Drug Interaction Report

MONITOR: Coadministration with inducers of CYP450 3A4 and/or P-glycoprotein may decrease the plasma concentrations of gilteritinib, which is a substrate of both the isoenzyme and the efflux transporter. When gilteritinib was coadministered with rifampin, a combined P-gp and potent CYP450 3A4 inducer, gilteritinib peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by 30% and 70%, respectively, compared to administration of gilteritinib alone. Reduced efficacy of gilteritinib may occur. The interaction has not been studied with other, less potent inducers or lone inducers of CYP450 3A4 or P-gp.

MANAGEMENT: The potential for diminished pharmacologic effects of gilteritinib should be considered during coadministration with CYP450 3A4 and/or P-gp inducers. Alternative treatments may be required if an interaction is suspected.

ADJUST DOSING INTERVAL: Certain penicillins may exhibit reduced gastrointestinal absorption in the presence of food. The therapeutic effect of the antimicrobial may be reduced.

MANAGEMENT: The interacting penicillin should be administered one hour before or two hours after meals. Penicillin V and amoxicillin are not affected by food and may be given without regard to meals.