Clinical pharmacist-led implementation of an intravenous-to-oral antimicrobial switch protocol: A prospective...

In antimicrobial therapy, early intravenous-to-oral switch (IVOS) is recommended for eligible patients to minimize complications and optimize pharmacoeconomic outcomes. This study aimed to evaluate the impact of a clinical pharmacist-led multimodal intervention strategy on IVOS rates.

A prospective before-and-after study was conducted between January and June 2024, including observation and intervention periods. Hospitalized adults receiving IV antimicrobials were included. A two-round expert panel was convened prior to data collection to identify the criteria for IVOS. During the observation period, IV antimicrobial utilization patterns were monitored without intervention. The intervention period involved the implementation of a standardized IVOS protocol, targeted education for infectious disease physicians, and switch recommendations for eligible treatments. The primary endpoint was the difference in IVOS rates between study periods among eligible treatments.

Among 962 IV antimicrobial courses evaluated, 213 (22.1%) met the eligibility criteria for IVOS. Among patients who met IVOS eligibility criteria, the proportion undergoing overall IVOS increased from 29.0% in the observation period to 54.0% in the intervention period (p < 0.001). Among 113 IVOS-eligible cases, pharmacists recommended switching in 57 (50.4%), with a 59.6% physician acceptance rate (34/57). No significant differences were observed between periods for: microbiological cure rates, Clostridioides difficile infection incidence, intensive care unit admission rates, antimicrobial reinitiation within 48 h of treatment cessation, 15- and 30-day readmission and mortality rates. Antimicrobial costs decreased significantly from $15,600.30 (all-parenteral baseline) and $14,997.40 (adjusted baseline) to $8333.81 post intervention.

The intervention was associated with a substantial increase in overall IVOS among eligible patients, supporting its effectiveness in promoting timely de-escalation from intravenous therapy. Clinical pharmacist-led initiatives optimize appropriate switching and antimicrobial utilization in stewardship.