Pimozide
| Evidence Level: L4 | Predicted Indications: 10 |
Table of Contents
Pimozide: From Schizophrenia/Tourette Syndrome to Trichotillomania
One-Sentence Summary
Pimozide is a diphenylbutylpiperidine-class antipsychotic historically used for schizophrenia and Gilles de la Tourette syndrome. The TxGNN model predicts it may be effective for Trichotillomania (compulsive hair-pulling disorder), with no registered clinical trials and 10 supporting publications — mostly reviews and case reports — currently available for this specific indication.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Schizophrenia and Gilles de la Tourette syndrome (per supporting literature; not specified in the supplied regulatory dataset) |
| Predicted New Indication | Trichotillomania |
| TxGNN Prediction Score | 99.996% |
| Evidence Level | L4 |
| UK Market Status | Not Marketed |
| Number of Marketing Authorisations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data for pimozide is not available in this evidence pack. Based on the supporting literature and repurposing rationale, pimozide is a selective dopamine D2 receptor antagonist. This central D2-blocking action underlies its established antipsychotic effect and its efficacy in Tourette syndrome (tic suppression).
The proposed link to trichotillomania is not a direct pharmacological match to the original indication, but rather an extrapolation from the obsessive-compulsive disorder (OCD) “augmentation” literature: trichotillomania sits within the OCD-spectrum of disorders, and low-dose pimozide has historically been used as an add-on to serotonin reuptake inhibitors (SSRIs/SRIs) in SRI-refractory OCD-spectrum presentations, including hair-pulling behaviour. Several of the supporting papers (e.g. PMID 1532960, PMID 10357517) describe this augmentation strategy rather than pimozide monotherapy for trichotillomania specifically.
Mechanistically, this is a reasonable hypothesis given the D2-antagonist augmentation precedent in related compulsive-spectrum conditions, but it remains an indirect, class-based rationale rather than evidence generated specifically for trichotillomania. No modern (post-1990s) prospective trials support this use, and current trichotillomania management (e.g. N-acetylcysteine, habit-reversal therapy) has largely moved away from typical antipsychotics.
Clinical Trial Evidence
Currently no related clinical trials registered
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 30446201 | 2018 | Review | Clinics in Dermatology | Overview of antipsychotic drugs (including pimozide) in dermatology via central and peripheral receptor effects |
| 27320510 | 2016 | Review | Tijdschrift voor Psychiatrie | Review of paediatric trichotillomania treatment options; notes limited pharmacotherapy research |
| 15554735 | 2004 | Review | American Journal of Clinical Dermatology | Comprehensive review of pimozide in dermatologic/psychodermatologic practice, incl. off-label uses |
| 36802832 | 2023 | Evidence mapping (RCTs) | Journal of Cutaneous Medicine and Surgery | Systematic appraisal of RCTs for pharmacological management of primary psychodermatologic disorders |
| 28225970 | 2017 | Case report | Anais Brasileiros de Dermatologia | Case report of trichotillomania with dermatoscopic differential diagnosis vs alopecia areata |
| 1532960 | 1992 | Case series (open-label augmentation) | The Journal of Clinical Psychiatry | Low-dose pimozide as augmentation to SSRIs in trichotillomania; explores overlap with OCD/Tourette syndrome |
| 11475941 | 2001 | Review | CNS Drugs | Review of psychogenic excoriation (related compulsive skin-picking condition), diagnostic criteria and treatment approaches |
| 10497682 | 1999 | Review | Annals of the Academy of Medicine, Singapore | Review of trichotillomania as an under-diagnosed psychiatric syndrome |
| 10900563 | 2000 | Clinical profile | International Journal of Psychiatry in Medicine | Clinical profile of delusional parasitosis (related monosymptomatic psychosis treated with pimozide) |
| 10357517 | 1999 | Case series | Journal of Child and Adolescent Psychopharmacology | Open-label low-dose pimozide (and risperidone) addition in SRI-refractory trichotillomania (3 cases) |
UK Market Information
Pimozide is currently not marketed in the UK, and no marketing authorisations are recorded in this dataset (0 licenses on record). Prescribers and reviewers should verify current UK licensing status directly via the MHRA product database, as historical pimozide products (e.g. Orap) may no longer hold active UK authorisation.
Safety Considerations
Please refer to the SmPC and BNF for safety information. Report suspected adverse reactions via the Yellow Card Scheme.
Note: Key warnings, contraindications, and drug-drug interaction data for pimozide were not available in this evidence pack (flagged as a Blocking data gap — see Conclusion below). Pimozide is a first-generation antipsychotic and, as a class, warrants careful review of cardiac and CNS safety information before any off-label use is considered.
Conclusion and Next Steps
Decision: Hold
Rationale: The predicted indication (trichotillomania) is supported only by L4-level evidence — case reports, reviews, and mechanistic extrapolation from OCD-augmentation literature — with no registered clinical trials specific to trichotillomania. Critically, key safety data (SmPC warnings, contraindications) required for even a preliminary safety assessment are missing from this evidence pack, which is a blocking gap for progression.
To proceed, the following is needed:
- Full SmPC/prescribing information (warnings, precautions, contraindications) for pimozide — currently a Blocking data gap
- Detailed mechanism of action (MOA) data from DrugBank or equivalent source
- A dedicated clinical trial or systematic review specifically evaluating pimozide (or SSRI-augmentation with pimozide) in trichotillomania
- Confirmation of current UK marketing/licensing status, since the drug is presently not marketed in the UK
- A structured cardiac and CNS safety monitoring plan, to be finalised once full SmPC data is available
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.