Assessment of Intravenous versus Oral Antimicrobials in a Large Regional Health Authority.

Background: Many antimicrobials given by the intravenous (IV) route have oral (PO) formulations with high oral bioavailability. The advantages of using the PO rather than the IV formulation include lower risk of adverse reactions, shorter length of hospital stay, and lower health care costs. Objectives: The primary objective was to determine the proportions of patients who received the IV and PO formulations of antimicrobials with high oral bioavailability. The secondary objectives were to determine the proportion of patients who were eligible to receive PO antimicrobials from the start of treatment, the proportion who qualified for IV-to-PO step-down, and areas of improvement to increase use of PO antimicrobials. Methods: A retrospective chart review was conducted in hospitals in the Fraser Health Authority, British Columbia, between October 18, 2019, and March 5, 2020. