Background and importance Pain therapy in inpatients is regularly suboptimal and might be improved by clinical pharmacy services with the aim of optimising pain control and reducing iatrogenic harm related to adverse drug events and overuse. In our hospital, we have implemented a software supported check of medication appropriateness (CMA), which is a centralised pharmacist led service consisting of a clinical rule based screening for potentially inappropriate prescriptions (PIPs) and a subsequent medication review by pharmacists.

Aim and objectives We aimed to investigate the impact of the CMA on pain related prescribing.

Material and methods A quasi-experimental study was performed in a 1995 bed tertiary hospital, using an interrupted time series design. Pre-implementation, patients were exposed to standard of care. Afterwards, a pain focused CMA comprising 12 clinical rules pertaining to analgesic prescribing were implemented in the post-implementation period. A regression model was used to assess the impact of the intervention on the number of pain related residual PIPs. For the pre-implementation period, data collection was performed retrospectively (January 2016 to December 2018). Post-implementation (January 2019 to July 2020), an initial PIP was identified prospectively in the CMA. The total number of recommendations and acceptance rate were recorded for the post-implementation period.

Results At baseline, the median proportion of residual PIPs was 69.0% (range 50.0–83.3%) with a median number of 13.1 (range 9.5–15.8) residual PIPs per day. After the CMA intervention, the median proportion and median number decreased to 11.8% (range 0–50%) and 2.2 (range 0–9.5), respectively. Clinical rules showed an immediate relative reduction of 66% (p<0.0001) in pain related residual PIPs. A significant decreasing time trend was observed during the post-implementation period. Over 1 year in the post-implementation period, the clinical pharmacists provided 1683 recommendations for 1427 individual patients during 1478 hospital admissions. The treating physicians accepted 74.3% of the recommendations.

Conclusion and relevance We proved that the CMA approach improved analgesic prescribing, as the number of pain related residual PIPs was reduced in a highly significant and sustained manner. The downward trend in the post-implementation period might indicate a learning effect on physicians, resulting in a higher acceptance rate of recommendations over time. More pharmacist involvement and the use of clinical rules during hospital stay should be further promoted to optimise appropriate prescribing of analgesics.

Conflict of interest No conflict of interest