (Moderate) Calcium-channel blockers can have additive hypotensive effects with other antihypertensive agents. This additive effect can be desirable, but the patient should be monitored carefully and the dosage should be adjusted based on clinical response.
Triamterene: (Moderate) Monitor serum potassium concentrations closely if ACE inhibitors and triamterene are used together. Concomitant use may increase the risk of hyperkalemia, especially in elderly patients or patients with impaired renal function.
Triamterene; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum potassium concentrations closely if ACE inhibitors and triamterene are used together. Concomitant use may increase the risk of hyperkalemia, especially in elderly patients or patients with impaired renal function.
Triazolam: (Moderate) Monitor for signs of triazolam toxicity during coadministration with verapamil and consider appropriate dose reduction of triazolam if clinically indicated. Coadministration may increase triazolam exposure. Triazolam is a sensitive CYP3A substrate and verapamil is a moderate CYP3A inhibitor.
Trimethoprim: (Moderate) Monitor for hyperkalemia if concomitant use of an angiotensin-converting enzyme (ACE) inhibitor and trimethoprim is necessary. Avoid concomitant use and consider alternative antibiotic therapy in patients with additional risk factors for hyperkalemia, including patients older than 65 years, those with underlying disorders of potassium metabolism, renal insufficiency, or those requiring high doses of trimethoprim. Amongst patients older than 65 years, concomitant use has been associated with a 2- to 7-fold increased risk of significant hyperkalemia compared to other antibiotics. Trimethoprim has a potassium-sparing effect on the distal nephron and may induce hyperkalemia, especially in those with pre-existing risk factors.
Triptorelin: (Major) Avoid coadministration of triptorelin with verapamil due to the risk of reduced efficacy of triptorelin. Verapamil can cause hyperprolactinemia, which reduces the number of pituitary gonadotropin releasing hormone (GnRH) receptors; triptorelin is a GnRH analog.
Tucatinib: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with tucatinib. Coadministration may increase the exposure of verapamil. Tucatinib is a strong inhibitor of CYP3A4; verapamil is a substrate of CYP3A4.
Ubrogepant: (Major) Limit the initial dose of ubrogepant to 50 mg and avoid a second dose within 24 hours if coadministered with verapamil. Concurrent use may increase ubrogepant exposure and the risk of adverse effects. Ubrogepant is a CYP3A4 and P-gp substrate; verapamil is a moderate CYP3A4 inhibitor and a P-gp inhibitor. Coadministration with verapamil resulted in a 3.5-fold increase in the exposure of ubrogepant.
Umeclidinium: (Moderate) Umeclidinium is a P-gp substrate. When verapamil, a moderate P-gp transporter inhibitor, was given to healthy adult subjects at a dose of 240 mg once daily in combination with umeclidinium, no effect on umeclidinium Cmax was observed. However, an approximately 1.4-fold increase in umeclidinium AUC was observed.
Umeclidinium; Vilanterol: (Moderate) Umeclidinium is a P-gp substrate. When verapamil, a moderate P-gp transporter inhibitor, was given to healthy adult subjects at a dose of 240 mg once daily in combination with umeclidinium, no effect on umeclidinium Cmax was observed. However, an approximately 1.4-fold increase in umeclidinium AUC was observed.
Valdecoxib: (Moderate) If nonsteroidal anti-inflammatory drugs (NSAIDs) and an antihypertensive drug are concurrently used, carefully monitor the patient for signs and symptoms of renal insufficiency and blood pressure control. Doses of antihypertensive medications may require adjustment in patients receiving concurrent NSAIDs. NSAIDs, to varying degrees, have been associated with an elevation in blood pressure. This effect is most significant in patients receiving concurrent antihypertensive agents and long-term NSAID therapy. NSAIDs cause a dose-dependent reduction in prostaglandin formation, which may result in a reduction in renal blood flow leading to renal insufficiency and an increase in blood pressure that are often accompanied by peripheral edema and weight gain. Patients who rely upon renal prostaglandins to maintain renal perfusion may have acute renal blood flow reduction with NSAID usage. Elderly patients may be at increased risk of adverse effects from combined long-term NSAID therapy and antihypertensive agents, especially diuretics, due to age-related decreases in renal function and an increased risk of stroke and coronary artery disease.
