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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 in children to relieve spasticity associated with conditions such as cerebral palsy and other disorders of the central nervous system.

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: Paediatric use (0-18 years): start ~0.3 mg/kg/day in 2-4 divided doses (preferably 4 divided doses)
Route: Oral
Frequency: 2-4 divided doses daily (preferably 4); raise cautiously at ~1 week intervals until sufficient for the child's individual requirements
Max: Max 40 mg/day in children <8 years; max 60 mg/day in children >8 years
Usual daily maintenance 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. Adult regimen for reference: titrate 5 mg tds x3 days, 10 mg tds x3 days, 15 mg tds x3 days, 20 mg tds x3 days; symptom control usually up to 60 mg daily, max >100 mg/day only in hospital under 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

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.

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 acting at spinal level to reduce excitatory neurotransmitter release and inhibit reflex muscle contraction.

Prescribing in practice

  • Never stop baclofen abruptly, as sudden withdrawal can precipitate a serious reaction including rebound spasticity, high fever, altered mental state and seizures — the dose must be tapered.
  • It causes sedation and muscle weakness, and the dose should be adjusted in renal impairment as it is largely renally excreted.
  • Introduce gradually and titrate to balance spasticity relief against drowsiness and hypotonia.

Monitoring

Monitor muscle tone, functional benefit, sedation and for any signs of withdrawal if doses are missed.

Counselling the patient

  • Do not stop this medicine suddenly — always reduce it gradually under medical advice.
  • It may cause drowsiness or muscle weakness, especially when starting.
  • Report increasing stiffness, fever or confusion if doses have been missed.

Evidence & guidelines

Baclofen is an established oral treatment for spasticity in children, and abrupt-withdrawal reactions are well documented.

Reference: NICE NG62 (Spasticity in under 19s); Royal College of Physicians Spasticity Guideline; 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).

Related

Curated clinical cross-links plus same-class fallbacks.

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