Pharmacokinetics of fluconazole in immune-compromised children with leukemia or other hematologic diseases.

STUDY OBJECTIVE: To describe the pharmacokinetics of fluconazole in immune-compromised children with leukemia or other hematologic disease. DESIGN: Prospective. SETTING: Children's Health Care-Minneapolis hematology/oncology inpatient ward and outpatient clinic. PATIENTS: Ten immune-compromised children (mean +/- SD age 7.4 +/- 4.0 yrs, weight 31.6 +/- 25.9 kg) with leukemia or other hematologic disease. INTERVENTIONS: Serum was sampled before and after a single 6-mg/kg intravenous dose and after seven oral 3-mg/kg doses of fluconazole. MEASUREMENTS AND MAIN RESULTS: Mean (SD) pharmacokinetics were distribution half-life 1.67 (1.25) hours, elimination half-life 15.62 (3.21) hours, total body clearance 0.63 (0.19) ml/min/kg, volume of distribution for the central compartment 0.56 (0.10) L/kg, volume of distribution at steady state 0.77 (0.12) L/kg, absorption half-life 0.41 (0.26) hour, and oral bioavailability 0.92 (0.09). Volume of distribution for the central compartment was highly correlated with body surface area (r2 = 0.891) and weight (r2 = 0.949). Volume of distribution at steady state correlated with body surface area (r2 = 0.986), and total body clearance correlated with body surface area (r2 = 0.867). CONCLUSIONS: Fluconazole elimination was well described using a two-compartment model. Oral absorption was rapid and nearly complete. Children have a larger volume of distribution for the central compartment and faster elimination rate than adults. Body surface area and weight are important factors in determining pharmacokinetics in these patients.