Drug Interaction Report

GENERALLY AVOID: Coadministration with potent inducers of CYP450 3A4 and/or P-glycoprotein (P-gp) may significantly decrease the plasma concentrations of idelalisib, which is a substrate of both the isoenzyme and efflux transporter. In healthy volunteers, administration of a single 150 mg dose of idelalisib with the potent CYP450 3A4 and P-gp inducer rifampin (600 mg daily for 8 days) decreased mean idelalisib peak plasma concentration (Cmax) by 58% and systemic exposure (AUC) by 75%.

MANAGEMENT: Concomitant use of idelalisib with potent CYP450 3A4 or P-gp inducers such as carbamazepine, enzalutamide, mitotane, phenobarbital, phenytoin, rifampin, and St. John's wort should generally be avoided due to the potential for reduced efficacy.