About Zuclopenthixol Thioxanthene derivative, A typical antipsychotic neuroleptic drug. Mechanism of Action of Zuclopenthixol Zuclopenthixol exerts its antipsychotic action by blocking post synaptic Dopamine receptor in the limbic system. It is a potent antagonist of D1 and D2 receptors. Zuclopenthixol also has high affinity for alpha1-adrenergic and 5-HT2 receptors. It has weaker histamine H1 receptor blocking activity, and even lower affinity for muscarinic cholinergic and alpha2 adrenergic receptors and depresses many hypophyseal and hypothalamic hormones Dopamine is involved in transmitting signals between brain cells. When there is an excess amount of dopamine in the brain it causes over-stimulation of dopamine receptors. These receptors normally act to modify behaviour and over-stimulation in psychotic illness. Zuclopenthixol blocks these receptors and stops them becoming over-stimulated, thereby helping to control psychotic illness.