Intravenous Voriconazole Therapy in a Preterm Infant

A preterm infant younger than 3 months developed a disseminated fluconazole-resistant Candida albicans infection that was treated with liposomal amphotericin B for 52 days, followed by the combination of intravenous voriconazole and liposomal amphotericin B for an additional 19 days. The infant received concomitant phenobarbital throughout the hospital stay. The infection resolved after addition of voriconazole to the treatment regimen. Intravenous voriconazole was begun at a high dosage, 6 mg/kg every 12 hours, for anticipated developmental and drug-induced changes in volume of distribution and clearance. On day 4 of therapy, serum concentrations of voriconazole were 3.27 microg/ml immediately after infusion and 0.33 microg/ml 6 hours after infusion. These levels were significantly lower than those achieved in adult pharmacokinetic and safety studies. After the infant's dosage was increased to 6 mg/kg every 8 hours, serum concentrations were 5.33 microg/ml 30 minutes after infusion and 2.67 microg/ml 6 hours after infusion. These levels were similar to those observed in adults. Intravenous voriconazole 6 mg/kg every 8 hours was administered safely, with concomitant phenobarbital therapy, in this preterm infant with developmentally diminished renal function.