Adults 16 years and older: 1 g/day initial daily dose in two divided doses (500 mg twice daily) thereafter the daily dose may be increased in steps of 1 g every 2 to 4 weeks until effective antiepileptic control is achieved up to a maximum dose of 3 g daily.
Children: Less than 50 kg weight 20 mg/kg daily may be increased in steps of 20 mg/kg every weeks to a maximum of 60 mg/kg daily.
More than 50 kg weight may be given the adult dose (see previously).
As monotherapy: 500 mg daily increased after 2 weeks to 1 g daily. Further increases may be made in steps of 500 mg every 2 weeks up to maximum of 3 g daily.