Valsartan: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Valsartan; Hydrochlorothiazide, HCTZ: (Major) In general, avoid combined use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) due to lack of benefit with concomitant use in most patients. Closely monitor blood pressure, renal function, and electrolytes in patients on ACE inhibitors and ARBs. Dual blockade of the renin-angiotensin system with ACE inhibitors and ARBs is associated with increased risks of hypotension, syncope, hyperkalemia, and changes in renal function, including acute renal failure, compared to monotherapy.
Vardenafil: (Major) Do not use vardenafil orally disintegrating tablets with verapamil due to increased vardenafil exposure; do not exceed a single dose of 5 mg per 24-hour period of vardenafil oral tablets. Additive hypotensive effects are also possible. Vardenafil is primarily metabolized by CYP3A and verapamil is a moderate CYP3A inhibitor. Coadministration with another moderate CYP3A inhibitor increased the AUC of vardenafil by 4-fold.
Vemurafenib: (Moderate) Concomitant use of vemurafenib and verapamil may result in altered concentrations of verapamil and increased concentrations of vemurafenib. Vemurafenib is a substrate/inducer of CYP3A4, a substrate/inhibitor of P-glycoprotein (PGP), and an inhibitor of CYP1A2 and CYP2C9. Verapamil is a substrate/inhibitor of CYP3A4 and PGP and a substrate of CYP1A2 and CYP2C9. Use caution and monitor patients for toxicity and efficacy.
Venetoclax: (Major) Reduce the dose of venetoclax by at least 50% and monitor for venetoclax toxicity (e.g., hematologic toxicity, GI toxicity, and tumor lysis syndrome) if coadministered with verapamil due to the potential for increased venetoclax exposure. Resume the original venetoclax dose 2 to 3 days after discontinuation of verapamil. Venetoclax is a CYP3A4 and P-glycoprotein (P-gp) substrate; verapamil is a CYP3A4 (moderate) and P-gp inhibitor. Coadministration with a single dose of another P-gp inhibitor increased venetoclax exposure by 78% in a drug interaction study.
Verteporfin: (Moderate) Use caution if coadministration of verteporfin with calcium channel blockers is necessary due to the risk of increased photosensitivity. Verteporfin is a light-activated drug used in photodynamic therapy; all patients treated with verteporfin will be photosensitive. Concomitant use with calcium channel blockers could enhance the rate of verteporfin uptake by the vascular endothelium, resulting in enhanced photosensitivity.
Vinblastine: (Moderate) Monitor for an earlier onset and/or increased severity of vinblastine-related adverse reactions, including myelosuppression, constipation, and peripheral neuropathy, if coadministration with verapamil is necessary. Vinblastine is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Enhanced vinblastine toxicity was reported with coadministration of another moderate CYP3A4 inhibitor.
Vincristine Liposomal: (Major) Verapamil inhibits CYP3A4 and P-glycoprotein (P-gp); vincristine is a CYP3A and P-gp substrate. Coadministration could increase exposure to vincristine; however, verapamil must be given in toxic doses to achieve this effect. An in vitro study has shown that verapamil competes with vincristine for protein binding sites, specifically 1-acid glycoprotein. Verapamil reduced the binding of vincristine to various proteins by 27 to 60%. The clinical significance of this interaction is not known. The absorption of verapamil may also be reduced by coadministration with the cyclophosphamide, vincristine, procarbazine, prednisone (COPP) chemotherapeutic drug regimen. Monitor for increased side effects of vincristine and loss of blood pressure control during coadministration.
Vincristine: (Major) Verapamil inhibits CYP3A4 and P-glycoprotein (P-gp); vincristine is a CYP3A and P-gp substrate. Coadministration could increase exposure to vincristine; however, verapamil must be given in toxic doses to achieve this effect. An in vitro study has shown that verapamil competes with vincristine for protein binding sites, specifically 1-acid glycoprotein. Verapamil reduced the binding of vincristine to various proteins by 27 to 60%. The clinical significance of this interaction is not known. The absorption of verapamil may also be reduced by coadministration with the cyclophosphamide, vincristine, procarbazine, prednisone (COPP) chemotherapeutic drug regimen. Monitor for increased side effects of vincristine and loss of blood pressure control during coadministration.
