Brexpiprazole dose adjustment for poor metabolizers of CYP2D6?

Brexpiprazole dose adjustment for poor metabolizers of CYP2D6?

• A. Increase dose by 50%
• B. No adjustment
• C. Reduce dose by 50%
• D. Stop therapy

Answer: (C)

Understanding how genetics affect drug metabolism is essential. Brexpiprazole is processed by enzymes including CYP2D6. People who are poor metabolizers for CYP2D6 have reduced enzyme activity, so the drug stays in the body longer and at higher levels than in normal metabolizers. To avoid excessive exposure and potential adverse effects, the dose should be reduced by about half in these patients. If there are additional factors, such as concomitant strong inhibitors of CYP2D6, further adjustments or monitoring may be needed, but the baseline change is a 50% dose reduction. Increasing the dose would raise exposure and risk; not adjusting could lead to toxicity; stopping therapy is not indicated unless there are other clinical reasons.

Understanding how genetics affect drug metabolism is essential. Brexpiprazole is processed by enzymes including CYP2D6. People who are poor metabolizers for CYP2D6 have reduced enzyme activity, so the drug stays in the body longer and at higher levels than in normal metabolizers. To avoid excessive exposure and potential adverse effects, the dose should be reduced by about half in these patients. If there are additional factors, such as concomitant strong inhibitors of CYP2D6, further adjustments or monitoring may be needed, but the baseline change is a 50% dose reduction. Increasing the dose would raise exposure and risk; not adjusting could lead to toxicity; stopping therapy is not indicated unless there are other clinical reasons.