Chlorprothixene is an antagonist of the following receptors:
* 5-HT, 5-HT, 5-HT: antipsychotic effects, sedation/anxiolysis, antidepressant effect, weight gain
* D, D, D, D, D: antipsychotic effects, sedation, extrapyramidal side effects, prolactin increase, depression, apathy/anhedonia, weight gain
* H: sedation, weight gain
* Muscarinic acetylcholine receptors: anticholinergic effects, inhibition of extrapyramidal side effects
* α-Adrenergic: hypotension, sedation, anxiolysis
Because of its potent serotonin 5-HT and muscarinic acetylcholine receptor antagonism, chlorprothixene causes relatively mild extrapyramidal symptoms. This is in contrast to most other typical antipsychotics. For this reason, chlorprothixene has sometimes been described instead as an atypical antipsychotic.
Chlorprothixene has also been found to act as FIASMA (functional inhibitor of acid sphingomyelinase).