Robaxin

Muscle Relaxants, Centrally Acting, Plain

May be administered without regard to meals.

Nasogastric (NG) tube administration: Methocarbamol tablets may be crushed and suspended in water or saline solution to allow for NG administration.

Methocarbamol is administered intravenously or intramuscularly; do not administer subcutaneously.

Intravenous injection:
May be administered undiluted by direct IV injection at a maximum rate of 300 mg (3 mL of 10% injection) per minute.
Methocarbamol does not mix with any blood that may be aspirated into the syringe during administration; blood in the syringe can either be injected with the drug or the injection of methocarbamol can be stopped when the plunger reaches the blood.
Avoid extravasation of this hypertonic solution, which may result in thrombophlebitis.
The patient should be in a recumbent position during and for at least 10 to 15 minutes following the injection.
Switch to oral therapy as soon as feasible.
 
Intravenous infusion:
Dilute 1 vial (10 mL) with up to 250 mL of 0.9% Sodium Chloride injection or Dextrose 5% injection. Do NOT refrigerate diluted solution.
Maximum infusion rate is 300 mg/minute.
Avoid extravasation of this hypertonic solution, which may result in thrombophlebitis.
The patient should be in a recumbent position during and for at least 10 to 15 minutes following the injection.
Switch to oral therapy as soon as feasible.
 
Use in tetanus patients
Administration appears to have a beneficial effect in the control of the neuromuscular manifestations of tetanus, but does not replace tetanus antitoxin treatment or other usual supportive care for this condition.
For adults: Give initial doses intravenously directly into the tubing of the previously inserted indwelling needle; do not exceed maximal rates of administration. Once a nasogastric (NG) tube is placed, oral tablets (see NG administration) may then be given through the NG tube as directed.
For pediatric patients: Initial and maintenance dosages may be given by injection into tubing or by intravenous infusion with an appropriate quantity of fluid. See directions for intravenous use. Do not exceed maximal rates of administration.

Administer undiluted. Do not administer more than 500 mg (5 ml of 10% methocarbamol injection) into each gluteal region.

bradycardia / Rapid / Incidence not known
angioedema / Rapid / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known
seizures / Delayed / Incidence not known

hypotension / Rapid / Incidence not known
phlebitis / Rapid / Incidence not known
confusion / Early / Incidence not known
amnesia / Delayed / Incidence not known
jaundice / Delayed / Incidence not known
nystagmus / Delayed / Incidence not known
conjunctivitis / Delayed / Incidence not known
blurred vision / Early / Incidence not known
hemolysis / Early / Incidence not known
leukopenia / Delayed / Incidence not known

dyspepsia / Early / 1.0-10.0
nausea / Early / 1.0-10.0
metallic taste / Early / 1.0-10.0
dizziness / Early / 10.0
drowsiness / Early / 10.0
flushing / Rapid / Incidence not known
syncope / Early / Incidence not known
urticaria / Rapid / Incidence not known
pruritus / Rapid / Incidence not known
rash / Early / Incidence not known
injection site reaction / Rapid / Incidence not known
vertigo / Early / Incidence not known
headache / Early / Incidence not known
insomnia / Early / Incidence not known
vomiting / Early / Incidence not known
diplopia / Early / Incidence not known
fever / Early / Incidence not known
nasal congestion / Early / Incidence not known
urine discoloration / Early / Incidence not known

Robaxin

Rx

Oral and parenteral centrally acting muscle relaxant
Used as adjunct therapy for acute, painful musculoskeletal conditions and in the management of tetanus
Studies indicate the drug is not effective for spasticity

1,500 mg PO 4 times daily for 48 to 72 hours, initially, then reduce dose to 1,500 mg PO 3 times daily, 1,000 mg PO 4 times daily, or 750 mg PO every 4 hours. Up to 8 g/day may be used for severe conditions.

1,500 mg PO 4 times daily for 48 to 72 hours, initially, then reduce dose to 1,500 mg PO 3 times daily, 1,000 mg PO 4 times daily, or 750 mg PO every 4 hours. Up to 8 g/day may be used for severe conditions.

1 g IV or IM as a single dose may be adequate for moderate symptoms. May repeat dose every 8 hours up to 3 g/day for no more than 3 consecutive days for severe cases or in postoperative conditions in which oral administration is not feasible.

