Factors associated with subtherapeutic levels of oral posaconazole tablet: a detailed analysis from a tertiary care center in India.

OBJECTIVES

Posaconazole is a broad-spectrum triazole antifungal, with activity against various clinically important fungi. The delayed release (DR) tablet of posaconazole has been shown to have a superior pharmacokinetic profile in comparison with the oral suspension.

METHODS

We retrospectively analyzed the factors associated with posaconazole levels <1.25 μg/ml in 164 patients receiving the DR tablet for therapeutic purposes.

RESULTS

Of the 164 patients, 53 (32.3%) showed subtherapeutic trough levels of posaconazole. The use of proton pump inhibitors (95% CI 1.41-3.91; P-value = 0.028) and the presence of diarrhea (95% CI 1.95-6.93; P-value = 0.001) were significantly associated with subtherapeutic levels. A total of 13 of the 21 patients receiving posaconazole tablets through a nasogastric tube had therapeutic levels.

CONCLUSION

This is the largest study from India that analyzed factors associated with subtherapeutic levels of the DR tablet of posaconazole. These findings reinforce the importance of therapeutic drug monitoring. Unlike in previous studies, obesity and hypoalbuminemia were not found to be significant factors in our settings. The use of proton pump inhibitors and diarrhea remained significant factors, as found in previous studies. Administering the DR tablet of posaconazole through a nasogastric tube may be a viable option.