Pharmacokinetics of single daily dose gentamicin in children with cancer.

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.