Centrally Acting Skeletal Muscle Relaxant Pregnancy: Should not be used during pregnancy — there is no experience with methocarbamol in human pregnancy and no animal data on effects on pregnancy, embryonic/fetal development, parturition or postnatal development; the potential risk to humans is not known. Should not be used during lactation (methocarbamol and/or its metabolites are excreted into milk in lactating dogs; excretion in human milk is unknown). No data are available on the effect on human fertility.

Methocarbamol

Brand names: Robaxin, Robaxisal

Methocarbamol is a centrally acting skeletal muscle relaxant used as an adjunct for the symptomatic relief of acute painful muscle spasm.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 1500 mg three times daily. At the beginning of treatment, 1500 mg four times a day is recommended

Route: Oral — film-coated tablets, taken with plenty of water

Frequency: Three times daily (four times daily at the start of treatment)

Max: In severe cases, patients may take up to 7500 mg of methocarbamol per day

Indication/duration: should be taken as long as the symptoms of muscle spasm persist, but not longer than 30 days. Paediatric population: the safety and efficacy of methocarbamol 1500 mg film-coated tablets in children and adolescents have not been established, and no paediatric dose is given in the SPC. Use with caution in patients with impaired renal function and/or impaired hepatic function (§4.4). Methocarbamol may cause colour interference in laboratory tests for hydroxyindoleacetic acid (5-HIAA) and vanillin mandelic acid (VMA). The tablets contain lactose (avoid in rare hereditary galactose intolerance, total lactase deficiency or glucose-galactose malabsorption) and are essentially sodium-free. CROSS-REFERENCE ONLY — the US label in the same bundle (Proficient Rx, 2020-08-01) is for 500 mg and 750 mg tablets and gives different figures: 500 mg tablets, adults, initial 3 tablets four times daily, maintenance 2 tablets four times daily; 750 mg tablets, adults, initial 2 tablets four times daily, maintenance 1 tablet every 4 hours or 2 tablets three times daily; 6 g/day for the first 48 to 72 hours (8 g/day for severe conditions), thereafter usually reduced to about 4 g/day. These are US figures for different tablet strengths and have not been verified against the UK SPC.

Dose adjustments

Renal

No numerical dose adjustment is given. SPC §4.4 states that methocarbamol should be used with caution in patients with impaired renal function and/or impaired hepatic function.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Comatose or precomatose states
Central nervous system (CNS) disorders
Myasthenia gravis
Patients with a tendency to epileptic convulsions

Side effects

Headache, dizziness and metallic taste (rare)
Nausea and vomiting (rare); diarrhoea
Agitation, anxiety and confusion (very rare)
Somnolence, coordination disorder, hypoesthesia and paraesthesia (frequency not known)
Bradycardia and hypotension (very rare)
Anaphylactic reaction, angioedema, rash, pruritus and urticaria
Syncope, nystagmus, tremor and seizure (very rare)

Interactions

Centrally acting medicinal products such as barbiturates, opioids and appetite suppressants — an increased interactive effect may occur
Alcohol — consumption during treatment may potentiate the effect of methocarbamol
Anticholinergics such as atropine, and other psychotropic medicinal products — their effect may be potentiated by methocarbamol
Pyridostigmine bromide — methocarbamol may attenuate its effect; methocarbamol must not be taken by patients with myasthenia gravis, especially those treated with pyridostigmine

Clinical monograph

How it works

Its muscle-relaxant effect is thought to result from central nervous system depression rather than a direct action on skeletal muscle.

Prescribing in practice

It can cause drowsiness and sedation, so warn patients about driving and operating machinery and take care when combined with other CNS depressants including alcohol.
Use with caution in elderly patients and those with hepatic impairment, and it is generally intended for short-term use.
Caution is advised in patients with a history of seizures or significant CNS disorders.

Monitoring

No routine laboratory monitoring is required, but review sedation, treatment response and the continued need for therapy.

Counselling the patient

This medicine may make you drowsy, so do not drive or operate machinery until you know how it affects you.
Avoid alcohol and other sedating medicines while taking it.
It is intended for short-term relief of muscle spasm.

Evidence & guidelines

Methocarbamol is a recognised short-term option for acute muscle spasm, with sedation being its principal limiting effect.

Reference: SPC Robaxin; Cochrane Review (Muscle relaxants for acute low back pain, 2003); NICE CG88 (Low Back Pain); Toth and Urtis, Am J Phys Med Rehabil 2004; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways