Voriconazole therapeutic drug monitoring
A 2-year-old boy being treated for acute lymphoblastic leukemia developed confusion and was found to have a mass on cranial imaging.Aneurosurgical biopsy revealed an aspergilloma. Intravenous (iv) voriconazole is administered at 8 mg/kg per dose twice daily. After 10 days of therapy, 2 voriconazole peak concentrations from central venous catheter samples drawn 1 hour after infusion were 10.8 and 12.2 μg/mL. After dose reduction to 6 mg/kg per dose iv twice daily, peripheral vein trough concentration was 0.3 μg/mL. After increasing the dose to 10 mg/kg per dose iv twice daily, a subsequent trough concentration is 2.0 μg/mL. The Pediatric Infectious DiseasesConsultant is asked (1) howto interpret the variability of serum voriconazole concentrations and (2) when (and how) to check subsequent concentrations.