Drug Interaction Report

MONITOR: Theoretically, coadministration with anagrelide may increase the plasma concentrations and the risk of toxicity of drugs that are substrates of CYP450 1A2. The proposed mechanism, based on in vitro data, is decreased clearance due to anagrelide-mediated inhibition of CYP450 1A2 metabolism.

MANAGEMENT: Until more information is available, caution is advised if anagrelide is used concomitantly with drugs that are substrates of CYP450 1A2, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever anagrelide is added to or withdrawn from therapy. Patients should be monitored for the development of adverse effects.

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.