Hytrin

Alpha Adrenoreceptor Antagonists/Alpha Blockers
Alpha-Blockers

 
NOTE: If terazosin therapy is interrupted for several days, restart therapy with initial dosing regimen.

Terazosin may be administered without regard to meals. Food may delay the time to peak concentrations, but has no significant effect on terazosin bioavailability.
 
In patients with feeding tubes:
NOTE: Terazosin binds to the soft-gelatin capsule in which it is formulated making it difficult to completely extract the contents when the liquid is squeezed from the capsule. The following strategy has been recommended as an alternative method of oral administration in patients with feeding tubes:
Place the capsule in a cup containing 60 ml of warm tap water (100—110 degrees F). Stir until the liquid in the capsule spills from the ruptured shell (about 5 minutes). Continue stirring until the capsule dissolves and the solution is homogeneous (5—10 minutes). The solution color depends on the color of the capsule. Draw the solution into an oral syringe and administer through the feeding tube. Flush the tube with water following administration.

atrial fibrillation / Early / Incidence not known
visual impairment / Early / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known

peripheral edema / Delayed / 0.9-5.5
palpitations / Early / 4.3-4.3
orthostatic hypotension / Delayed / 1.3-3.9
dyspnea / Early / 1.7-3.1
sinus tachycardia / Rapid / 1.9-1.9
impotence (erectile dysfunction) / Delayed / 1.6-1.6
blurred vision / Early / 1.3-1.6
amblyopia / Delayed / 1.3-1.3
edema / Delayed / 0.9-0.9
depression / Delayed / 0.3-0.3
chest pain (unspecified) / Early / Incidence not known
peripheral vasodilation / Rapid / Incidence not known
constipation / Delayed / Incidence not known
priapism / Early / Incidence not known
urinary incontinence / Early / Incidence not known
floppy iris syndrome / Delayed / Incidence not known
conjunctivitis / Delayed / Incidence not known
gout / Delayed / Incidence not known
thrombocytopenia / Delayed / Incidence not known

dizziness / Early / 9.1-19.3
headache / Early / 16.2-16.2
asthenia / Delayed / 7.4-11.3
nasal congestion / Early / 1.9-5.9
drowsiness / Early / 3.6-5.4
nausea / Early / 1.7-4.4
paresthesias / Delayed / 2.9-2.9
sinusitis / Delayed / 2.6-2.6
influenza / Delayed / 2.4-2.4
back pain / Delayed / 2.4-2.4
anxiety / Delayed / 2.3-2.3
rhinitis / Early / 1.9-1.9
vertigo / Early / 1.4-1.4
syncope / Early / 0.6-0.6
libido decrease / Delayed / 0.6-0.6
weight gain / Delayed / 0.5-0.5
arthralgia / Delayed / 1.0
myalgia / Early / 1.0
arthropathy / Delayed / 1.0
insomnia / Early / Incidence not known
vomiting / Early / Incidence not known
xerostomia / Early / Incidence not known
diarrhea / Early / Incidence not known
flatulence / Early / Incidence not known
abdominal pain / Early / Incidence not known
dyspepsia / Early / Incidence not known
increased urinary frequency / Early / Incidence not known
infection / Delayed / Incidence not known
epistaxis / Delayed / Incidence not known
cough / Delayed / Incidence not known
pharyngitis / Delayed / Incidence not known
tinnitus / Delayed / Incidence not known
fever / Early / Incidence not known
pruritus / Rapid / Incidence not known
rash / Early / Incidence not known
hyperhidrosis / Delayed / Incidence not known

Hytrin

Rx

Alpha-adrenergic blocker; used for HTN and BPH; duration of action longer than prazosin but is shorter than doxazosin; greater efficacy for BPH when compared to finasteride.

1 mg PO once daily at bedtime, initially. Usual dose range: 1 to 20 mg/day in 1 or 2 divided doses. Max: 20 mg/day.

1 mg PO once daily, initially. May increase the dose to 2 mg, 5 mg, and then 10 mg PO once daily based on clinical response. Usual dose: 10 mg/day. Some may not achieve a clinical response despite appropriate titration. Although some responded at a dose of 20 mg/day, there was an insufficient number of subjects studied to draw definitive conclusions about this dose. There are insufficient data to support the use of higher doses for those who show inadequate or no response to 20 mg/day. If therapy is interrupted for several days, restart at 1 mg PO once daily.

