Background: In this study, we implemented an active intervention for patients taking carbapenems for 14 days or more at a single tertiary hospital and evaluated the effect of the intervention.
Methods: This was a quasi-experimental study comparing carbapenem use at 1-year preintervention to 1-year post-intervention. From January 2020, a pharmacist who participated in the Antibiotics Stewardship Program (ASP) monitored the weekly medical records of patients who were prescribed carbapenem for 14 days or more and notified the infectious disease specialist. The infectious disease specialist evaluated the appropriateness and recommended the termination of carbapenems via direct communication with the prescribing physician when carbapenems were inappropriately continued.
Results: Overall carbapenem consumption did not significantly differ after and before the intervention (43.0 vs. 43.5 daily defined doses (DDDs)/1,000 persons-day, P=0.630). In the interrupt time series analysis, the trend of carbapenem use did not differ before and during the intervention (P=0.732). In intervention periods, 367 patients who continued with carbapenems for more than two weeks were evaluated for appropriateness, and we intervened in 42 patients (11.4%). Carbapenem use was terminated in 40 patients (95.2%) within one week after the intervention via direct communication, whereas the remaining two patients developed infectious diseases requiring carbapenem administration within 30 days after the intervention.
Conclusion: In this study, there was no significant effect on the overall use of carbapenems since the intervention targeted only patients with long-term administration of carbapenems. However, inappropriate carbapenem use can be reduced through direct communication between infectious disease specialists and prescribing physicians, leading to high compliance reates and low infection recurrence.

Keywords: Antimicrobial stewardship program, Intervention, Carbapenem