Pharmacokinetics of single daily dose gentamicin in children with cancer

Purpose: To study the pharmacokinetics of single daily dose (SDD) gentamici n in children with cancer. Methods: Serum concentrations of gentamicin were prospectively measured at 0.5, 8, 16, and 24 hours after a single daily dose of gentamicin 6 mg/kg, g iven as a 30-minute infusion in 18 febrile children with cancer and a centr al venous catheter. Then the peak (0.5-hour) and 12-hour serum concentratio ns of gentamicin were prospectively measured after a SDD of 7 mg/kg during 73 febrile episodes in 54 pediatric cancer patients with suspected infectio ns. The aim was to achieve a peak serum concentration of 15 to 20 mu g/mL 1 0 times the minimum inhibitory concentration (MIC) for sensitive Pseudomona s strains, resulting in good bactericidal activity and a long post-antibiot ic effect (PAE) after a SDD of gentamicin. Results: The mean serum peak gentamicin concentration 30 minutes after the end of the infusion of 6 mg/kg was 13.3 +/- 4.0 mu g/mL. The mean serum con centration 16 hours after the infusion was 0.3 +/- 0.2 mu g/mL. The mean pe ak and 12-hour serum concentration after SDD of 7 mg/kg was 17.2 +/- 3.9 mu g/mL and 0.9 +/- 0.7 mu g/mL, respectively. The mean peak serum concentrat ion after SDD of 7 mg/kg in children younger than 5 years age (16.1 +/- 3.5 mu g/mL) was significantly lower than that of children over 5 years of age (18.2 +/- 3.9 mu g/mL; P = 0.02). The desired peak serum concentration was achieved in 67% of children younger and 84% of those older than 5 years of age. Conclusion: Adequate peak serum concentrations of gentamicin in children ma y be obtained with a SDD of 7 mg/kg. Children younger than 5 years of age a chieve lower peak serum gentamicin concentration after SDD of 7 mg/kg than those older than 5 years.