Thioridazine anticholinergic activity

Thioridazine Hydrochloride, USP. Thioridazine hydrochloride. IO-[2-( I -mcthyl-2-piperidyl)elhyl -2-(methyl-thio)phenoihiazine monohydrochloride (Mellaril), is a member of the piperidine subgroup of the phenothiazines. The drug has a relatively low tendency to produce EPS. The drug has high anticholinergic activity, and this activity in the striatum, counterbalancing a suiatal DA block, may be responsible for the low EPS. It also has been suggested that there may be increased DA receptor selectivity, which may... 

Cohen BM, Herschel M, Aoba A. Neuroleptic, antimuscarinic, and anticholinergic activity of chlor-promazine, thioridazine and their metabolites. Psychiatry Res 1979 1 199-208. 

Of the systemic antihistamines, the ethanolamines, including diphenhydramine, have significant antimuscarinic activity. In addition, the antipsychotic agents, particularly the phenothiazines such as thioridazine (Mellaril), have well-dociunented anticholinergic properties. Therapeutic doses of tricyclic antidepressants, like amitriptyline hydrochloride (Elavil) and imipramine (Tofranil), produce significant anticholinergic actions and thus have the potential for ocular side effects. 

Thioridazine (50 to 100 mg p.o. t.i.d.) is indicated in psychosis. Thioridazine has potent anticholinergic properties and causes heavy sedation. However, it produces a very low incidence of extrapyramidal reactions such as akathisia, dystonia, parkinsonism, tardive dyskinesia, and neuroleptic malignant syndrome. Thioridazine is metabolized to mesoridazine, which is an active antipsychotic (see Table 19). 

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