Drug Interaction Report

MONITOR: Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations and risk of adverse effects of ribociclib, which is a substrate of the isoenzyme. Administration of erythromycin, a moderate CYP450 3A4 inhibitor, is predicted to increase ribociclib Cmax and AUC by 1.3- and 1.9-fold, respectively. Data with other, less potent inhibitors, are limited.

MANAGEMENT: Caution is advised when ribociclib is used with CYP450 3A4 inhibitors. Dosage adjustment for ribociclib is not generally considered necessary for suspected interactions with mild to moderate inhibitors. However, some manufacturers of ribociclib recommend that concomitant use with verapamil should be avoided (AU, UK). Patients should be monitored for the development of ribociclib-related adverse effects such as infections, neutropenia, leucopenia, anemia, thrombocytopenia, nausea, vomiting, diarrhea, stomatitis, anorexia, alopecia, fatigue, headache, and abnormal liver function.

GENERALLY AVOID: Pomegranates and grapefruit may increase the systemic exposure to ribociclib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in these fruits. Increased exposure to ribociclib may increase the risk of adverse effects such as infections, neutropenia, leukopenia, anemia, thrombocytopenia, anorexia, nausea, vomiting, diarrhea, stomatitis, alopecia, fatigue, headache, and abnormal liver function may be increased.

MANAGEMENT: Patients receiving ribociclib should avoid consumption of pomegranates or pomegranate juice and grapefruit or grapefruit juice during treatment.