Vinorelbine: (Moderate) Monitor for an earlier onset and/or increased severity of vinorelbine-related adverse reactions, including constipation and peripheral neuropathy, if coadministration with verapamil is necessary. Vinorelbine is a CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor.
Voclosporin: (Major) Reduce the voclosporin dosage to 15.8 mg PO in the morning and 7.9 mg PO in the evening if coadministered with verapamil. Concomitant use may increase voclosporin exposure and the risk of voclosporin-related adverse effects such as nephrotoxicity, hypertension, and QT prolon gation. Voclosporin is a sensitive CYP3A4 substrate and verapamil is a moderate CYP3A4 inhibitor. Coadministration with verapamil increased voclosporin exposure by 2.7-fold.
Vonoprazan; Amoxicillin; Clarithromycin: (Major) Avoid coadministration of clarithromycin and verapamil, particularly in geriatric patients, due to an increased risk of hypotension and acute kidney injury. If the use of a macrolide antibiotic is necessary in a patient receiving verapamil therapy, azithromycin is the preferred agent. If coadministration is unavoidable, monitor blood pressure closely. Verapamil is a CYP3A4 substrate and clarithromycin is a strong CYP3A4 inhibitor. A retrospective, case crossover study, found the risk of hospitalization due to hypotension or shock to be significantly increased in geriatric patients exposed to clarithromycin during concurrent calcium-channel blocker therapy (OR 3.7, 95% CI 2.3-6.1). Concurrent use of azithromycin was not associated with an increased risk of hypotension (OR 1.5, 95% CI 0.8-2.8). One case of a possible verapamil-clarithromycin interaction was reported, which was associated with hypotension.
Vorapaxar: (Moderate) Use caution during concurrent use of vorapaxar and verapamil. Increased serum concentrations of vorapaxar are possible when vorapaxar, a CYP3A4 substrate, is coadministered with verapamil, a CYP3A inhibitor. Increased exposure to vorapaxar may increase the risk of bleeding complications.
Voriconazole: (Moderate) Monitor blood pressure and heart rate if coadministration of verapamil with voriconazole is necessary. Concurrent use may result in elevated verapamil concentrations. Verapamil is a CYP3A4 substrate and voriconazole is a strong CYP3A4 inhibitor.
Voxelotor: (Moderate) Monitor blood pressure and heart rate during coadministration of verapamil with voxelotor. Coadministration may increase the exposure of verapamil. Voxelotor is a moderate inhibitor of CYP3A; verapamil is a substrate of CYP3A.
Warfarin: (Moderate) Closely monitor the INR if coadministration of warfarin with verapamil is necessary as concurrent use may increase the exposure of warfarin leading to increased bleeding risk. Verapamil is a CYP1A2 and moderate CYP3A4 inhibitor and warfarin is a CYP1A2/CYP3A4 substrate.
Zafirlukast: (Minor) Caution should be used when CYP3A4 inhibitors are co-administered with verapamil, a CYP3A4 substrate and inhibitor. This combination may cause reduced metabolism and increased effect of verapamil.
Zanubrutinib: (Major) Decrease the zanubrutinib dose to 80 mg PO twice daily if coadministered with verapamil. Coadministration may result in increased zanubrutinib exposure and toxicity (e.g., infection, bleeding, and atrial arrhythmias). Further decrease the zanubrutinib dose as recommended if adverse reactions occur. After discontinuation of verapamil, resume the previous dose of zanubrutinib. Zanubrutinib is a CYP3A4 substrate; verapamil is a moderate CYP3A4 inhibitor. The AUC of zanubrutinib is predicted to increase by 157% to 317% when coadministered with other moderate CYP3A4 inhibitors.
Ziprasidone: (Major) Verapamil may reduce ziprasidone metabolism via inhibition of CYP3A4 isoenzymes. (Minor) Ziprasidone is a moderate antagonist of alpha-1 receptors and may cause orthostatic hypotension with or without tachycardia, dizziness, or syncope. Additive hypotensive effects are possible if ziprasidone is used concurrently with antihypertensive agents.
Zonisamide: (Minor) Zonisamide is a weak inhibitor of P-glycoprotein (P-gp), and verapamil is a substrate of P-gp. There is theoretical potential for zonisamide to affect the pharmacokinetics of drugs that are P-gp substrates. Use caution when starting or stopping zonisamide or changing the zonisamide dosage in patients also receiving drugs that are P-gp substrates.

