Methocarbamol

Oral
Painful muscle spasm associated with acute musculoskeletal conditions
Adult: As an adjunct, for short-term symptomatic treatment: Initially, 1,500 mg 4 times daily for 2-3 days (may give up to 8,000 mg daily in severe conditions). Usual maintenance dose: 2,250-4,500 mg daily in 3-4 divided doses. Dosing recommendations may vary among individual products and between countries (refer to specific product guidelines).
Elderly: Dose reduction may be required.

Parenteral
Painful muscle spasm associated with acute musculoskeletal conditions
Adult: As an adjunct, for short-term symptomatic treatment: Dose is based on the severity of the condition and therapeutic response. Initially: 1,000 mg as a single dose. In severe cases or when oral therapy is not feasible: May give additional 1,000 mg 8 hourly; Max of 3,000 mg daily for no more than 3 consecutive days. If condition persists, may repeat course of treatment after a drug-free interval of 48 hours. Doses may be given via slow IV inj (Max rate of 300 mg/minute), IV infusion; or deep IM inj (Max of 500 mg/gluteal region). Dosing recommendations may vary among individual products and between countries (refer to specific product guidelines).
Renal impairment: Contraindicated.
Reconstitution: IV infusion: Dilute with appropriate amount of NaCl 0.9% inj or 5% dextrose inj to prepare the desired concentration. Refer to specific product guidelines.

Intravenous
Tetanus
Adult: As an adjunct, for management: Initially, 1,000-2,000 mg via direct IV inj. May give additional 1,000-2,000 mg via IV infusion, to give a total initial dose of up to 3,000 mg. Repeat dosage 6 hourly until nasogastric tube can be inserted. Treatment guidelines may vary among individual products and between countries (refer to specific product guidelines).
Child: As an adjunct, for management: Initially, 15 mg/kg or 500 mg/m²; may repeat 6 hourly if needed. Max total: 1,800 mg/m² for 3 consecutive days. Treatment guidelines may vary among individual products and between countries (refer to specific product guidelines).
Renal impairment: Contraindicated.
Reconstitution: IV infusion: Dilute with appropriate amount of NaCl 0.9% inj or 5% dextrose inj to prepare the desired concentration. Refer to specific product guidelines.

May be taken with or without food. May be taken w/ meals to reduce GI discomfort.

Brain damage; epilepsy; myasthenia gravis, coma or pre-coma states. Renal impairment (inj).

Patient must be in a recumbent position during and for at least 10-15 minutes after administration (IV). Renal (oral) and hepatic impairment. Children (when used in tetanus) and elderly. Pregnancy and lactation. Patient Counselling This drug may cause dizziness or drowsiness, if affected, do not drive or operate machinery. Monitoring Parameters Monitor for signs of bradycardia, hypotension; extravasation (IV).

Significant: CNS depression. Blood and lymphatic system disorders: Leucopenia. Cardiac disorders: Bradycardia. Ear and labyrinth disorders: Vertigo. Eye disorders: Blurred vision, nystagmus, diplopia, conjunctivitis. Gastrointestinal disorders: Dyspepsia, nausea, vomiting, metallic taste. General disorders and administration site conditions: Fever; inj site pain and sloughing (IV/IM). Hepatobiliary disorders: Jaundice (including cholestatic jaundice). Immune system disorders: Hypersensitivity reactions (e.g. anaphylaxis, angioedema). Nervous system disorders: Headache, seizures, mild muscular incoordination, dizziness, drowsiness. Psychiatric disorders: Confusion, amnesia, insomnia. Respiratory, thoracic and mediastinal disorders: Nasal congestion. Skin and subcutaneous tissue disorders: Pruritus, rash, urticaria. Vascular disorders: Flushing, hypotension, syncope, thrombophlebitis.

Symptoms: Nausea, drowsiness, blurred vision, hypotension, seizures, coma. Management: Symptomatic and supportive treatment. Maintain adequate airway, monitor vital signs and urine output, administer IV fluids if needed.

May potentiate the effects of other CNS depressants and stimulants (e.g. barbiturates, anaesthetics, appetite suppressants), anticholinergics (e.g. atropine) and certain psychotropic drugs. May suppress the effect of pyridostigmine bromide.

May enhance the CNS depressant effect of alcohol.

May produce a colour 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.

Methocarbamol is a carbamate derivative of guaifenesin that relaxes skeletal muscle by general CNS depression.
Onset: Approx 30 minutes (oral).
Absorption: Rapidly and almost completely absorbed from the gastrointestinal tract. Time to peak plasma concentration: 1-2 hours (oral).
Distribution: Plasma protein binding: 46-50%.
Metabolism: Metabolised in the liver via dealkylation and hydroxylation.
Excretion: Via urine (mainly as metabolites). Elimination half-life: 1-2 hours.

Intravenous: Intact vial: Store between 15-30°C. Oral: Tab: Store between 20-25°C. Parenteral: Intact vial: Store between 15-30°C.

Muscle Relaxants

M03BA03 - methocarbamol ; Belongs to the class of carbamic esters. Used as centrally-acting muscle relaxants.