What is known and objective: Voriconazole has significant drug interactions due to metabolism by CYP enzymes. Subtherapeutic voriconazole concentrations associated with concomitant dexamethasone are not well described.
Case description: An 84-year-old male was started on voriconazole for a fungal brain abscess. He was readmitted due to clinical failure thought to be the result of subtherapeutic voriconazole concentrations. Dexamethasone was identified as a potential cause due to its induction of CYP enzymes. This interaction was substantiated by sequential troughs that demonstrated a rise in voriconazole concentrations as dexamethasone was tapered off.
What is new and conclusion: Therapeutic drug monitoring for patients on voriconazole and dexamethasone is essential to prevent suboptimal clinical outcomes.
Keywords: dexamethasone; drug-drug interaction; fungal brain abscess; therapeutic drug monitoring; voriconazole.
© 2016 John Wiley & Sons Ltd.