How Supplied

Tarka/Trandolapril, Verapamil/Trandolapril, Verapamil Hydrochloride Oral Tab ER: 1-240mg, 2-180mg, 2-240mg, 4-240mg

Maximum Dosage
Adults

8 mg/day PO trandolapril and 240 mg/day PO verapamil.

Elderly

8 mg/day PO trandolapril and 240 mg/day PO verapamil.

Adolescents

Safety and efficacy have not been established.

Children

Safety and efficacy have not been established.

Mechanism Of Action

Mechanism of Action: The effects of trandolapril and verapamil on blood pressure are approximately additive. The combination demonstrates greater antihypertensive and antiproteinuric effects than either agent alone. Trandolapril lowers blood pressure by blocking the renin-angiotensin system; whereas verapamil lowers systemic blood pressure by decreasing vascular resistance.•Trandolapril: Trandolapril is an oral, non-sulfhydryl-containing angiotensin converting enzyme inhibitor (ACEI). Trandolapril is hydrolyzed to trandolaprilat, which is about 8 times as potent as trandolapril in inhibiting ACE. Trandolaprilat, the active metabolite of trandolapril, competes with angiotensin I for its binding site on the angiotensin-converting enzyme (ACE). As a result, the drug blocks the conversion of angiotensin I to angiotensin II. Angiotensin II is a potent vasoconstrictor and a negative feedback mediator for renin activity. Thus, trandolapril decreases angiotensin II plasma levels, decreases blood pressure and increases plasma renin activity. In addition, baroreceptor reflex mechanisms are stimulated in response to the fall in blood pressure. Kininase II, identical to ACE, is an enzyme that degrades bradykinin, a potent vasodilator, to inactive peptides. Whether increased bradykinin levels play a part in the therapeutic effects of ACE inhibitors is presently unclear. Bradykinin-induced vasodilation is thought to be of secondary importance in the blood-pressure lowering effect of ACE inhibitors. A bradykinin mechanism may, however, contribute to ACE-inhibitor-induced angioneurotic edema.ACE-inhibiting drugs can act locally to reduce vascular tone by decreasing local angiotensin II-induced sympathetic and/or vasoconstrictive activity. ACE inhibitors also can inhibit presynaptic norepinephrine release and postsynaptic adrenergic receptor activity, thus decreasing vascular sensitivity to vasopressor activity; however, this action may not be clinically evident at usual doses. Decreases in plasma angiotensin II levels also result in a reduction in aldosterone secretion, with a subsequent decrease in sodium and water retention.Trandolapril causes arterial dilation, thereby lowering total peripheral vascular resistance. In hypertensive patients, blood pressure is decreased with little or no change in heart rate, stroke volume, or cardiac output. Both standing and supine blood pressure are reduced following administration of trandolapril, and although symptomatic hypotension is rare, it occurs more commonly in patients who are hypovolemic or hyponatremic. As with other ACE inhibitors, trandolapril is less effective in reducing blood pressure in the black population than in non-black population. As antihypertensives, ACE inhibitors reduce left ventricular hypertrophy (LVH), do not worsen insulin resistance or hyperlipidemia, and do not cause sexual dysfunction.•Verapamil: Verapamil is a phenylalkylamine calcium-channel blocker that exerts its pharmacologic effects by modulating the influx of ionic calcium across the cell membrane of the arterial smooth muscle as well as within conductile and contractile myocardial cells. Verapamil exerts antihypertensive effects by decreasing systemic vascular resistance, usually without orthostatic decreases in blood pressure or reflex tachycardia. Serum calcium levels remain unchanged. Inhibition of smooth muscle contraction also results in dilation of coronary and systemic arteries. Verapamil increases oxygen delivery to the myocardial tissue and decreases total peripheral resistance, systemic blood pressure, and afterload. Verapamil may reduce myocardial contractility; however, this action is often countered by a reduction of afterload, resulting in no overall change in cardiac index in patients without left ventricular dysfunction.Verapamil exerts equipotent effects on calcium channels in SA and AV nodes, and on the peripheral vasculature, however, verapamil is less potent as a peripheral vasodilator than nifedipine and related dihydropyridine analogs. By decreasing the influx of calcium, verapamil prolongs the effective refractory period within the AV node, prolongs the PR interval on the ECG, and slows AV conduction and heart rate. Second- or third-degree heart block may occur, especially in patients receiving beta-blockers (see Contraindications). Normal sinus rhythm is usually not affected, but in patients with sick sinus syndrome, verapamil may interfere with sinus node impulse generation.In general, calcium-channel blockers exert favorable effects on left ventricular hypertrophy, and do not worsen insulin resistance or exert detrimental effects on the lipid profile.

Pharmacokinetics

Trandolapril; verapamil is administered orally. The pharmacokinetics of trandolapril or trandolaprilat are not changed by coadministration with verapamil. However, the AUC and Cmax for both verapamil and norverapamil are increased when 240 mg of extended-release verapamil is administered concomitantly with 4 mg of trandolapril; the increase in Cmax is 54 and 30% and the AUC is increased by 65 and 32% for verapamil and norverapamil, respectively.
 
•Trandolapril: Trandolapril is metabolized to an active metabolite, trandolaprilat, which is about 8 times more potent as an ACE inhibitor. The absolute bioavailability is approximately 10% as trandolapril and 70% as trandolaprilat. The plasma protein binding of trandolapril is about 80% and is independent of concentration, whereas the binding of trandolaprilat is concentration-dependent. The lipophilicity index is highest for trandolaprilat when compared to captopril, enalaprilat, or ramiprilat. Trandolapril is deesterified to trandolaprilate by the liver. About 33% of the parent drug and metabolites are excreted in the urine, mostly as trandolaprilat. Fecal excretion accounts for about 65% of the dose. Less than 1% of the dose is excreted in the urine as unchanged drug. The extent of absorbed dose which is excreted by the biliary route has not been determined. The elimination half-lives of trandolapril and trandolaprilat are about 6 and 10 hours, respectively.
 
•Verapamil: Oral verapamil is a racemic mixture. Hepatic enzyme-inducing drugs or hepatic disease can significantly alter the bioavailability. Verapamil and its active and primary metabolite norverapamil are well distributed throughout the body including the CNS. It is excreted into breast milk, reaching concentrations which approach those in maternal serum. Verapamil readily crosses the placenta. Approximately 90% of the drug is bound to plasma proteins. About 70% of a dose is excreted renally as metabolites. Although verapamil is extensively metabolized in the liver to 12 metabolites, only norverapamil is detectable in the serum to any great extent. Norverapamil possesses approximately 20% of the pharmacologic activity of the parent compound. Norverapamil is a vasodilator, which lacks effects on the heart rate or P-R interval. The first-pass metabolism of verapamil is stereoselective, with preferential metabolism of the l-isomer. The elimination half-life of verapamil averages 2—5 hours following single doses of the drug and increases with chronic dosing to 5—12 hours. The half-life is also prolonged to approximately 14 hours in patients with hepatic impairment. The half-life of norverapamil ranges 4—10 hours. Elimination occurs primarily via renal pathways (70%), and 16% of the drug is eliminated in the feces within 5 days. Less than 5% of the drug is excreted in the urine as the parent compound.
 
