Indications: all forms of epilepsy.

Cautions: hepatic impairment; liver function must be monitored before and at 2-months intervals during first 6 months of therapy; monitor platelet function before major surgery; systemic lupus erythematosus; false-positive urine tests for ketones; avoid abrupt withdrawal; renal impairment; pregnancy; breast-feeding.

Contra-indications: active liver disease, family history of severe hepatic dysfunction; porphyria.

Side Effects: gastric irritation, nausea, hyperammonaemia; increased appetite and weight gain; transient hair loss with curly regrowth, less frequently increased alertness, aggression, hyperactivity, behavioural disturbances, ataxia, tremor, and vasculitis; rarely hepatic dysfunction (withdraw treatment immediately if persistent vomiting and abdominal pain, anorexia, jaundice, oedema, malaise, drowsiness, or loss of seizure control), lethargy, drowsiness, confusion, stupor, hallucinations, menstrual disturbances, anaemia, leucopenia, pancytopenia, hearing loss, and rash; very rarely pancreatitis, peripheral oedema, increase in bleeding time, extrapyramidal symptoms, dementia, encephalopathy, coma, gynaecomastia, Fanconi's syndrome, hirsutism, acne, enuresis, hyponatraemia, toxic epidermal necrolysis, and Stevens-Johnson syndrome.

Dose: By mouth, initially 600 mg daily in 2 divided doses, preferably after food, increased by 200 mg daily every 3 days to max. 2.5 g daily, usual maintenance dose 1–2 g daily (20–30 mg/kg daily); CHILD body-weight up to 20 kg, initially 20 mg/kg daily in divided doses, may be increased provided plasma concentration monitored (dose above 40 mg/kg daily also monitor clinical chemistry and haematological parameters); CHILD under 12 years body-weight over 20 kg, initially 400 mg daily in divided doses increased according to response (usual range 20–30 mg/kg daily); max. 35 mg/kg daily.