An active metabolite of thioridazine; formed via sulfoxidation of thioridazine by CYP2D6 in human liver microsomes; binds to histamine H1, dopamine D2, muscarinic acetylcholine, and α1- and α2-adrenergic receptors (Kds = 1.8, 19, 69, 2, and 1,600 nM, respectively); prevents mescaline-induced hyperactivity in mice at 10, 30, and 45 mg/kg