Factors affecting voriconazole plasma concentrations in patients with invasive fungal infections.

Objective: This study retrospectively analyzed the medical records of patients with invasive fungal infections treated with voriconazole in a teaching hospital in order to identify the factors affecting plasma concentrations of voriconazole.

Methods: Patients treated with voriconazole for invasive fungal infection at the oncology department of the Samsung Medical Center, which is a tertiary teaching hospital located in Seoul, Korea, between January 2010 and May 2012 were statistically analyzed for the identification of factors affecting plasma concentrations of voriconazole.

Results: Of the 64 patients analyzed, 3 patients who were also treated with cytochrome P450 (CYP) 2C19 inducers showed a statistically lower plasma concentration of voriconazole compared to the other 61 patients (p = 0.034). Factors such as sex, underlying disease, age, and voriconazole dosage were not significantly associated with the median plasma concentrations of voriconazole. The different administration routes of voriconazole were also not significantly associated with the median plasma concentration, but there was a tendency for higher plasma concentrations in 28 patients receiving the drug intravenously compared to 36 patients who received it orally.

Conclusions: We found that patients with invasive fungal infections receiving voriconazole and CYP2C19 inducers concomitantly had significantly lower plasma concentrations of voriconazole compared to the other patients. In addition, there was a tendency for patients to have a higher plasma concentration of voriconazole when it was administered intravenously. However, additional prospective studies are needed to confirm these results and apply them to routine clinical practice. In the future it will be important to monitor plasma concentrations of voriconazole while considering the influence of various factors that could affect the concentrations.