Tricyclic antidepressant and anxiolytic compound. Acts as a high affinity sigma receptor agonist, primarily at the sigma1 subtype, but also at the sigma2 subtype with somewhat lower affinity. Shows a low to moderate antagonistic affinity for the D2, 5-HT2, H1, H2, and muscarinic acetylcholine receptors. H1 and H2 receptor antagonism account for its antihistamine effects, and muscarinic acetylcholine receptor antagonism is responsible for its anticholinergic properties.