Drug Interactions between mobocertinib and nisoldipine

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of mobocertinib. The mechanism may involve inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit juice. Based on drug interaction studies using model-informed approaches, coadministration of mobocertinib with multiple doses of itraconazole or ketoconazole (strong CYP450 3A4 inhibitors) is predicted to increase the steady-state combined molar AUC (systemic exposure) of mobocertinib and its active metabolites by 374% to 419%, while coadministration with multiple doses of a moderate CYP450 3A4 inhibitor is predicted to increase this value by approximately 100% to 200%. 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. Elevated plasma concentrations of mobocertinib may increase the risk for adverse effects such as QT prolongation, heart failure or reduced ejection fraction, cardiomyopathy, heart block, diarrhea, rash, stomatitis, fatigue, and musculoskeletal pain.

MANAGEMENT: Patients should avoid consumption of grapefruit and grapefruit juice during treatment with mobocertinib.

GENERALLY AVOID: The consumption of grapefruit juice may be associated with significantly increased plasma concentrations of some calcium channel blockers (CCBs) when they are administered orally. 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 been reported with the dihydropyridine CCBs (in roughly decreasing order of magnitude) felodipine, nisoldipine, nifedipine, and nimodipine, often with a high degree of interindividual variability. Grapefruit juice caused more than twofold increases in felodipine, nifedipine, and nisoldipine AUCs.

MANAGEMENT: The manufacturers of nifedipine and nisoldipine recommend avoiding grapefruit juice. Patients treated orally with other calcium channel blockers should be advised to avoid consumption of large amounts of grapefruits and grapefruit juice to prevent any undue fluctuations in serum drug levels. Increased effects on blood pressure may persist for up to 4 days after the consumption of grapefruit juice. Monitoring for calcium channel blocker adverse effects (e.g., headache, hypotension, syncope, tachycardia, edema) is recommended.