Drug Interaction Report

MONITOR: Coadministration with rucaparib may increase the plasma concentrations and the risk of adverse effects of drugs that are substrates of CYP450 2C9. The proposed mechanism is decreased clearance due to rucaparib-mediated inhibition of CYP450 2C9. In a clinical study, rucaparib increased S-warfarin Cmax and AUC by 1.05- and 1.49-fold, respectively.

MANAGEMENT: Caution is advised if rucaparib is used concomitantly with drugs that are substrates of CYP450 2C9, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring should be considered whenever rucaparib is added to or withdrawn from therapy with these drugs. Patients should be monitored for the development of adverse effects.

ADJUST DOSING INTERVAL: Food may reduce the oral absorption and bioavailability of zafirlukast. In two separate studies, one using a high-fat and the other a high-protein meal, administration of zafirlukast with food reduced the mean bioavailability by approximately 40%.

MANAGEMENT: To ensure maximal oral absorption, zafirlukast should be administered at least 1 hour before or 2 hours after meals.