Vancomycin dosing in obese pediatric patients.

Background: Data are lacking to guide antimicrobial dosing for overweight children. The authors hypothesized that obese children would have increased vancomycin serum trough concentrations compared with nonobese children. Methods: A matched study design was employed to compare retrospectively vancomycin trough concentrations. Results: Among 24 matched pairs, obese patients received 14.1 +/- 1.5 mg per kilogram and nonobese children 14.9 +/- 0.9 mg per kilogram of vancomycin per kilogram of vancomycin (P = .03). There was a trend toward higher vancomycin serum concentrations in obese (6.9 +/- 4.30 mu g/mL) versus nonobese children (4.8 +/- 3.08 mu g/mL; P = .052). Mean half-life in obese patients was 2.9 +/- 0.29 hours and volume of distribution was 0.35 +/- 0.15 L/kg. Conclusions: Since obesity did not alter vancomycin trough concentrations, overweight children should receive vancomycin based on actual body weight. However, since vancomycin troughs were substantially lower than those recommended for adults, further studies of vancomycin metabolism in children are needed.