Adult & childn 50 mg/kg in divided doses every 6 hr, up to 100 mg/kg in severe infections due to moderately resistant organisms. Duration of treatment:
Rickettsial diseases Continue for 4 days after temp is normal;
typhoid fever 8-10 days.
Full-term infant >2 wk Up to 50 mg/kg daily in 4 divided doses.
Premature & full-term neonate 25 mg/kg daily.