Adult & childn >12 yr 1-2 g once daily or in 2 divided doses. Max: 4 g/day. Uncomplicated gonorrhoea 250 mg IM as a single dose. Surgical prophylaxis 1 g IV as a single dose 1-2 hr before surgery. ChildnSkin infections 50-75 mg/kg once daily or in 2 divided doses. Max: 2 g/day. Meningitis 100 mg/kg/day in divided doses 12 hrly, max: 4 g/day.