No specific recommendations are available for hepatic disease. Since terazosin is extensively metabolized, it is prudent to start with the lowest initial adult dosage (1 mg PO once daily at bedtime). Monitor and adjust dosage based on clinical response.

No dosage adjustment is needed.
 
Intermittent hemodialysis
No dosage adjustment is needed. Terazosin is highly protein bound and only 10% is removed during hemodialysis, and supplemental doses are not needed.

Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Acetaminophen; Dextromethorphan; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Acetaminophen; Dichloralphenazone; Isometheptene: (Major) Sympathomimetics can antagonize the antihypertensive effects of adrenergic agonists when administered concomitantly. Patients should be monitored for loss of blood pressure control.
Acetaminophen; Guaifenesin; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Acetaminophen; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Acetaminophen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Acrivastine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Aldesleukin, IL-2: (Moderate) Terazosin 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.
Alfuzosin: (Major) Alfuzosin should not be administered in combination with other alpha-blockers. The pharmacokinetic and pharmacodynamic interactions between alfuzosin and other alpha-blockers (used for high blood pressure or for benign prostatic hyperplasia) have not been determined. However, interactions or side effects (dizziness, hypotension, syncope, etc.) may be expected from the duplication of pharmacologic effects.
Alprostadil: (Minor) The concomitant use of systemic alprostadil injection and antihypertensive agents, such as terazosin, 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.
Amifostine: (Major) Patients receiving alpha-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, patients should not receive amifostine.
Amobarbital: (Moderate) Concurrent use of amobarbital with antihypertensive agents may lead to hypotension. Monitor for decreases in blood pressure during times of coadministration.
Amphetamines: (Minor) Close monitoring of blood pressure or the selection of alternative therapeutic agents may be needed in patients receiving terazosin and amphetamines. Amphetamines increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, such as terazosin.
Apomorphine: (Moderate) Use of terazosin 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.
Aripiprazole: (Minor) Aripiprazole may enhance the hypotensive effects of antihypertensive agents.
Articaine; Epinephrine: (Moderate) Alpha-blockers antagonize the pressor effects of epinephrine. Do not use epinephrine to counteract hypotension caused by an alpha-blocker, as a reversal of the pressor effect of epinephrine may result in paradoxical further lowering of blood pressure.
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.
Avanafil: (Moderate) Due to the potential for symptomatic hypotension, patients should be stable on alpha-blocker therapy before initiating therapy with the lowest dose of avanafil. Conversely, patients already receiving an optimized dose of avanafil should be started on the lowest dose of the alpha-blocker; increases in the alpha-blocker dose should be done in a stepwise fashion. Other variables, such as intravascular volume depletion, concurrent antihypertensive therapy, or evidence of hemodynamic instability with alpha-blocker monotherapy, may affect the safety of concomitant use of avanafil and alpha-blockers.
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.
Beta-blockers: (Moderate) Orthostatic hypotension may be more likely if beta-blockers are coadministered with alpha-blockers.
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.
Brexpiprazole: (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.
Brompheniramine; Dextromethorphan; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Brompheniramine; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Brompheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Bupivacaine; Epinephrine: (Moderate) Alpha-blockers antagonize the pressor effects of epinephrine. Do not use epinephrine to counteract hypotension caused by an alpha-blocker, as a reversal of the pressor effect of epinephrine may result in paradoxical further lowering of blood pressure.
Cabergoline: (Moderate) Cabergoline should be used cautiously with antihypertensive agents, including alpha-blockers. Cabergoline has been associated with hypotension. Initial doses higher than 1 mg may produce orthostatic hypotension. It may be advisable to monitor blood pressure.
Cariprazine: (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.
Cetirizine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Chlorpheniramine; Dextromethorphan; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Chlorpheniramine; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Chlorpheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Codeine; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Codeine; Phenylephrine; Promethazine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
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.
Desloratadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Desogestrel; Ethinyl Estradiol: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Dexbrompheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Dextromethorphan; Diphenhydramine; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Dextromethorphan; Guaifenesin; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Dextromethorphan; Quinidine: (Moderate) Quinidine can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents due to the potential for additive hypotension.
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.
Diethylpropion: (Major) Diethylpropion has vasopressor effects and may limit the benefit of alpha-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.
Diphenhydramine; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Dobutamine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Dopamine: (Major) In general, alpha-blockers should not be used during dopamine infusion. The undesired peripheral vasoconstriction observed with high-dose dopamine is opposed by alpha-adrenergic blockers. The renal, mesenteric, or cerebral vasodilatory properties resulting from dopaminergic-receptor stimulation are not affected by alpha-blockers .
Drospirenone; Ethinyl Estradiol: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Drospirenone; Ethinyl Estradiol; Levomefolate: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
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: (Major) Tamsulosin should not be administered in combination with other alpha-blockers. The pharmacokinetic and pharmacodynamic interactions between tamsulosin and other alpha-blockers (used for high blood pressure or for benign prostatic hyperplasia) have not been determined. However, interactions or side effects (dizziness, hypotension, syncope, etc.) may be expected from the duplication of pharmacologic effects.
