Drug Interactions between amoxicillin / clarithromycin / vonoprazan and bosutinib

GENERALLY AVOID: Coadministration with potent and moderate inhibitors of CYP450 3A4 may significantly increase the plasma concentrations of bosutinib, which is primarily metabolized by the isoenzyme. In 24 healthy volunteers, administration of a single 100 mg dose of bosutinib with the potent CYP450 3A4 inhibitor ketoconazole (400 mg/day for 5 days) under fasting conditions resulted in a 5.2-fold increase in bosutinib peak plasma concentration (Cmax) and 8.6-fold increase in systemic exposure (AUC) compared to administration of bosutinib alone. Ketoconazole also decreased the mean apparent clearance of bosutinib by approximately 9-fold and increased the mean terminal half-life from 46.2 hours to 69.0 hours.

MANAGEMENT: Concomitant use of bosutinib with potent or moderate CYP450 3A4 inhibitors should generally be avoided. Some authorities recommend avoiding concomitant use of bosutinib during and for 2 weeks after treatment with itraconazole. If use of a potent or moderate CYP450 3A4 inhibitor is required, an interruption or a dosage reduction of bosutinib therapy should be considered.

MONITOR: Coadministration with inhibitors of CYP450 3A4 and/or P-glycoprotein (P-gp) may increase the plasma concentrations of bosutinib, which is a substrate of the isoenzyme and efflux transporter. In 24 healthy volunteers, administration of a single 100 mg dose of bosutinib with the potent CYP450 3A4 and P-gp inhibitor ketoconazole (400 mg/day for 5 days) under fasting conditions resulted in a 5.2-fold increase in bosutinib peak plasma concentration (Cmax) and 8.6-fold increase in systemic exposure (AUC) compared to administration of bosutinib alone. Ketoconazole also decreased the mean apparent clearance of bosutinib by approximately 9-fold and increased the mean terminal half-life from 46.2 hours to 69.0 hours. No data are available for use with less potent CYP450 3A4 inhibitors or P-gp inhibitors.

MANAGEMENT: Caution is advised when bosutinib is used with CYP450 3A4 or P-gp inhibitors. Patients should be monitored more closely for development of adverse effects such as diarrhea, nausea, vomiting, abdominal pain, myelosuppression, hepatotoxicity, and fluid retention (e.g., pericardial effusion, pleural effusion, pulmonary edema, peripheral edema).

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.