Drug Interaction Report

MONITOR: Coadministration with inhibitors of CYP450 2C9 may increase the plasma concentrations of torsemide. The interaction has not been evaluated in pharmacokinetic studies; however, torsemide has been shown to undergo metabolism by CYP450 2C9.

MANAGEMENT: Caution is advised when torsemide is prescribed with CYP450 2C9 inhibitors. Patients should be monitored for potentially increased adverse effects such as dehydration, hypotension, electrolyte imbalances, hyperglycemia, tinnitus, and hearing loss.

ADJUST DOSING INTERVAL: Food reduces the oral absorption and bioavailability of voriconazole. According to the product labeling, administration of multiple doses of voriconazole with high-fat meals decreased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) by 34% and 24%, respectively, when the drug is administered as a tablet, and by 58% and 37%, respectively, when administered as the oral suspension.

MANAGEMENT: To ensure maximal oral absorption, voriconazole tablets and oral suspension should be taken at least one hour before or after a meal.