Antidepressant prescribing patterns and adverse events following introduction of a National Prescribing Indicator to monitor dosulepin usage in Wales

Abstract

Aims: Limiting use of the antidepressant dosulepin has been encouraged due to associated risks of toxicity. In April 2011, the All Wales Medicines Strategy Group introduced a National Prescribing Indicator (NPI) to monitor dosulepin usage. The aim of this study was to investigate antidepressant prescribing patterns, and selected adverse events in patients prescribed dosulepin following introduction of the NPI.

Methods: An e-cohort study was conducted. Adult patients receiving regular dosulepin prescriptions between October 2010 and March 2011 were included. Characteristics of patients who were continued on dosulepin, were switched to an alternative antidepressant or whose dosulepin was discontinued following introduction of the NPI were compared.

Results: In total, 4121 patients were included. Of these, 1947 (47%) continued dosulepin, 1487 (36%) were switched and 692 (17%) discontinued. Of the 692 who discontinued, 92% did not receive a prescription for another antidepressant during the follow-up period. Patients whose dosulepin was discontinued were older and were less commonly coprescribed benzodiazepines. During follow-up, recorded incidence of selected adverse events was low across all groups and no significant difference was observed.

Conclusion: Over half of patients had discontinued dosulepin at the end of the period when the NPI was in place. Further interventions may have been required to have a greater impact on prescribing. This study provides some reassurance that dosulepin discontinuation can be a successful strategy, and that the risk of the adverse events investigated was unlikely to have been greater in those who had dosulepin discontinued than in those in whom dosulepin had been continued.

Keywords: adverse event; antidepressant; dosulepin; prescribing.