Ephedrine: (Moderate) Carefully monitor blood pressure in patients who have received both ephedrine and alpha-blockers; alpha-blockers antagonize the pressor effect of ephedrine.
Ephedrine; Guaifenesin: (Moderate) Carefully monitor blood pressure in patients who have received both ephedrine and alpha-blockers; alpha-blockers antagonize the pressor effect of ephedrine.
Epinephrine: (Moderate) Alpha-blockers antagonize the pressor effects of epinephrine. Do not use epinephrine to counteract hypotension caused by an alpha-blocker, as a reversal of the pressor effect of epinephrine may result in paradoxical further lowering of blood pressure.
Epoprostenol: (Minor) Epoprostenol can have additive effects when administered with other antihypertensive agents, including alpha-blockers. These effects can be used to therapeutic advantage, but dosage adjustments may be necessary.
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 to confirm that the desired antihypertensive effect is being obtained.
Ethanol: (Major) Advise patients to avoid alcohol consumption while taking alpha-blockers. Concomitant use may increase the risk for hypotension.
Ethinyl Estradiol; Norelgestromin: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Ethinyl Estradiol; Norethindrone Acetate: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Ethinyl Estradiol; Norgestrel: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Ethynodiol Diacetate; Ethinyl Estradiol: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Etomidate: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Etonogestrel; Ethinyl Estradiol: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Fexofenadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Finasteride: (Minor) Terazosin has been reported to increase peak concentrations of finasteride by 16% and AUC by 31% when the two agents are coadministered. The interaction is of minor importance.
Finasteride; Tadalafil: (Moderate) Due to the potential for symptomatic hypotension, patients should be stable on alpha-blocker therapy before initiating therapy with the lowest recommended dose of tadalafil. Conversely, patients already receiving an optimized dose of tadalafil should be started on the lowest dose of the alpha-blocker; increases in the alpha-blocker dose should be done in stepwise fashion. When tadalafil is used for benign prostatic hypertrophy (BPH), discontinue alpha-blocker therapy at least 1 day prior to initiating tadalafil therapy. Other variables, such as intravascular volume depletion, concurrent antihypertensive therapy, or evidence of hemodynamic instability with alpha-blocker monotherapy, may affect the safety of concomitant use of tadalafil and an alpha-blocker. (Minor) Terazosin has been reported to increase peak concentrations of finasteride by 16% and AUC by 31% when the two agents are coadministered. The interaction is of minor importance.
General anesthetics: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Guaifenesin; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Haloperidol: (Moderate) In general, haloperidol should be used cautiously with antihypertensive agents due to the possibility of additive hypotension.
Hydralazine; Isosorbide Dinitrate, ISDN: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Ibuprofen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
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) The effects of iloprost on blood pressure may be additive to those of antihypertensive agents. Lower doses of the antihypertensive may be needed with combined treatment.
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 with antihypertensives such as alpha-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: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Isoproterenol: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Isosorbide Dinitrate, ISDN: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
Isosorbide Mononitrate: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
Ketamine: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Levonorgestrel; Ethinyl Estradiol: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Levonorgestrel; Ethinyl Estradiol; Ferrous Bisglycinate: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Levonorgestrel; Ethinyl Estradiol; Ferrous Fumarate: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Lidocaine; Epinephrine: (Moderate) Alpha-blockers antagonize the pressor effects of epinephrine. Do not use epinephrine to counteract hypotension caused by an alpha-blocker, as a reversal of the pressor effect of epinephrine may result in paradoxical further lowering of blood pressure.
Lofexidine: (Major) Because the central alpha-2 agonist effects of lofexidine can cause hypotension and orthostasis, the drug should be avoided, if possible, in combination with other medications that can significantly decrease blood pressure such as the antihypertensive alpha-blockers. If coadministration is required, blood pressure should be monitored, particularly after dose changes of either agent. Adjustments should be made as clinically indicated. 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.
Loratadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Lurasidone: (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.
Methohexital: (Moderate) Concurrent use of methohexital and alpha-blockers increases the risk of developing hypotension and hypothermia.
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. Methylphenidates can reduce the hypotensive effect of antihypertensive agents such as alpha-blockers.
Midodrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Milrinone: (Moderate) Concurrent administration of antihypertensive agents could lead to additive hypotension when administered with milrinone. Titrate milrinone dosage according to hemodynamic response.
Naproxen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Nesiritide, BNP: (Major) The potential for hypotension may be increased when coadministering nesiritide with antihypertensive agents.
Niacin, Niacinamide: (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: (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.
Nicotine: (Moderate) Nicotine use may reduce the clinical effects of the alpha-blockers. If significant changes in nicotine intake occur, the dosages of these drugs may need adjustment.
Nitrates: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
Nitroglycerin: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
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.
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.
Norepinephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly. Also, because norepinephrine is an alpha-adrenergic agonist, drugs with alpha-blocking activity such as alpha-blockers directly counteract the vasopressor effects of norepinephrine.
