RESUMEN
PURPOSE: To study the pharmacokinetics of single daily dose (SDD) gentamicin 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, given as a 30-minute infusion in 18 febrile children with cancer and a central venous catheter. Then the peak (0.5-hour) and 12-hour serum concentrations of gentamicin were prospectively measured after a SDD of 7 mg/kg during 73 febrile episodes in 54 pediatric cancer patients with suspected infections. The aim was to achieve a peak serum concentration of 15 to 20 microg/mL 10 times the minimum inhibitory concentration (MIC) for sensitive Pseudomonas strains, resulting in good bactericidal activity and a long post-antibiotic 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 microg/mL. The mean serum concentration 16 hours after the infusion was 0.3 +/- 0.2 microg/mL. The mean peak and 12-hour serum concentration after SDD of 7 mg/kg was 17.2 +/- 3.9 microg/mL and 0.9 +/- 0.7 microg/mL, respectively. The mean peak serum concentration after SDD of 7 mg/kg in children younger than 5 years of age (16.1 +/- 3.5 microg/mL ) was significantly lower than that of children over 5 years of age (18.2 +/- 3.9 microg/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 may be obtained with a SDD of 7 mg/kg. Children younger than 5 years of age achieve lower peak serum gentamicin concentration after SDD of 7 mg/kg than those older than 5 years.