Thioridazine

What is thioridazine?

First generation ‘typical’ antipsychotics such as thioridazine are an older class of antipsychotic than second generation ‘atypical’ antipsychotics. They are used primarily to treat positive symptoms including the experiences of perceptual abnormalities (hallucinations) and fixed, false, irrational beliefs (delusions). First generation antipsychotics may cause side effects which can differ depending on which antipsychotic is being administered and on individual differences in reaction to the drug. Reactions may include dyskinesias such as repetitive, involuntary, and purposeless body or facial movements, Parkinsonism (cogwheel muscle rigidity, pill-rolling tremor and reduced or slowed movements), akathisia (motor restlessness, especially in the legs, and resembling agitation) and dystonias such as muscle contractions causing unusual twisting of parts of the body, most often in the neck. These effects are caused by the dopamine receptor antagonist action of these drugs.

What is the evidence for thiroidazine?

Compared to placebo, high quality evidence shows thioridazine improves global state and increases study retention in the short term. Moderate quality evidence suggests there may also be reduced relapse rates, however thioridazine may cause dry mouth, constipation and vomiting. Moderate to low quality evidence suggests thioridazine may also be sedating, may increase tremor, and may increase the use of antiparkinsonian drugs in the short term.

Compared to other first generation antipsychotics, high quality evidence shows no differences in global state with thioridazine. Moderate quality evidence suggests no differences in study retention for any reason, although there may be more people leaving the study early with thioridazine due to adverse events in the short term. Moderate quality evidence suggests there may be less short term use of antiparkinsonian drugs with thioridazine, with less rigidity in the medium term. However, there may be increased risk of any cardiac adverse effects, dry mouth, and short term vomiting and nausea with thioridazine.

Compared to second generation antipsychotics, moderate to high quality evidence shows no differences in global state or study retention with thioridazine. Moderate to low quality evidence suggests no differences in adverse effects.

November 2019

Last updated at: 2:11 am, 14th November 2019
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Title Colour Legend:
Green - Topic summary is available.
Orange - Topic summary is being compiled.
Red - Topic summary has no current systematic review available.