Phenothiazines are the largest of the 5 main classes of antipsychotic drugs. Although these drugs are generally effective, there are often serious side-effects including Parkinsonism and sedation (especially in the early stages of treatment).

There are three groups of phenothiazines, differing by their chemical structure and their pharmacological effects: -

Group	Autonomic	Example	Sedative	Extrapyramidal side-effect
Aliphatic compounds
	moderate	Chlorpromazine(Thorazine, Largactil)	strong	moderate
		Promazine	moderate	moderate
		Triflupromazine (Vesprin)	strong	moderate/strong
		Methotrimeprazine (Nozinan)
Piperidines	strong	Mesoridazine	strong	weak
		Thioridazine (Mellaril)	strong	weak
Piperazines	weak	Fluphenazine	weak/moderate	strong
		Perphenazine	weak/moderate	strong
		Prochlorperazine (Stemetil)
		Trifluoperazine (Stelazine)	moderate	strong