CYP2D6 and Alzheimer disease: In the venlafaxine group, the following CYP2D6 substrates were also administered concomitantly: analgesics (38.3%), antipsychotics (26.1%) and AD (17.4%), of which tramadol (29.6%), risperidone (13.0%), quetiapine (12.2%) and amitriptyline (12.2%) were the most-common active substances.