Predictability of peak serum gentamicin concentration with dosage based on body surface area.

We examined gentamicin dosage based on body surface area (60 mg/m2 intravenously every eight hours) as a means of attaining therapeutic but nontoxic serum concentrations in 58 patients ranging in age from 0.7 to 73 years. All but one patient had peak serum levels between 3.4 and 8.0 microgram/ml. The mean serum gentamicin half-life was shorter in patients less than 10 years of age (76 minutes) than in patients aged 10 to 50 years (116 minutes) and in patients aged 50 to 63 years (184 minutes) (all significant at P less than 0.01). We conclude that gentamicin dosage based on body surface area produces uniform peak serum gentamicin concentrations in both children and adults, and that the safety and efficacy of a shorter dosage interval for children deserves investigation.