What to watch with CYP2D6 and sleep?

CYP2D6 is a key drug-metabolizing enzyme that breaks down many psychotropic medications, including antidepressants like trazodone, mirtazapine, or amitriptyline, which are often used off-label for sleep. Depending on your genotype (poor, intermediate, normal, or ultrarapid metabolizer), drug efficacy and side effects can differ significantly. Poor metabolizers may experience excessive sedation, dizziness, or next-day drowsiness even at low doses, while ultrarapid metabolizers might find the medication ineffective or short-acting. Importantly, there is no strong evidence that CYP2D6 directly affects natural sleep regulation; its relevance is limited to medication contexts. A DNA test alone should never prompt dose changes without medical supervision. Also consider drug-drug interactions (e.g., with beta-blockers, opioids). The evidence is primarily mechanistic/pharmacokinetic, not sleep-specific.