This is a skeletal muscle relaxant.

Indications: chronic severe spasticity resulting from disorders such as multiple sclerosis or traumatic partial section of spinal cord.

Cautions: psychiatric illness, Parkinson's disease, cerebrovascular disease, elderly; respiratory impairment; epilepsy; history of peptic ulcer (avoid oral route in active peptic ulceration); diabetes; hypertonic bladder sphincter; avoid abrupt withdrawal (risk of hyperactive state, may exacerbate spasticity, and precipitate autonomic dysfunction including hyperthermia, psychiatric reactions and convulsions)

Contra-indications: Specific contra-indications for intrathecal treatment local or systemic infection.

Renal impairment: risk of toxicity—use smaller doses (e.g. 5 mg daily by mouth) and if necessary increase dosage interval; if eGFR less than 15 ml/minute/1.73m2 manufacturer advises use by mouth only if potential benefit outweighs risk; excreted by kidney.

Pregnancy: manufacturer advises use only if potential benefit outweighs risk (toxicity in animal studies)

Breast-feeding: present in milk—amount probably too small to be harmful

Side Effects: gastro-intestinal disturbances, dry mouth; hypotension, respiratory or cardiovascular depression; sedation, drowsiness, confusion, dizziness, ataxia, hallucinations, nightmares, headache, euphoria, insomnia, depression, anxiety, agitation, tremor; seizure; urinary disturbances; myalgia; visual disorders; rash, hyperhidrosis; rarely taste disturbances, abdominal pain, changes in hepatic function, paraesthesia, erectile dysfunction, dysarthria; very rarely hypothermia.

Dose: By mouth, ADULT over 18 years, initially 5 mg 3 times daily, gradually increased; usual maintenance dose up to 60 mg daily in divided doses (max. 100 mg daily); CHILD under 18 years, initially 300 micrograms/kg daily in 4 divided doses, increased gradually at weekly intervals until satisfactory response; usual maintenance dose 0.75–2 mg/kg daily in divided doses; CHILD up to 8 years, max. total daily dose 40 mg/day; CHILD 8–18 years, max. total daily dose 60 mg/day.

Note : Review treatment if no benefit within 6 weeks of achieving max. dose By intrathecal injection, specialist use only, severe chronic spasticity unresponsive to oral antispastic drugs (or where side effects; of oral therapy unacceptable) or as alternative to ablative neurosurgical procedures, ADULT over 18 years, initial test dose 25–50 micrograms over at least 1 minute via catheter or lumbar puncture, increased in 25-microgram steps (not more often than every 24 hours) to max. 100 micrograms to determine appropriate dose, then dose-titration phase, most often using infusion pump (implanted into chest wall or abdominal wall tissues) to establish maintenance dose (ranging from 12 micrograms to 2 mg daily for spasticity of spinal origin or 22 micrograms to 1.4 mg daily for spasticity of cerebral origin) retaining some spasticity to avoid sensation of paralysis; CHILD 4–18 years (spasticity of cerebral or spinal origin only), initial test dose 25–50 micrograms then titrated as for ADULT, initial maintenance dose 25– 200 micrograms daily, adjusted according to response.