Affected cytochrome P450 isoenzymes and drug transporters: CYP3A4, CYP1A2, CYP2C8, CYP2C9, and CYP2C18, P-gp
In vitro metabolic studies indicate that verapamil is metabolized by CYP3A4, CYP1A2, CYP2C8, CYP2C9, and CYP2C18. Clinically significant interactions have been reported with inducers or inhibitors of CYP3A4; therefore, patients receiving verapamil should be monitored closely for drug interactions. In addition, verapamil inhibits CYP3A4 isoenzymes. It is also a substrate and inhibitor of P-glycoprotein.[56565]

Oral Route

Following a single oral dose of Tarka, peak plasma concentrations are reached within 0.5—2 hours for trandolapril, 2—12 hours for trandolaprilat, 4—15 hours for verapamil and 5—15 hours for norverapamil. Administration of Tarka with a high fat meal does not alter the bioavailability of trandolapril, but does reduce verapamil bioavailability. Food (high-fat meal) decreases verapamil bioavailability by 28% and also reduces peak plasma verapamil concentrations by 37%. In addition, the time to peak plasma concentrations for both verapamil (both isomers) and norverapamil are delayed by approximately 7 hours.
 
•Trandolapril: Trandolapril is rapidly absorbed.
 
•Verapamil: Oral verapamil is a racemic mixture. Verapamil is rapidly and well absorbed (90%) following an oral dose. Following oral administration, verapamil undergoes extensive first-pass metabolism, resulting in a bioavailability of 20—35%. A nonlinear correlation exists between verapamil dose and plasma concentrations. Co-administration with grapefruit juice increases the bioavailability and plasma concentrations of verapamil.

Pregnancy And Lactation
Pregnancy

Drugs that affect the renin-angiotensin system (e.g., ACE inhibitors, angiotensin II receptor antagonists) reduce fetal renal function and increase fetal and neonatal morbidity and death when used during the second and third trimesters. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Other potential neonatal adverse effects include skull hypoplasia, anuria, and hypotension. Counsel females of child-bearing age on the consequences of trandolapril; verapamil exposure during pregnancy and discuss treatment options with those planning to become pregnant. Discontinue trandolapril; verapamil as soon as pregnancy is detected. In rare cases when another antihypertensive agent cannot be used to treat a pregnant patient, serial ultrasound examinations should be performed to assess the intraamniotic environment. If oligohydramnios is observed, discontinue trandolapril; verapamil unless it is considered life-saving for the mother. It should be noted that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe newborns with histories of in utero exposure to trandolapril; verapamil for hypotension, oliguria, and hyperkalemia. If oliguria or hypotension occurs, blood pressure and renal perfusion support may be required, as well as exchange transfusion or dialysis to reverse hypotension and/or support decreased renal function. Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensives in the first trimester have not distinguished between antihypertensive mechanism.[35075] Retrospective data indicate that first trimester use of ACE inhibitors has been associated with a potential risk of birth defects.[32294] However, a large observational study (n = 465,754) found that the risk of birth defects was similar in infants exposed to ACE inhibitors during the first trimester, in infants exposed to other antihypertensives during the first trimester, and in those whose mothers were hypertensive but were not treated.[46406] Infants born to mothers with hypertension, either treated or untreated, had a higher risk of birth defects than those born to mothers without hypertension. The authors concluded that the presence of hypertension likely contributed to the development of birth defects rather than the use of medications.

Do not administer trandolapril; verapamil to breast-feeding mothers as verapamil is excreted in human milk. Verapamil was previously considered usually compatible with breast-feeding by the American Academy of Pediatrics (AAP); limited data suggest low infant exposure (less than 0.01% to 0.1% of the maternally ingested verapamil dose) and there is a lack of reported adverse effects. Alternative therapies may be considered. Due to low levels in breast milk, guidelines generally consider the ACE inhibitors captopril and enalapril to be compatible with breast-feeding unless high doses are required. In addition, benazepril and quinapril are excreted in low quantities into breast milk and have been suggested as options during breast-feeding. Only small quantities of the calcium channel blocker nifedipine is excreted into breast milk; therefore, it is generally considered safe during breast-feeding. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition.