Drug Interaction Report

MONITOR CLOSELY: Coadministration of belzutifan with inhibitors of uridine diphosphate glucuronosyltransferase 2B17 (UGT2B17) and/or CYP450 2C19 may increase the plasma concentrations and the risk and severity of adverse effects, including anemia and hypoxia, of belzutifan. The proposed mechanism is inhibition of UGT 2B17 and/or CYP450 2C19, the isoenzymes responsible for the metabolic clearance of belzutifan. Patients who are dual UGT 2B17 and CYP450 2C19 poor metabolizers are at a greater risk of adverse reactions.

MANAGEMENT: Close monitoring is recommended whenever belzutifan is used concomitantly with a UGT 2B17 and/or CYP450 2C19 inhibitor. Clinical and laboratory monitoring should be considered whenever a UGT 2B17 and/or CYP450 2C19 inhibitor is added to or withdrawn from therapy with belzutifan, and the dosage adjusted as necessary. Consult the manufacturer's product labeling for specific dose adjustment recommendations. Patients should be monitored for development of anemia and hypoxia.

ADJUST DOSING INTERVAL: Food may interfere with the absorption of esomeprazole. The manufacturer reports that the area under the concentration-time curve for esomeprazole following a single 40 mg dose was 33% to 53% lower when administered after food intake as opposed to during fasting conditions.

MANAGEMENT: Esomeprazole should be taken at least one hour before meals. When administered to patients receiving continuous enteral nutrition, some experts recommend that the tube feeding should be interrupted for at least 1 hour before and 1 hour after the dose of esomeprazole is given.