Drug Interactions between amoxicillin / clarithromycin / vonoprazan and pexidartinib

GENERALLY AVOID: Coadministration of pexidartinib with strong CYP450 3A4 inhibitors and/or uridine diphosphate glucuronosyltransferase (UGT) inhibitors may significantly increase the plasma concentrations and the incidence and severity of adverse effects of pexidartinib, including potentially fatal hepatotoxicity. The proposed mechanism is inhibition of CYP450 3A4 and/or UGT, the primary isoenzymes responsible for the metabolic clearance of pexidartinib. Concomitant administration of itraconazole, a strong CYP450 3A4 inhibitor, increased pexidartinib peak plasma concentration (Cmax) and systemic exposure (AUC) by 48% and 70%, respectively. Coadministration with probenecid, a UGT inhibitor, increased pexidartinib Cmax and AUC by 5% and 60%, respectively.

MANAGEMENT: The use of pexidartinib with strong CYP450 3A4 inhibitors and/or UGT inhibitors should generally be avoided. If concomitant use is required, the dose of pexidartinib should be reduced according to the manufacturer's recommendations. If concomitant use of a strong CYP450 3A4 inhibitor or UGT inhibitor is discontinued, the dose of pexidartinib may be increased, after 3 plasma half-lives of the strong CYP450 3A4 inhibitor or UGT inhibitor, to the dose that was used prior to starting the strong CYP450 3A4 inhibitor or UGT inhibitor.

GENERALLY AVOID: Coadministration with moderate inducers of CYP450 3A4 may significantly decrease the plasma concentrations of vonoprazan, which is metabolized by the isoenzyme. When coadministered with moderate CYP450 3A4 inducers, vonoprazan systemic exposure (AUC) is predicted to decrease by 50%. Reduced efficacy of vonoprazan may occur.

MANAGEMENT: According to the manufacturer, concomitant use of vonoprazan with moderate CYP450 3A4 inducers should be avoided.

Although some in vitro data indicate synergism between macrolide antibiotics and penicillins, other in vitro data indicate antagonism. When these drugs are given together, neither has predictable therapeutic efficacy. Data are available for erythromycin, although theoretically this interaction could occur with any macrolide. Except for monitoring of the effectiveness of antibiotic therapy, no special precautions appear to be necessary.