Indications: all forms of epilepsy except absence seizures; essential tremor.

Cautions: Same as phenobarbital.

Side Effects: Same as phenobarbital. also nausea and visual disturbances; less commonly vomiting, headache, and dizziness; rarely arthralgia.

Dose: epilepsy, ADULT and CHILD over 9 years, initially 125 mg daily at bedtime, increased by 125 mg every 3 days to 500 mg daily in 2 divided doses then increased according to response by 250 mg every 3 days to max. 1.5 g daily in 2 divided doses;

CHILD under 9 years, initially 125 mg daily at bedtime, increased by 125 mg every 3 days according to response; usual maintenance, CHILD under 2 years, 250–500 mg daily in 2 divided doses; 2–5 years, 500–750 mg daily in 2 divided doses; 6–9 years 0.75–1 g daily in 2 divided doses.

Essential tremor, initially 62.5 mg daily increased gradually over 2–3 weeks according to response; max. 750 mg daily.

Note: Monitor plasma concentrations of derived phenobarbital. Optimum range as for phenobarbital.