Norethindrone Acetate; Ethinyl Estradiol; Ferrous fumarate: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Norethindrone; Ethinyl Estradiol: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Norethindrone; Ethinyl Estradiol; Ferrous fumarate: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Norgestimate; Ethinyl Estradiol: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
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.
Oxymetazoline: (Major) Caution is advised when administering terazosin with oxymetazoline. Terazosin, an alpha adrenergic blocker, would likely antagonize the sympathomimetic effects of oxymetazoline, alpha adrenergic agonists; thereby reducing the effectiveness of oxymetazoline.
Paliperidone: (Moderate) Paliperidone may cause orthostatic hypotension, thereby enhancing the hypotensive effects of antihypertensive agents. Orthostatic vital signs should be monitored in patients receiving terazosin who are susceptible to hypotension.
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.
Phendimetrazine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
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 with antihypertensives such as alpha-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.
Phentermine: (Moderate) Monitor for desired antihypertensive effect of alpha-blockers when administered with phentermine, Sympathomimetics like phentermine can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Phentermine; Topiramate: (Moderate) Monitor for desired antihypertensive effect of alpha-blockers when administered with phentermine, Sympathomimetics like phentermine can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Prilocaine; Epinephrine: (Moderate) Alpha-blockers antagonize the pressor effects of epinephrine. Do not use epinephrine to counteract hypotension caused by an alpha-blocker, as a reversal of the pressor effect of epinephrine may result in paradoxical further lowering of blood pressure.
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.
Promethazine; Phenylephrine: (Major) Sympathomimetics can antagonize the effects of antihypertensives such as alpha-blockers when administered concomitantly.
Propofol: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Pseudoephedrine; Triprolidine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by alpha-blockers. Monitor blood pressure and heart rate.
Quinidine: (Moderate) Quinidine can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents due to the potential for additive hypotension.
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 with antihypertensives such as alpha-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.
Risperidone: (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.
Segesterone Acetate; Ethinyl Estradiol: (Minor) Estrogen-containing oral contraceptive may induce fluid retention and may increase blood pressure in some patients taking antihypertensive agents. Such patients should be monitored to confirm that the desired antihypertensive effect is being obtained.
Sevoflurane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
Sildenafil: (Moderate) Due to the potential for symptomatic hypotension, patients should be stable on alpha-blocker therapy before initiating therapy with the lowest dose of sildenafil. Conversely, patients already receiving an optimized dose of sildenafil should be started on the lowest dose of the alpha-blocker; increases in the alpha-blocker dose should be done in a stepwise fashion. Other variables, such as intravascular volume depletion, concurrent antihypertensive therapy, or evidence of hemodynamic instability with alpha-blocker monotherapy, may affect the safety of concomitant use of sildenafil and an alpha-blocker.
Silodosin: (Major) Silodosin should not be administered in combination with other alpha-blockers. The pharmacokinetic and pharmacodynamic interactions between silodosin and other alpha-blockers (used for high blood pressure or for benign prostatic hyperplasia) have not been determined. However, interactions or side effects (dizziness, hypotension, syncope, etc.) may be expected from the duplication of pharmacologic effects.
Tadalafil: (Moderate) Due to the potential for symptomatic hypotension, patients should be stable on alpha-blocker therapy before initiating therapy with the lowest recommended dose of tadalafil. Conversely, patients already receiving an optimized dose of tadalafil should be started on the lowest dose of the alpha-blocker; increases in the alpha-blocker dose should be done in stepwise fashion. When tadalafil is used for benign prostatic hypertrophy (BPH), discontinue alpha-blocker therapy at least 1 day prior to initiating tadalafil therapy. Other variables, such as intravascular volume depletion, concurrent antihypertensive therapy, or evidence of hemodynamic instability with alpha-blocker monotherapy, may affect the safety of concomitant use of tadalafil and an alpha-blocker.
Tamsulosin: (Major) Tamsulosin should not be administered in combination with other alpha-blockers. The pharmacokinetic and pharmacodynamic interactions between tamsulosin and other alpha-blockers (used for high blood pressure or for benign prostatic hyperplasia) have not been determined. However, interactions or side effects (dizziness, hypotension, syncope, etc.) may be expected from the duplication of pharmacologic effects.
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.
Thalidomide: (Moderate) Thalidomide and other agents that slow cardiac conduction such as alpha-blockers should be used cautiously due to the potential for additive bradycardia.
Thiothixene: (Moderate) Thiothixene should be used cautiously in patients receiving antihypertensive agents. Additive hypotensive effects are possible.
Tizanidine: (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.
Trandolapril; Verapamil: (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.
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.
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.
Vardenafil: (Moderate) Due to the potential for symptomatic hypotension, patients should be stable on alpha-blocker therapy before initiating therapy with the lowest dose of vardenafil. Conversely, patients already receiving an optimized dose of vardenafil should be started on the lowest dose of the alpha-blocker; increases in the alpha-blocker dose should be done in a stepwise fashion. Other variables, such as intravascular volume depletion, concurrent antihypertensive therapy, or evidence of hemodynamic instability with alpha-blocker monotherapy, may affect the safety of concomitant use of vardenafil and an alpha-blocker.
Verapamil: (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.
Ziprasidone: (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.