Initially, 1 to 2 grams IV directly into the tubing of inserted indwelling needle, administered at a rate of 300 mg/minute. An additional 1 to 2 grams IV infusion may be given, for a total initial dose of up to 3 gramsIV. Repeat dosage every 6 hours until a nasogastric (NG) tube can be inserted for oral therapy. The tablets or capsule contents may then be crushed and suspended in water or saline solutions and administered through the NG tube. Dosages of up to 24 grams/day NG/PO may be required.

Initially, 15 mg/kg (or 500 mg/m2) IV every 6 hours, if needed. Do NOT exceed total dose of 1.8 grams/m2/day IV for 3 consecutive days. May be given by IV injection into tubing (max rate undiluted: 3 mL/minute) or by IV infusion. Safety and effectiveness of methocarbamol injection in pediatric patients have not been established except in tetanus.

Specific guidelines for dosage adjustments in hepatic impairment are not available; cautious use is warranted based on reduced elimination in patients with cirrhosis.

Oral: Cautious use is warranted, particularly in patients with severe renal impairment or those patients on hemodialysis, as the clearance of methocarbamol is reduced.
Injectable: The use of methocarbamol injection is not recommended in patients with known or suspected renal pathology because of the polyethylene glycol 300 component of the injectable formulation, which is known to have increased pre-existing acidosis and urea retention in patients with renal impairment.

