Muscle Relaxant — GABA-B Agonist Pregnancy: During pregnancy, especially the first three months, use only if of vital necessity; weigh maternal benefit against possible risk to the child. Baclofen crosses the placental barrier. In lactation, passes into breast milk in quantities so small no undesirable effects on the infant are expected.

Baclofen

Brand names: Lioresal

Baclofen is a skeletal-muscle relaxant used for chronic severe spasticity, such as in multiple sclerosis and spinal cord injury or disease.

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: Titrate: 5 mg three times a day for 3 days, then 10 mg three times a day for 3 days, then 15 mg three times a day for 3 days, then 20 mg three times a day for 3 days

Route: Oral

Frequency: Three times a day (titration schedule)

Max: Symptom control usually obtained up to 60 mg daily; max >100 mg/day not advised unless patient is in hospital under careful medical supervision

Adjust to individual patient requirements. Small frequent dosing may be better than larger spaced doses in some cases; some patients benefit from baclofen only at night for painful flexor spasm, or a single dose ~1 hour before specific tasks (washing, dressing, physiotherapy). Once maximum recommended dose reached, review whether to continue if no therapeutic effect within 6 weeks. Elderly: start with small doses titrated gradually against response under careful supervision. Patients with spastic states of cerebral origin: adopt a very cautious dosage schedule with appropriate surveillance.

Paediatric dose

Dose: 0.3 mg/kg

Route: Oral

Frequency: Starting dose ~0.3 mg/kg/day in 2-4 divided doses (preferably 4); raise cautiously at ~1 week intervals

Max: Max 40 mg/day in children <8 years; max 60 mg/day in children >8 years

Paediatric population 0-18 years. Usual maintenance daily dose ranges 0.75-2 mg/kg body weight. Baclofen tablets are not suitable for children below 33 kg body weight. Verify against a children's formulary.

Dose adjustments

Renal

In impaired renal function or chronic haemodialysis, select a particularly low dosage i.e. approx. 5 mg daily. Signs of overdose seen with >5 mg oral baclofen/day in renal impairment. Use with caution in end-stage renal failure (CKD stage 5).

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.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION The determination of optimal dosage requires individual titration. Start therapy at a low dosage and increase gradually until optimum effect is achieved (usually between 40-80 mg daily). The following dosage titration schedule is suggested: 5 mg t.i.d. for 3 days 10 mg t.i.d. for 3 days 15 mg t.i.d. for 3 days 20 mg t.i.d. for 3 days Thereafter additional increases may be necessary but the total daily dose should not exceed a maximum of 80 mg daily (20 mg q.i.d.). The lowest dose compatible with an optimal response is recommended. If benefits are not evident after a reasonable trial period, patients should be slowly withdrawn from the drug (See WARNINGS , Abrupt …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2026-01-21. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Hypersensitivity to baclofen or to any of the excipients
Peptic ulceration

Side effects

Somnolence, sedation (very common)
Nausea (very common)
Respiratory depression, confusional state, dizziness, hallucinations, depression (common)
Hypotension (common)
Muscular weakness, headache, ataxia, tremor, dry mouth (common)

Interactions

Use with extreme care in patients already receiving anti-hypertensive therapy (see SPC section 4.5)

Clinical monograph

How it works

It is a GABA-B receptor agonist that inhibits transmission of reflexes at the spinal level, reducing muscle tone and spasticity.

Prescribing in practice

Do not stop abruptly; withdrawal can cause seizures, hallucinations and rebound spasticity and can be life-threatening, especially with intrathecal use, so taper gradually.
Sedation, drowsiness and muscle hypotonia are common, and the dose should be reduced in renal impairment.
CNS and respiratory depression can occur in overdose; use with caution alongside other CNS depressants.

Monitoring

Review muscle tone and functional benefit against sedation and weakness, titrating gradually. Monitor more closely in renal impairment and ensure abrupt cessation is avoided.

Counselling the patient

Do not stop taking it suddenly; stopping abruptly can cause serious withdrawal effects.
It can make you drowsy; do not drive or operate machinery until you know how it affects you.
Avoid alcohol, which can add to the drowsiness.

Evidence & guidelines

Established treatment for spasticity (NICE NG220, multiple sclerosis management).

Reference: NICE NG109 (Spasticity in adults); UK Baclofen Pump Guidelines; 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.

Drugs

Baclofen · Muscle Relaxant — GABA-B Agonist

Pathways