Zuclopenthixol dihydrochloride is an antagonist at D1 and D2 dopamine receptors. Zuclopenthixol also has high affinity for alpha1-adrenergic and 5-HT2 receptors, but it has weaker histamine H1 receptor blocking activity, and even lower affinity for muscarinic cholinergic and alpha2-adrenergic receptors. lt is the cis-isomer of clopenthixol. It is an antipsychotic drug belonging the thioxanthene class.