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

The mechanism of action of methocarbamol is believed to be related to its central nervous system depressant activity. This effect may be mediated by inhibition of spinal polysynaptic reflexes, reduction of nerve transmission in spinal and supraspinal polysynaptic pathways, and prolongation of the refractory period of muscle cells. Methocarbamol has no direct effect on muscle fiber contraction, motor end plates, or peripheral nerve fibers.

Route of Administration: Oral

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.

Pediatric Use: Safety and effectiveness of Methocarbamol in pediatric patients below the age of 16 have not been established.

Methocarbamol may inhibit the effect of pyridostigmine bromide. Therefore, Methocarbamol should be used with caution in patients with myasthenia gravis receiving anticholinesterase agents.

Drug/Laboratory Test Interactions: Methocarbamol may cause color interference in certain screening tests for 5-hydroxyindoleacetic acid (5-HIAA) using nitrosonaphthol reagent and in screening tests for urinary vanillylmandelic acid (VMA) using the Gitlow method. Carcinogenesis, Mutagenesis, Impairment of Fertility: Long-term studies to evaluate the carcinogenic potential of Methocarbamol have not been performed. No studies have been conducted to assess its effect on mutagenesis or its potential to impair fertility.

Methocarbamol is contraindicated in patients hypersensitive to Methocarbamol or to any of the tablet components.

Adverse reactions reported with 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, vomiting
Hemic and lymphatic system: Leukopenia
Immune system: Hypersensitivity reactions
Nervous system: Amnesia, confusion, diplopia, dizziness, 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, urticaria

Pregnancy Category C. Animal reproduction studies have not been conducted with Methocarbamol. It is not known whether Methocarbamol can cause fetal harm or affect reproductive capacity. It should be used during pregnancy only if clearly needed. Methocarbamol and/or its metabolites are excreted in the milk of animals; it is not known whether it is excreted in human milk. Since many drugs are excreted in breast milk, caution should be exercised when administering to nursing mothers.

Patients should be warned that Methocarbamol may cause drowsiness or dizziness, which may impair the ability to drive or operate machinery due to its CNS depressant effect. Alcohol and other CNS depressants may enhance these effects.Safety in pregnancy has not been fully established, and fetal and congenital abnormalities have been reported following in utero exposure. Therefore, Methocarbamol should not be used in women who are or may become pregnant, especially in early pregnancy, unless clearly necessary.

Limited information is available on acute toxicity. Overdose is often associated with alcohol or other CNS depressants and may include nausea, drowsiness, blurred vision, hypotension, seizures, and coma. Deaths have been reported in overdose cases involving Methocarbamol alone or with other CNS depressants, alcohol, or psychotropic drugs.

Management is symptomatic and supportive, including airway maintenance, monitoring of vital signs and urine output, and intravenous fluids if required. The role of hemodialysis is unknown.

Centrally acting skeletal muscle relaxants

Protect from light. Store below 30°C. Keep out of reach of children.