BACKGROUND

Pimozide, formulated in the 1960s, continues to be marketed for the care of people with schizophrenia or related psychoses such as delusional disorder. It has been associated with cardiotoxicity and sudden unexplained death. Electrocardiogram monitoring is now required before and during use.

OBJECTIVES

To review the effects of pimozide for people with schizophrenia or related psychoses in comparison with placebo, no treatment or other antipsychotic medication.A secondary objective was to examine the effects of pimozide for people with delusional disorder.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group's Register (28 January 2013).

SELECTION CRITERIA

We sought all relevant randomised clinical trials (RCTs) comparing pimozide with other treatments.

DATA COLLECTION AND ANALYSIS

Working independently, we inspected citations, ordered papers and then re-inspected and assessed the quality of the studies and of extracted data. For homogeneous dichotomous data, we calculated the relative risk (RR), the 95% confidence interval (CI) and mean differences (MDs) for continuous data. We excluded data if loss to follow-up was greater than 50%. We assessed risk of bias for included studies and used GRADE to rate the quality of the evidence.

MAIN RESULTS

We included 32 studies in total: Among the five studies that compared pimozide versus placebo, only one study provided data for global state relapse, for which no difference between groups was noted at medium term (1 RCT n = 20, RR 0.22 CI 0.03 to 1.78, very low quality of evidence). None of the five studies provided data for no improvement or first-rank symptoms in mental state. Data for extrapyramidal symptoms demonstrate no difference between groups for Parkinsonism (rigidity) at short term (1 RCT, n = 19, RR 5.50 CI 0.30 to 101.28, very low quality of evidence) or at medium term (1 RCT n = 25, RR 1.33 CI 0.14 to 12.82, very low quality of evidence), or for Parkinsonism (tremor) at medium term (1 RCT n = 25, RR 1 CI 0.2 to 4.95, very low quality of evidence). No data were reported for quality of life at medium term.Of the 26 studies comparing pimozide versus any antipsychotic, seven studies provided data for global state relapse at medium term, for which no difference was noted (7 RCTs n = 227, RR 0.82 CI 0.57 to 1.17, moderate quality of evidence). Data from one study demonstrated no difference in mental state (no improvement) at medium term (1 RCT n = 23, RR 1.09 CI 0.08 to 15.41, very low quality evidence); another study demonstrated no difference in the presence of first-rank symptoms at medium term (1 RCT n = 44, RR 0.53 CI 0.25 to 1.11, low quality of evidence). Data for extrapyramidal symptoms demonstrate no difference between groups for Parkinsonism (rigidity) at short term (6 RCTs n = 186, RR 1.21 CI 0.71 to 2.05,low quality of evidence) or medium term (5 RCTs n = 219, RR 1.12 CI 0.24 to 5.25,low quality of evidence), or for Parkinsonism (tremor) at medium term (4 RCTs n = 174, RR 1.46 CI 0.68 to 3.11, very low quality of evidence). No data were reported for quality of life at medium term.In the one study that compared pimozide plus any antipsychotic versus the same antipsychotic, significantly fewer relapses were noted in the augmented pimozide group at medium term (1 RCT n = 69, RR 0.28 CI 0.15 to 0.50, low quality evidence). No data were reported for mental state outcomes or for extrapyramidal symptoms (EPS). Data were skewed for quality of life scores, which were not included in the meta-analysis but were presented separately.Two studies compared pimozide plus any antipsychotics versus antipsychotic plus placebo; neither study reported data for outcomes of interest, apart from Parkinsonism at medium term and quality of life using the Specific Level of Functioning scale (SLOF); however, data were skewed.Only one study compared pimozide plus any antipsychotic versus antipsychotics plus antipsychotic; no data were reported for global state and mental state outcomes of interest. Data were provided for Parkinsonism (rigidity and tremor) using the Extrapyramidal Symptom Rating Scale (ESRS); however, these data were skewed.

AUTHORS' CONCLUSIONS: Although shortcomings in the data are evident, enough overall consistency over different outcomes and time scales is present to confirm that pimozide is a drug with efficacy similar to that of other, more commonly used antipsychotic drugs such as chlorpromazine for people with schizophrenia. No data support or refute its use for those with delusional disorder.