Acetaminophen; Caffeine; Dihydrocodeine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Acetaminophen; Codeine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Acetaminophen; Hydrocodone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Acetaminophen; Oxycodone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxycodone dosage by one-third to one-half when using the extended-release tablets.
Alfentanil: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a skeletal muscle relaxant, use a lower initial dose of the opiate and titrate to clinical response. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Alprazolam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Amobarbital: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Anxiolytics; Sedatives; and Hypnotics: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants. Dosage reduction of one or both agents may be necessary.
Apomorphine: (Moderate) Apomorphine causes significant somnolence. Concomitant administration of apomorphine and CNS depressants could result in additive depressant effects.
Aspirin, ASA; Butalbital; Caffeine: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Aspirin, ASA; Carisoprodol; Codeine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Aspirin, ASA; Oxycodone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxycodone dosage by one-third to one-half when using the extended-release tablets.
Atropine; Difenoxin: (Moderate) Concurrent administration of diphenoxylate/difenoxin with methocarbamol can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration.
Azelastine: (Moderate) Monitor for excessive sedation and somnolence during coadministration of azelastine and methocarbamol. Concurrent use may result in additive CNS depression.
Azelastine; Fluticasone: (Moderate) Monitor for excessive sedation and somnolence during coadministration of azelastine and methocarbamol. Concurrent use may result in additive CNS depression.
Baclofen: (Moderate) Monitor for excessive sedation and somnolence during coadministration of baclofen and methocarbamol. Concurrent use may result in additive CNS depression.
Barbiturates: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Belladonna; Opium: (Major) Concomitant use of opioid agonists with methocarbamol may cause respiratory depression, profound sedation, and death. Limit the use of opioid agonists with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Consider prescribing naloxone for emergency treatment of opioid overdose.
Benzhydrocodone; Acetaminophen: (Major) Concomitant use of methocarbamol with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Benzodiazepines: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Buprenorphine: (Major) Reserve concomitant prescribing of buprenorphine and methocarbamol for use in patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. Gradually tapering a patient off other CNS depressants or decreasing to the lowest effective dose is preferred in most cases of patients being treated for opioid use disorder. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death.
Buprenorphine; Naloxone: (Major) Reserve concomitant prescribing of buprenorphine and methocarbamol for use in patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. Gradually tapering a patient off other CNS depressants or decreasing to the lowest effective dose is preferred in most cases of patients being treated for opioid use disorder. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death.
Butabarbital: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Butalbital; Acetaminophen: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Butalbital; Acetaminophen; Caffeine: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Butalbital; Acetaminophen; Caffeine; Codeine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol. (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Butalbital; Aspirin; Caffeine; Codeine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol. (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Butorphanol: (Moderate) Concomitant use of butorphanol with other CNS depressants, such as methocarbamol, can potentiate the effects of butorphanol on respiratory depression, CNS depression, and sedation.
Cannabidiol: (Moderate) Monitor for excessive sedation and somnolence during coadministration of cannabidiol and methocarbamol. CNS depressants can potentiate the effects of cannabidiol.
Celecoxib; Tramadol: (Major) Concomitant use of tramadol with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Cenobamate: (Moderate) Monitor for excessive sedation and somnolence during coadministration of cenobamate and methocarbamol. Concurrent use may result in additive CNS depression.
Chlordiazepoxide: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Chlordiazepoxide; Amitriptyline: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Chlordiazepoxide; Clidinium: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Chlorpheniramine; Codeine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Chlorpheniramine; Hydrocodone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Chlorpromazine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Cholinesterase inhibitors: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Clonazepam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Clorazepate: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Clozapine: (Moderate) Skeletal muscle relaxants should be combined cautiously with clozapine because they could cause additive depressant effects and possible respiratory depression or hypotension.
Codeine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Codeine; Guaifenesin: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Codeine; Guaifenesin; Pseudoephedrine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Codeine; Phenylephrine; Promethazine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Codeine; Promethazine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Deutetrabenazine: (Moderate) Advise patients that concurrent use of deutetrabenazine and drugs that can cause CNS depression, such as methocarbamol, may have additive effects and worsen drowsiness or sedation.
Dexmedetomidine: (Moderate) Due to the anesthetic effects of dexmedetomidine, concurrent use with other CNS depressants, such as skeletal muscle relaxants, could result in additive sedative effects and possibly prolong recovery from anesthesia.
Diazepam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Difelikefalin: (Moderate) Monitor for dizziness, somnolence, mental status changes, and gait disturbances if concomitant use of difelikefalin with CNS depressants is necessary. Concomitant use may increase the risk for these adverse reactions.
Diphenoxylate; Atropine: (Moderate) Concurrent administration of diphenoxylate/difenoxin with methocarbamol can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration.
Donepezil: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Donepezil; Memantine: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Dronabinol: (Moderate) Concomitant use of dronabinol with other CNS depressants, such as methocarbamol, can potentiate the effects of dronabinol on respiratory depression.
Droperidol: (Major) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as droperidol. Combination therapy can cause additive effects of sedation and dizziness, which can impair the patient's ability to undertake tasks requiring mental alertness. Dosage adjustments of either or both medications may be necessary.
Esketamine: (Major) Closely monitor patients receiving esketamine and skeletal muscle relaxants for sedation and other CNS depressant effects. Patients who receive a dose of esketamine should not drive or engage in other activities requiring alertness until the next day after a restful sleep.
Estazolam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Ethanol: (Major) Advise patients to avoid alcohol consumption while taking CNS depressants. Alcohol consumption may result in additive CNS depression.
Fenfluramine: (Moderate) Monitor for excessive sedation and somnolence during coadministration of fenfluramine and methocarbamol. Concurrent use may result in additive CNS depression.
Fentanyl: (Major) Concomitant use of fentanyl with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Fluphenazine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Flurazepam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Food: (Major) Advise patients to avoid cannabis use while taking CNS depressants due to the risk for additive CNS depression and potential for other cognitive adverse reactions.
Gabapentin: (Major) Initiate gabapentin at the lowest recommended dose and monitor patients for symptoms of sedation and somnolence during coadministration of gabapentin and methocarbamol. Concomitant use of gabapentin with methocarbamol may cause additive CNS depression. Educate patients about the risks and symptoms of excessive CNS depression.
Galantamine: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Guaifenesin; Hydrocodone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Homatropine; Hydrocodone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Hydrocodone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Hydrocodone; Ibuprofen: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Hydrocodone; Pseudoephedrine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Hydromorphone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations.
