{"CYP2D6": "Decreased metabolism of venlafaxine to the active metabolite O-desmethylvenlafaxine (desvenlafaxine) and greatly decreased O-desmethylvenlafaxine:venlafaxine ratio as compared to CYP2D6 normal and intermediate metabolizers. The clinical impact of increased venlafaxine and decreased O-desmethylvenlafaxine:venlafaxine ratio in CYP2D6 poor metabolizers is unclear, but CYP2D6 PM genotype has been associated with adverse effects."}