Methocarbamol

Indications and Usage Section INDICATIONS AND USAGE Methocarbamol is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions. The mode of action of methocarbamol has not been clearly identified, but may be related to its sedative properties. Methocarbamol does not directly relax tense skeletal muscles in man.

Dosage and Administration Section DOSAGE AND ADMINISTRATION Methocarbamol, 500 mg — Adults: Initial dosage: 3 tablets q.i.d. Maintenance dosage: 2 tablets q.i.d. Methocarbamol, 750 mg — Adults: Initial dosage: 2 tablets q.i.d. Maintenance dosage: 1 tablet q.4h. or 2 tablets t.i.d. Six grams a day are recommended for the first 48 to 72 hours of treatment. (For severe conditions 8 grams a day may be administered). Thereafter, the dosage can usually be reduced to approximately 4 grams a day.

CONTRAINDICATIONS Methocarbamol tablets, USP are contraindicated in patients hypersensitive to methocarbamol or to any of the tablet components.

ADVERSE REACTIONS Adverse reactions reported coincident with the administration of methocarbamol include: Body as a whole : Anaphylactic reaction, angioneurotic edema, fever, headache Cardiovascular system : Bradycardia, flushing, hypotension, syncope, thrombophlebitis Digestive system: Dyspepsia, jaundice (including cholestatic jaundice), nausea and vomiting Hemic and lymphatic system: Leukopenia Immune system : Hypersensitivity reactions Nervous system: Amnesia, confusion, diplopia, dizziness or lightheadedness, drowsiness, insomnia, mild muscular incoordination, nystagmus, sedation, seizures (including grand mal), vertigo Skin and special senses : Blurred vision, conjunctivitis, nasal congestion, metallic taste, pruritus, rash, urticarial To report SUSPECTED ADVERSE REACTIONS contact AvKARE at 1-855-361-3993; email drugsafety@avkare.com; or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Drug Interactions See Error! Hyperlink reference not valid. and PRECAUTIONS for interaction with CNS drugs and alcohol. Methocarbamol may inhibit the effect of pyridostigmine bromide. Therefore, methocarbamol should be used with caution in patients with myasthenia gravis receiving anticholinesterase agents.

Special populations Elderly The mean (± SD) elimination half-life of methocarbamol in elderly healthy volunteers (mean [± SD] age, 69 [± 4] years) was slightly prolonged compared to a younger (mean [± SD] age, 53.3 [± 8.8] years), healthy population (1.5 [±0.4] hours versus 1.1 [± 0.27] hours, respectively). The fraction of bound methocarbamol was slightly decreased in the elderly versus younger volunteers (41 to 43% versus 46 to 50%, respectively). Renally impaired The clearance of methocarbamol in 8 renally-impaired patients on maintenance hemodialysis was reduced about 40% compared to 17 normal subjects, although the mean (± SD) elimination half-life in these two groups was similar: 1.2 (± 0.6) versus 1.1 (± 0.3) hours, respectively. Hepatically impaired In 8 patients with cirrhosis secondary to alcohol abuse, the mean total clearance of methocarbamol was reduced approximately 70% compared to that obtained in 8 age- and weight-matched normal subjects. The mean (± SD) elimination half-life in the cirrhotic patients and the normal subjects was 3.38 (±1.62) hours and 1.11 (± 0.27) hours, respectively. The percent of methocarbamol bound to plasma proteins was decreased to approximately 40 to 45% compared to 46 to 50% in the normal subjects.

DESCRIPTION Methocarbamol Tablets, USP, 500 mg, a carbamate derivative of guaifenesin, is a central nervous system (CNS) depressant with sedative and musculoskeletal relaxant properties. The chemical name of methocarbamol is 3-(2-methoxyphenoxy)-1, 2-propanediol 1-carbamate and has the empirical formula C 11 H 15 NO 5 . Its molecular weight is 241.24. The structural formula is shown below. Methocarbamol is a white powder, sparingly soluble in water and chloroform, soluble in alcohol (only with heating) and propylene glycol, and insoluble in benzene and n -hexane. Each tablet, for oral administration, contains either 500 mg of methocarbamol, USP. The inactive ingredients present are colloidal silicon dioxide, magnesium stearate, povidone, pregelatinized corn starch, purified water, sodium starch glycolate, and stearic acid. The chemical name of methocarbamol is 3-(2-methoxyphenoxy)-1, 2-propanediol 1-carbamate and has the empirical formula C11H15NO5. Its molecular weight is 241.24. The structural formula is shown below.

Overdosage Limited information is available on the acute toxicity of methocarbamol. Overdose of methocarbamol is frequently in conjunction with alcohol or other CNS depressants and includes the following symptoms: nausea, drowsiness, blurred vision, hypotension, seizures, and coma. In post-marketing experience, deaths have been reported with an overdose of methocarbamol alone or in the presence of other CNS depressants, alcohol or psychotropic drugs. Treatment Management of overdose includes symptomatic and supportive treatment. Supportive measures include maintenance of an adequate airway, monitoring urinary output and vital signs, and administration of intravenous fluids if necessary. The usefulness of hemodialysis in managing overdose is unknown.

HOW SUPPLIED Methocarbamol Tablets, USP 500 mg — white, round, convex face, debossed “611” over bisect and “O” below bisect on one side and plain on the reverse side. Available in: Bottles of 30, NDC 85534-0057-0 (repackaged from NDC 69584-611-XX) Bottles of 60, NDC 85534-0057-1 (repackaged from NDC 69584-611-XX) Bottles of 90, NDC 85534-0057-2 (repackaged from NDC 69584-611-XX) Bottles of 120, NDC 85534-0057-3 (repackaged from NDC 69584-611-XX) Methocarbamol Tablets, USP 750 mg — white, capsule shape, convex face, debossed “612” on one side and debossed “O” on the reverse side. Available in: Bottles of 30, NDC 85534-0022-0 (repackaged from NDC 69584-612-XX) Bottles of 60, NDC 85534-0022-1 (repackaged from NDC 69584-612-XX) Bottles of 90, NDC 85534-0022-2 (repackaged from NDC 69584-612-XX) Bottles of 120, NDC 85534-0022-3 (repackaged from NDC 69584-612-XX) Store at 20°– 25°C (68°– 77°F) [See USP Controlled Room Temperature]. Dispense in tight container. For more information, call Oxford Pharmaceuticals, LLC at 1-844-508‐1455, 8:00 AM to 4.30 PM ET, Monday – Friday Distributed by: Hawaii Repack, Inc. 677 Ala Moana Blvd Ste 700, Honolulu, Hawaii-96813