Phenothiazine derivatives

Phenothiazine is a benzo derivative of thiazine now most commonly used as an intermediate chemical in the manufacture of various psychiatric drugs. It originally was developed as a synthetic dye in 1883, and it was introduced by DuPont as an insecticide in 1935. It is sometimes used as an antihelminthic in livestock.

Phenothiazine pesticides work by affecting the nervous system of insects, inhibiting the breakdown of acetylcholine by disabling the enzyme acetylcholinesterase. Many of the side effects of phenothiazine neuroleptic antipsychotics are due to their anticholinergic blocking effects.

Phenothiazine-derivative drugs
The term "phenothiazines" is used to describe the largest of the five main classes of neuroleptic antipsychotic drugs. These drugs have antipsychotic and, often, antiemetic properties, although they may also cause severe side effects such as akathisia, tardive dyskinesia, extrapyramidal symptoms, and the rare but potentially fatal neuroleptic malignant syndrome.

The phenothiazine class of neuroleptic antipsychotic psychotropics is closely related to the thioxanthenes which are very similar pharmacologically.

There are three groups of phenothiazine antipsychotics, differing by their chemical structure and their pharmacological effects:

