Influence of malignancy on the pharmacokinetics of vancomycin in infants and children

This prospective, controlled study evaluates the influence of malignancy on the pharmacokinetics and dosage requirements of vancomycin in 33 infants and children with cancer (age 5.72 +/- 4.11 years, mean +/- SD) compared with 31 patients without cancer (age 4.18 +/- 5.10 years) using a two-compartment Bayesian pharmacokinetic program. Patients in the malignancy group required a vancomycin dosage regimen of 71.5 +/- 13.9 mg/kg/day to attain a mean peak serum vancomycin concentration (SVC) of 22.38 +/- 4.54 mg/liter and a mean trough SVC of 6.84 +/- 2.78 mg/liter. Patients without cancer in the control group required a mean vancomycin dosage regimen of 50.2 +/- 13.0 mg/kg/day to attain a mean peak SVC of 21.70 +/- 6.70 mg/liter and a mean trough SVC of 8.05 +/- 3.01 mg/liter. Comparative analysis of pharmacokinetic data revealed an increase in vancomycin clearance (0.149 +/- 0.028 liter/hour/kg) in the malignancy group as compared with that (0.114 +/- 0.031 liter/hour/kg) in the control group. There were no significant differences with respect to the mean values of volume of distribution between two groups (0.638 +/- 0.079 liter/kg vs. 0.618 +/- 0.102 liter/kg). Analysis of the predictive performance of the Bayesian program indicated that final sets of peak and trough SVCs were predicted with minimal bias and accurate precision in both study groups. This study showed that the presence of malignancy in infants and children increased vancomycin clearance resulting in larger dosage requirements.