In a trial on the CYP2D6 enzyme, giving dextromethorphan together with abiraterone acetate 1,000 mg daily and prednisone 5 mg twice daily raised the level of dextromethorphan in the body. Its peak level (Cmax) went up 2.8-fold and the total amount in the blood over time (AUC) went up 2.9-fold.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.