Adult & childn 50 mg/kg in divided doses 6 hrly.
Meningitis or severe infections Up to 100 mg/kg/day.
Rickettsial diseases Continue 4 days after temp is normal.
Typhoid fever 8-10 days.
Full-term infant >2 wk 50 mg/kg daily in 4 divided doses.
Premature & full-term neonate 25 mg/kg daily.