Mezlocillin pharmacokinetics in pediatric oncology patients.

The pharmacokinetics of mezlocillin were studied in 31 children (age, 2 to 19 years) with malignancies and normal renal and hepatic functions. Mezlocillin was administered intravenously over 30 min every 4 h at doses ranging from 12.2 to 125 mg/kg. Blood samples were obtained over one dosage interval at steady state. For all patients, the mean clearance was 0.21 +/- 0.11 liter/h per kg, the mean distribution volume was 0.26 +/- 0.13 liter/kg, and the mean elimination half-life was 0.97 +/- 0.51 h. Trough concentrations were 23.0 +/- 29.9 mg/liter before the dose was administered and 20.4 +/- 27.5 mg/liter at the end of the dosing interval. Peak concentrations averaged 245 +/- 90.4 mg/liter, and average concentrations for the dosing interval were 83.7 +/- 40.4 mg/liter. There were no apparent effects of sex, malignancy, age, or dose on either the kinetic parameters or plasma concentrations. Overall, the disposition parameters for mezlocillin in this patient group were comparable to those reported in adults.