Drug Interaction Report

GENERALLY AVOID: Coadministration of erdafitinib with potent inhibitors of CYP450 2C9 or 3A4 may increase the plasma concentrations and risk of toxicity of erdafitinib, which is a substrate of these isoenzymes. When coadministered with fluconazole, a strong CYP450 2C9 inhibitor and moderate CYP450 3A4 inhibitor, erdafitinib mean ratios for Cmax and AUC were 121% and 148%, respectively, relative to erdafitinib alone. Similarly, when coadministered with itraconazole, a strong CYP450 3A4 inhibitor, erdafitinib mean ratios for Cmax and AUC were 105% and 134%, respectively, relative to erdafitinib alone.

MANAGEMENT: Coadministration of erdafitinib with potent inhibitors of CYP450 2C9 or 3A4 should generally be avoided. If concomitant use is unavoidable, patients should be closely monitored for the development of adverse effects. Dosage adjustments as well as clinical and laboratory monitoring of erdafitinib should be considered whenever a CYP450 2C9 or 3A4 inhibitor is added to or withdrawn from therapy.

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.