Pharmacokinetic Characteristics of Caspofungin in Two Pediatric Liver Transplant Patients

Background: The pharmacokinetic characteristics of the antifungal drug caspofungin have not been reported in children. Objective: The aim of this study was to report limited caspofungin pharmacokinetic data for pediatric liver transplant patients. Methods: Two pediatric liver transplant patients, aged 5 years (not dialyzed) and 9 months (dialyzed), were assessed. Using a novel, validated, liquid-phase extraction with high-performance liquid chromatography, we measured plasma caspofungin concentrations from blood samples obtained within a 24-hour period after the patients were given 1 mg/kg IV of caspofungin. Results: Noncompartmental analysis for the nondialyzed patient showed an elimination half-life of 10.7 hours, a volume of distribution of 0.11 L/kg, and a systemic clearance of 0.12 mL/min/kg. Liver enzyme activities increased briefly; the increase may have been due to concomitant graft rejection. For the dialyzed patient, the half-life was 11.7 hours, with an adjusted volume of distribution of 0.18 L/kg and a systemic clearance of 0.24 mL/min/kg. No clinically relevant treatment-related adverse events were noted. Conclusions: Pharmacokinetic data found in the 2 patients in this study are similar to those reported in adults. Until more thorough data are published, caspofungin 1 mg/kg may be considered a reasonable, tolerable dose for children.