Ethambutol and rifampicin serum levels in children: Second report on the combined administration of ethambutol and rifampicin

Abstract

Continuing our investigations on ethambutol serum levels in children, an oral dosage of 35 mg/kg body weight was given to the three age groups. Average serum concentrations reached 2 µg/ml ethambutol, as postulated by Pyle in the age groups 6 to <10 and 10 to 14 years. When ethambutol was given in combination with rifampicin (10 mg/kg) serum levels of ethambutol were higher than when it was given alone, so that even in the age group 2 to <6 years, average serum concentrations rose to a maximum of more than 2 µg/ml. Vice versa, rifampicin serum levels tended to be lower after combined administration than when rifampicin was given alone. Average rifampicin serum levels were almost the same in the three age groups under investigation.