Impact of psychotropic pro re nata prescription-monitoring programme on prescriptions for inpatients with psychiatric disorders: a retrospective observational study.

Background: Pro re nata (PRN) medication is used "as needed" for symptoms such as agitation and insomnia, in addition to regular daily pharmacotherapy of mental disorders. However, there is no high-quality evidence on the effectiveness of psychotropic PRN medications and concerns have been raised about their potential to contribute to polypharmacy. This study introduced a psychotropic PRN prescription-monitoring programme for psychiatric inpatients with the aim of examining the change before and after the implementation of the programme.

Method: This study included 389 patients admitted to the psychiatric department between 1 July 2021 and 30 June 2023. The psychotropic PRN prescription-monitoring programme was implemented in July 2022, and the participants were classified into monitoring and non-monitoring groups. Demographic data (age, sex, and diagnosis), regular prescriptions before admission and at discharge, psychotropic PRN prescriptions before admission and at discharge, and the total number of psychotropic PRN prescriptions during hospitalisation were compared between the two groups. Data on psychotropic prescription were collected by psychotropic category. The significance level of 5% was set at 1.67 × 10^-3 using the Bonferroni correction for multiple testing.

Results: The psychotropic PRN prescription ratio at discharge in the monitoring group was 9.3%, which was significantly lower than the 28.1% in the non-monitoring group. The percentage of patients with a PRN prescription during hospitalisation in the monitoring group was 29.8%, which was significantly lower than the 64.5% in the non-monitoring group. In the non-monitoring group, there was no statistically significant difference in the number of psychotropic drugs prescribed regularly before and after admission. However, in the monitoring group, the number of psychotropic drugs in the regular prescriptions at discharge was 1.87 ± 1.24, which was significantly lower than 2.47 ± 1.90 in the regular prescription before admission.

Conclusions: Our findings suggest that a psychotropic PRN prescription-monitoring programme may contribute to the elimination of polypharmacy, including regular prescriptions. Further research is required to optimise psychotropic PRN prescriptions and reduce polypharmacy.