Chlorpromazine (Thorazine): Essential Clinical Profile

1. Mechanism of Action & Pharmacology Chlorpromazine is a first-generation phenothiazine antipsychotic and antiemetic. It blocks postsynaptic dopamine D2 receptors in the mesolimbic system, reducing psychosis but causing extrapyramidal symptoms (EPS). Dopamine blockade in the chemoreceptor trigger zone produces antiemetic effects. It exhibits strong anticholinergic and alpha-1-adrenergic receptor blocking properties, causing sedation and cardiovascular effects like profound hypotension.

2. Pharmacokinetics & Metabolism Oral bioavailability averages 32% due to extensive first-pass metabolism. It is 90% to 99% plasma protein-bound, and undergoes biphasic metabolism with a terminal half-life of 30 hours. Metabolism is primari ...