GABA-B Agonist Muscle Relaxant 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 centrally acting skeletal muscle relaxant used to relieve spasticity from neurological conditions and, in orthopaedic and rehabilitation settings, 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: 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

Skeletal muscle relaxant for spasticity. 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) to improve mobility. 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.

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

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 at spinal reflex pathways, reducing the excitability of motor neurones and decreasing muscle tone.

Prescribing in practice

Do not stop oral baclofen abruptly, as sudden withdrawal can precipitate a serious syndrome of rebound spasticity, hyperthermia, confusion and seizures; taper gradually.
Reduce the dose in renal impairment, as baclofen is largely renally excreted and accumulates, and use caution in the elderly and those with epilepsy.
Sedation and additive CNS depression occur with alcohol and other depressants.

Monitoring

Monitor muscle tone, sedation and CNS effects, and renal function in those at risk of accumulation, adjusting dose by clinical response.

Counselling the patient

Do not stop taking this suddenly; reductions should always be gradual and supervised.
It may cause drowsiness and dizziness, so take care with driving, alcohol and other sedating medicines.

Evidence & guidelines

Use of baclofen for spasticity is well established in clinical practice and supported by standard prescribing references.

Reference: NICE NG159 (Spasticity in Adults); SPC Lioresal; Cochrane Review (Baclofen for Spasticity); SIGN 113; 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