Hytrin/Terazosin/Terazosin Hydrochloride Oral Cap: 1mg, 2mg, 5mg, 10mg

20 mg/day PO.

20 mg/day PO.

Safety and efficacy have not been established.

Safety and efficacy have not been established.

Mechanism of Action: Terazosin causes peripheral vasodilation by selective, competitive inhibition of vascular postsynaptic alpha1-adrenergic receptors, thereby reducing peripheral vascular resistance and blood pressure. Unlike phenoxybenzamine and phentolamine, which are nonselective alpha-adrenergic blockers, terazosin does not interfere with the feedback mechanism for neurotransmitter release. Because it does not block presynaptic alpha2-receptors, terazosin does not cause reflex activation of norepinephrine release to produce reflex tachycardia. Also, tolerance to its antihypertensive effects does not occur.Terazosin reduces blood pressure in both the supine and standing positions, with more dramatic effects on diastolic blood pressure. These effects are similar to those of prazosin. There is no change in the patient's cardiac output or heart rate, and the response to exercise remains essentially the same.Terazosin also alters lipid metabolism, decreasing the levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, and very low-density lipoprotein (VLDL) cholesterol. Significant changes were not observed in triglycerides and high-density lipoprotein. The implications of these changes are not known. Terazosin also does not worsen and may improve LVH, does not worsen insulin resistance, and causes only mild sexual dysfunction.In the treatment of benign prostatic hypertrophy, terazosin blocks alpha1-adrenergic receptors present in the smooth muscle of the bladder neck and prostate, allowing the bladder neck and the prostate to relax. This causes less pressure on the urethra and increases urine flow. Terazosin appears to be more effective than finasteride (Proscar) for relieving symptoms associated with BPH.

Terazosin is administered orally.  The plasma half-life is about 12 hours. Terazosin is extensively bound to plasma proteins (90—94%) and is metabolized by the liver to one active and three inactive metabolites. Excretion of terazosin occurs as both unchanged drug and metabolites in the urine (40%) and in the feces (60%). Only 10% of the terazosin dose is excreted renally as unchanged drug.

Following oral administration, terazosin is almost completely absorbed, with minimal first-pass effect. Food may delay the time to peak concentrations by about 1 hour, but the presence of food has no significant effect on terazosin bioavailability. Antihypertensive effects are seen within 15 minutes, and peak plasma levels are observed approximately 1 hour after administration.

No adequate, well-controlled studies in pregnant women have been done to assess the safety of terazosin during pregnancy. Terazosin should be used during pregnancy only if the benefits to the mother outweigh the risks to the fetus. Terazosin is classified as FDA pregnancy category C.

Caution is advisable for breast-feeding mothers because it is not known whether terazosin distributes into breast milk. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.