Drug Interaction Report

GENERALLY AVOID: Coadministration with rolapitant may increase the plasma concentrations of drugs that are substrates of the P-glycoprotein (P-gp) efflux transporter. When a 0.5 mg dose of digoxin, a P-gp probe substrate, was administered with a 180 mg dose of rolapitant, digoxin peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 70% and 30%, respectively.

MANAGEMENT: Concomitant use of rolapitant with drugs that are P-gp substrates should generally be avoided. If concomitant administration is unavoidable, caution is advised, particularly with drugs that have a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever rolapitant is added to or withdrawn from therapy.

GENERALLY AVOID: Grapefruit and grapefruit juice may significantly increase the plasma concentrations of orally administered ranolazine. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Because ranolazine prolongs QT interval in a dose-dependent manner, high plasma levels of ranolazine may increase the risk of ventricular arrhythmias such as ventricular tachycardia, ventricular fibrillation, and torsade de pointes.

MANAGEMENT: Patients treated with ranolazine should avoid consumption of grapefruit juice and other grapefruit products if possible. Otherwise, the dosage of ranolazine should be limited to 500 mg twice a day.