Inappropriate use of antimicrobials is directly associated with increased microbial resistance, longer hospital stays, higher healthcare costs, and greater patient risk. Given this scenario, this study aimed to evaluate the impact of antimicrobial rationalization on patient safety and the reduction of microbial resistance in a tertiary hospital through a systematic prescription review program.

This was an observational and retrospective study analyzing data from January 2019 to December 2024. The actions consisted of daily evaluations of prescriptions containing antimicrobials, with direct discussions with care teams regarding escalation, de-escalation, continuation, or discontinuation of antimicrobial regimens. Compliance with recommendations was later verified. Microbiological data were also analyzed to correlate rational antimicrobial use with changes in bacterial resistance patterns.

During the study period, there was a 25% increase in daily prescription evaluations. A global 26% reduction in antimicrobial use was observed. Regarding bacterial resistance, significant reductions were noted: 60% in carbapenem resistance, 18% in methicillin-resistant Staphylococcus aureus (MRSA), and 28% in ESBL-producing Enterobacteriaceae. These results indicate a positive correlation between the interventions and improved pathogen susceptibility profiles.

Rationalizing antimicrobial use proved to be an effective strategy for reducing microbial resistance and improving patient safety. Daily interactions with care teams contributed to more appropriate therapeutic decisions, directly reducing antimicrobial consumption and controlling multidrug-resistant strains. Strengthening stewardship programs should be a priority in healthcare institutions.