Adult: Initial dose of 600 mg/day b.i.d, the dose should be increased by 300 mg/day every 3rd day to a dose of 1200 mg/day. Child 4-16 years: Initial dose of 8-10 mg/kg b.i.d. The target maintenance dose should be achieved over 2 wks & is dependent upon patient weight: 20-29 kg-900 mg/day, 29.1-39 kg-1200 mg/day, >39 kg-1800 mg/day.