Drug Interaction Report

Coadministration with niraparib may decrease the plasma concentrations of drugs that are substrates of the CYP450 1A2 isoenzyme. At high concentrations, niraparib is able to weakly induce CYP450 1A2. If niraparib is used in combination with substrates of CYP450 1A2, particularly those with a narrow therapeutic range (e.g., clozapine, theophylline, ropinirole), then monitoring for signs and symptoms of reduced exposure to the CYP450 1A2 substrate should be considered.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of axitinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

MANAGEMENT: Patients treated with axitinib should avoid consumption of grapefruit, grapefruit juice, and any supplement containing grapefruit extract. Axitinib may be administered with or without food.