Bipolar disorder (BD) is associated with periodic symptoms’ exacerbations, leading to functional impairment, substance abuse, and increased risk of suicide and accidents. Clozapine has never been approved for the treatment of BD but it is used in severe episodes.

The aim of the study is to evaluate the risks and benefits of switching remitted BD patients treated with clozapine to another antipsychotic medication.

We assessed the proportion of relapsed patients after switching clozapine, time until relapse, type of relapse and the number of admissions.

This was an observational, mirror image study of 62 remitted BD outpatients treated with clozapine. Following a change in drug reimbursement rules by which clozapine was no longer reimbursable for patients with BD, 25 patients were switched to another antipsychotic and the rest of 37 continued on clozapine agreeing to pay treatment.

The mean score of CGI-BP at admission in study was in on both groups almost similar (2.3 vs. 2.4). After switching, a significant proportion of patients relapsed (77%), in 100% cases with a manic episode requiring hospitalisation. The mean YMRS score at relapse was significantly higher compared with the evaluation at the time prior to switching (31.78 (SD=9.72) vs. 11.99 (SD=7.29), P<0.01).

Despite the limitations of this naturalistic study, the results suggest that switching from clozapine to another antipsychotic may increase the risk of relapses in remitted patients with BD. The risks, costs and consequences of symptoms exacerbation should be weighed against the quest to control pharmacy costs.