Drug Interactions between macitentan and Nexterone

Amiodarone may be taken with or without food but should be taken at the same way each time. You should avoid consuming grapefruits and grapefruit juice while taking amiodarone. Do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor. Grapefruit can raise the levels of amiodarone in your body and lead to dangerous side effects. This can affect the rhythm of your heart. Call your doctor if you have symptoms of irregular heartbeat, chest tightness, blurred vision or nausea.

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Coadministration with grapefruit juice may increase the plasma concentrations of macitentan, which is primarily metabolized by CYP450 3A4. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. The interaction has not been studied with grapefruit juice but has been reported for ketoconazole, a potent CYP450 3A4 inhibitor. In ten healthy subjects, coadministration of a single 10 mg oral dose of macitentan on day 5 of treatment with ketoconazole (400 mg daily for 24 days) resulted in an approximately 2-fold increase in macitentan systemic exposure compared to administration alone. However, the clinical significance of the interaction is unclear. 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: Until further information is available, patients receiving macitentan therapy should avoid the consumption of grapefruit or grapefruit juice.