Evidence check: CYP2D6 in the context of Müdigkeit

CYP2D6 is a key enzyme metabolizing many drugs, including opioids, antidepressants, and antipsychotics. Genetic variants can alter enzyme activity from poor to ultrarapid metabolizer. In the context of fatigue, the link is indirect: if a drug is not properly metabolized due to CYP2D6 status, side effects like fatigue may occur (e.g., elevated drug levels from antidepressants). Conversely, lack of efficacy (e.g., from opioid painkillers) can perpetuate exhaustion. Direct evidence linking CYP2D6 variants to fatigue as a standalone symptom is weak – the associations are pharmacogenetic, not a genetic predisposition for fatigue. Consumer DNA tests can offer clues but miss rare variants and do not replace medical advice. Persistent fatigue warrants a thorough clinical workup.