Drug Interactions between abiraterone and encorafenib

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Coadministration with potent inducers of CYP450 3A4 may significantly decrease the plasma concentrations of abiraterone, which is partially metabolized by the isoenzyme. In healthy subjects administered a single 1000 mg dose of abiraterone following pretreatment with the potent CYP450 3A4 inducer rifampin (600 mg daily for 6 days), mean abiraterone systemic exposure (AUC) decreased by 55%. In addition, when two or more medications with similar adverse effect profiles are given concurrently, the likelihood of experiencing these adverse reactions may be increased. For example, coadministration with other agents that can prolong the QT interval (e.g., apalutamide, encorafenib, enzalutamide) may result in additive effects and an increased risk of ventricular arrhythmias like torsade de pointes.

MANAGEMENT: Concomitant use of abiraterone acetate with potent CYP450 3A4 inducers should generally be avoided. Otherwise, an increase in dosing frequency for abiraterone acetate from once daily to twice daily during the coadministration period may be considered, although this dosage adjustment has not been studied clinically. The dosage should be adjusted back to the previous level when the CYP450 3A4 inducer is discontinued. If abiraterone acetate is part of a combination pill, the regimen may need to be split into its individual components to allow for changes in abiraterone acetate dosing without affecting the other component(s). If the CYP450 3A4 inducer also carries a risk of prolonging the QT interval, then obtaining more frequent electrocardiograms (ECGs) to monitor the QT interval may be advisable. Patients should be counseled to seek immediate medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, syncope, palpitations, irregular heartbeat, and/or shortness of breath.