Baclofen

GABA-B Agonist·Musculoskeletal & Rheumatology

Severe muscle spasticity associated with MS, spinal cord injury, cerebral palsy, stroke

Authority requiredPBSSPASMOLYTICLioresal, Clofen10 mg tablet+2

Max Dose

100 mg/day

Half-life

3-4 h

Withdrawal

SEIZURE RISK

Renal Adj.

MANDATORY

Rapid Summary

Overview

Central muscle relaxant. Highly effective for spasticity originating from spinal cord or brain injury. Acts as a potent depressant on spinal reflexes.

Maximum Dose

Max 100 mg/day (Requires very slow titration to prevent profound sedation/weakness).

Clinical Focus

Abrupt cessation causes severe, life-threatening withdrawal (seizures, hallucinations, hyperthermia). Must be tapered over weeks.

Bottom Line

Baclofen is the first-line skeletal muscle relaxant for spasticity (MS, spinal cord injury), but causes significant sedation and abrupt withdrawal can cause life-threatening seizures and autonomic instability.

Formulation & Access

Brand Names

Lioresal, Clofen

Oral Routes

Tablets (10 mg, 25 mg). Oral liquid (5 mg/mL).

Parenteral

Ampoules for Intrathecal injection/infusion ONLY. Never IV.

Prescribing & PBS

Authority Required (PBS) for specific neurological indications.

Indications & Use

Primary

PBSTGA

Severe muscle spasticity associated with MS, spinal cord injury, cerebral palsy, stroke.

Off-Label

OFF

Hiccups, severe alcohol cravings (high dose).

Clinical Place

The gold-standard oral anti-spasmodic for upper motor neuron lesions.

Quick reference

Class & Role

GABA-B Agonist — Central muscle relaxant.

Route / Formulation

Tablets (10 mg, 25 mg). Oral liquid (5 mg/mL). (Lioresal, Clofen)

Usual Dose & Max

Start PO 5 mg TDS. Titrate up by 15 mg/day every 3 days. Maintenance usually 30-75 mg/day. Max 100 mg/day.

Key Indication Doses

Chronic Spasticity: Start PO 5 mg TDS. Titrate up by 15 mg/day every 3 days. Maintenance usually 30-75 mg/day. Max 100 mg/day. Intrathecal (Severe): Continuous infusion directly into the spinal fluid via an implanted pump (Specialist only). Renal Impairment: Reduce dose to 5 mg/day if eGFR < 30. High risk of severe encephalopathy and coma.

Best Uses

Avoid / Cautions

Active peptic ulceration, severe psychosis/schizophrenia (can exacerbate). Pregnancy Category B3.

Key Risks

Neurological: Seizures, acute psychosis, and hallucinations upon abrupt withdrawal. HIGH — Profound sedation, dizziness, severe hypotonia (muscle weakness making the patient unable to stand). Cardiovascular: Hypotension. Gastrointestinal: Nausea (usually transient).

Key Interactions

Extreme additive CNS depression and weakness if combined with Opioids, Benzodiazepines, or Alcohol. Antihypertensives (Additive hypotension).

Monitoring

Baseline and routine U&E and eGFR. Assess muscle tone. Over-treating spasticity will remove the 'stiffness' the patient relies on to stand up and walk, rendering them bedbound.

Clinical Pearl

If an implanted intrathecal baclofen pump runs dry or the catheter snaps, the patient will be plunged into massive, fatal withdrawal within hours. This is a medical emergency requiring massive doses of oral baclofen or ICU sedation with diazepam/propofol until the pump is fixed.

Access

Authority requiredLioresal, Clofen10 mg tablet

Brand: Lioresal, Clofen
PBS status: Authority required
Formulation: Tablets (10 mg, 25 mg)