S-(+)-O-Desmethyl Venlafaxine-D6 is an isotope labelled compound of S-(+)-O-Desmethyl Venlafaxine (D296510), a metabolite of Venlafaxine, a selective serotonin noradrenaline reuptake inhibitor, used as an antidepressant. Also used as high-dose venlafaxine treatment in depressed patient with a genetic CYP2D6 deficiency.