Drug Interactions between leniolisib and mavacamten

Grapefruit juice may increase the blood levels of mavacamten and increase the risk of heart failure, a condition where the heart is unable to pump blood adequately to meet the body's needs. Your risk may be further increased if you develop a serious infection or irregular heartbeat during treatment with mavacamten. You should avoid the consumption of grapefruit and grapefruit juice while taking this medication. Talk to your doctor if you have any questions or concerns. You should seek medical attention if you experience signs and symptoms of heart failure such as shortness of breath, chest pain, fatigue, swelling in your legs, palpitations, or rapid weight gain. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with inhibitors of CYP450 3A4 including grapefruit or grapefruit juice may increase the plasma concentrations of leniolisib, which undergoes extensive CYP450 3A4-mediated first-pass metabolism in the gut wall and liver. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients who regularly consume grapefruit or grapefruit juice should be monitored for adverse effects and altered plasma concentrations of leniolisib. Some authorities recommend to avoid grapefruit products during leniolisib treatment (UK).