Antipsychotic polypharmacy is defined as the co-prescription of more than one antipsychotic for a single patient. The practice has been criticised because of a lack of convincing evidence for its effectiveness and safety. It is associated with increased hospitalisation rates, more adverse effects, elevated cost, pharmacokinetic interactions, reduced adherence and increased mortality.

This study aimed to identify patients attending a community psychiatric service who are currently prescribed more than one antipsychotic. It aimed to examine their diagnoses, comorbid physical illnesses and other medications. Patterns of co-prescription were also considered.

A computerised database was utilised to identify all patients prescribed any antipsychotic.

98 patients who were prescribed antipsychotics were identified. Of these, 22 (22%) were prescribed two antipsychotics. No pattern of a preferred combination of antipsychotics was identified. 15 of those prescribed more than one antipsychotic (68%) were prescribed two second generation drugs, with the remainder on a combination of a first and second generation antipsychotic.

Antipsychotic polypharmacy rates (22%) were in line with the European average (23%). Antipsychotic polypharmacy should be a last resort after evidence-based treatments have tried and failed. It is recommended that it is considered only after a minimum of two trials of single antipsychotics at adequate doses and durations; after at least one trial of depot antipsychotic; and following at least one trial of Clozapine, with consideration given to ECT. Focused interventions rather than passive dissemination of guidelines are more likely to reduce antipsychotic polypharmacy rates.