Ibuprofen; Oxycodone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxycodone dosage by one-third to one-half when using the extended-release tablets.
Ketamine: (Moderate) The use of general anesthetics with other CNS depressants, including skeletal muscle relaxants, can potentiate CNS depression and/or increase the risk of developing respiratory depression.
Lasmiditan: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lasmiditan and methocarbamol. Concurrent use may result in additive CNS depression.
Lemborexant: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lemborexant and methocarbamol. Dosage adjustments of lemborexant and methocarbamol may be necessary when administered together because of potentially additive CNS effects. The risk of next-day impairment, including impaired driving, is increased if lemborexant is taken with other CNS depressants.
Levorphanol: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial levorphanol dosage by 50% or more.
Lofexidine: (Moderate) Monitor for additive hypotension, bradycardia, and sedation during coadministration of lofexidine and methocarbamol. Lofexidine can potentiate the effects of CNS depressants. Patients should be advised to avoid driving or performing any other tasks requiring mental alertness until the effects of the combination are known.
Lorazepam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Lumateperone: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lumateperone and methocarbamol. Concurrent use may result in additive CNS depression.
Meperidine: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations.
Methadone: (Major) Concomitant use of methadone with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Methohexital: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Methscopolamine: (Moderate) CNS depression can be increased when methscopolamine is combined with other CNS depressants such as skeletal muscle relaxants.
Metyrapone: (Moderate) Metyrapone may cause dizziness and/or drowsiness. Other drugs that may also cause drowsiness, such as methocarbamol, should be used with caution. Additive drowsiness and/or dizziness is possible.
Midazolam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Molindone: (Moderate) Molindone may cause central nervous system (CNS) depression thereby having additive effects with other drugs that can cause CNS depression such as methocarbamol. Caution is advisable during concurrent use.
Morphine: (Major) Concomitant use of morphine with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. For extended-release morphine tablets (MS Contin and Morphabond), start with 15 mg every 12 hours. Morphine; naltrexone should be initiated at 1/3 to 1/2 the recommended starting dosage. Educate patients about the risks and symptoms of respiratory depression and sedation.
Morphine; Naltrexone: (Major) Concomitant use of morphine with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. For extended-release morphine tablets (MS Contin and Morphabond), start with 15 mg every 12 hours. Morphine; naltrexone should be initiated at 1/3 to 1/2 the recommended starting dosage. Educate patients about the risks and symptoms of respiratory depression and sedation.
Nabilone: (Moderate) Concomitant use of nabilone with other CNS depressants like methocarbamol can potentiate the effects of nabilone on respiratory depression.
Nalbuphine: (Major) Concomitant use of nalbuphine with methocarbamol may cause excessive sedation and somnolence. Limit the use of nalbuphine with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations.
Neostigmine: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Neostigmine; Glycopyrrolate: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Oliceridine: (Major) Concomitant use of oliceridine with methocarbamol may cause excessive sedation and somnolence. Limit the use of oliceridine with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Oxazepam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Oxycodone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxycodone dosage by one-third to one-half when using the extended-release tablets.
Oxymorphone: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxymorphone dosage by one-third to one-half.
Pentazocine: (Major) Concomitant use of pentazocine with methocarbamol may cause respiratory depression, profound sedation, and death. Limit the use of pentazocine with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Consider prescribing naloxone for the emergency treatment of opioid overdose.
Pentazocine; Naloxone: (Major) Concomitant use of pentazocine with methocarbamol may cause respiratory depression, profound sedation, and death. Limit the use of pentazocine with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Consider prescribing naloxone for the emergency treatment of opioid overdose.
Pentobarbital: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Perampanel: (Moderate) Co-administration of perampanel with CNS depressants, including ethanol, may increase CNS depression. The combination of perampanel (particularly at high doses) with ethanol has led to decreased mental alertness and ability to perform complex tasks (such as driving), as well as increased levels of anger, confusion, and depression; similar reactions should be expected with concomitant use of other CNS depressants, such as methocarbamol.
Perphenazine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Perphenazine; Amitriptyline: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Phenobarbital: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Phenothiazines: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Physostigmine: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Pregabalin: (Major) Initiate pregabalin at the lowest recommended dose and monitor patients for symptoms of sedation and somnolence during coadministration of pregabalin and methocarbamol. Concomitant use of pregabalin with methocarbamol may cause additive CNS depression. Educate patients about the risks and symptoms of excessive CNS depression.
Primidone: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Prochlorperazine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Promethazine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Promethazine; Dextromethorphan: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Promethazine; Phenylephrine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Pyridostigmine: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Quazepam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Remifentanil: (Major) Concomitant use of remifentanil with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Remimazolam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Rivastigmine: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Secobarbital: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as barbiturates. Dosage reduction of one or both agents may be necessary.
Sedating H1-blockers: (Moderate) Methocarbamol may cause additive CNS depression if used concomitantly with other CNS depressants such as sedating H1-blockers. Combination therapy can cause additive effects of sedation and dizziness, which can impair the patient's ability to undertake tasks requiring mental alertness. Dosage adjustments of either or both medications may be necessary.
Stiripentol: (Moderate) Monitor for excessive sedation and somnolence during coadministration of stiripentol and methocarbamol. CNS depressants can potentiate the effects of stiripentol.
Sufentanil: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a skeletal muscle relaxant, use a lower initial dose of the opiate and titrate to clinical response. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Tacrine: (Moderate) Methocarbamol may inhibit the effect of cholinesterase inhibitors. Methocarbamol also has sedative properties that may interfere with cognition. Therefore, methocarbamol should be used with caution in patients receiving cholinesterase inhibitors.
Tapentadol: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations.
Temazepam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Thalidomide: (Moderate) Thalidomide frequently causes drowsiness and somnolence and may enhance the sedative activity of methocarbamol.
Thioridazine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Tramadol: (Major) Concomitant use of tramadol with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Tramadol; Acetaminophen: (Major) Concomitant use of tramadol with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Triazolam: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given.
Tricyclic antidepressants: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and tricyclic antidepressants due to the risk for additive CNS depression.
Trifluoperazine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and phenothiazines due to the risk for additive CNS depression; dosage adjustments may be necessary.
Ziconotide: (Moderate) Due to potentially additive effects, dosage adjustments may be necessary if ziconotide is used with a drug that has CNS depressant effects such as methocarbamol. Coadministration of CNS depressants may increase drowsiness, dizziness, and confusion that are associated with ziconotide.
Ziprasidone: (Moderate) Ziprasidone has the potential to impair cognitive and motor skills. Additive CNS depressant effects are possible when ziprasidone is used concurrently with any CNS depressant, including methocarbamol.

