Posaconazole therapeutic drug monitoring (TDM) is widely utilized to assess therapeutic efficacy and safety; however, clinical effects of very high serum concentrations are unknown. A retrospective review of 90 patients receiving posaconazole for treatment or prophylaxis of invasive fungal infections with serum concentrations ≥3000 ng/mL from 1/1/2019 to 4/30/2021 evaluated the incidence and type of adverse drug reactions (ADRs). Symptomatic ADRs were very common in patients with posaconazole concentrations of ≥5000 ng/mL and 3000-4999 ng/mL (80% vs. 58.8%; P = 0.31). Posaconazole TDM should be performed for both treatment and prophylaxis indications and dose decrease for serum concentrations >3000 ng/mL should be considered.
Keywords: drug monitoring; posaconazole; posaconazole toxicity; supratherapeutic posaconazole; triazoles.
Drug level monitoring is commonly used to evaluate appropriate dosing and effectiveness of posaconazole, a medication used to treat fungal infections. Patients with high levels commonly had side effects. Posaconazole monitoring should be completed, and doses reduced when levels are high.
© The Author(s) 2023. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.