Methocarbamol/Robaxin Intramuscular Inj Sol: 1mL, 100mg
Methocarbamol/Robaxin Intravenous Inj Sol: 1mL, 100mg
Methocarbamol/Robaxin Oral Tab: 500mg, 750mg, 1000mg

24 grams/day PO or 12 grams/day IV for tetanus; 8 grams/day PO or 3 grams/day IM/IV for acute muscle spasm and 4.5 grams/day PO in chronic use.

24 grams/day PO or 12 grams/day IV for tetanus; 8 grams/day PO or 3 grams/day IM/IV for acute muscle spasm and 4.5 grams/day PO in chronic use.

16 years and older: 8 grams/day PO or 3 grams/day IM/IV for acute muscle spasm (first 48 to 72 hours) and 4.5 grams/day PO in chronic use; 1.8 grams/m2/day IV for tetanus.
Less than 16 years: 1.8 grams/m2/day IV for tetanus; safety and efficacy have not been established for other indications.

1.8 grams/m2/day IV for tetanus; safety and efficacy have not been established for other indications.

Safety and efficacy have not been established.

The exact mechanism of action of methocarbamol is unknown. Unlike neuromuscular blockers, methocarbamol does not have an effect on neuronal conduction, neuromuscular transmission, or muscle excitability. Similar to carisoprodol, chlorzoxazone, and cyclobenzaprine, methocarbamol has no direct effect on skeletal muscle. Its skeletal muscle relaxant effects are probably due to its central nervous system depressant effects. CNS depression leads to sedation and a reduction in skeletal muscle spasms. These effects are accompanied by relief of pain and an increase in the mobility of the affected muscles. Pain relief is postulated to be due to alterations in the perception of pain.

Methocarbamol is administered intramuscularly, intravenously, or orally. Once in the systemic circulation, methocarbamol is widely distributed throughout the body. In animal studies, the highest concentrations were attained in the kidney and liver; distribution across the placenta was also observed. It is not known if methocarbamol is excreted in human breast milk. Methocarbamol is extensively metabolized by dealkylation and hydroxylation; conjugation is also likely. Essentially all methocarbamol metabolites are eliminated in the urine. Small amounts of unchanged methocarbamol also are excreted in the urine. The mean plasma elimination half-life is about 1 to 2 hours.

After oral administration, methocarbamol is rapidly and completely absorbed from the gastrointestinal tract. Peak blood or serum concentrations occur in approximately 1 to 2 hours. The onset of action is usually within 30 minutes after oral administration.

After IV administration of methocarbamol the onset of action is almost immediate.

Absorption after IM administration of methocarbamol is not known.

Because pregnancy outcome data are too limited to be conclusive, methocarbamol should not be used in females who are pregnant or may become pregnant and particularly during early pregnancy unless the benefits to the mother outweigh the possible fetal and maternal risks. Safe and effective use during pregnancy or with respect to fetal development has not been established. There have been reports of human fetal and congenital abnormalities following in utero exposure to methocarbamol. In one case, an infant was born with multiple joint contractures after in utero exposure to methocarbamol and propoxyphene for 3 days during the first trimester of pregnancy. In the Collaborative Perinatal Project, 6 infants with inguinal hernia were observed from a total of 119 in utero exposures to methocarbamol at any time during the pregnancies; however, a causal association between the drug and the defect was not established. The effects of methocarbamol during labor and delivery or with regard to fertility or reproduction capacity are unknown.

Methocarbamol should be used with caution during breast-feeding. Methocarbamol and/or its metabolites are excreted in the milk of dogs; however, it is not known if methocarbamol or its metabolites are excreted in human milk.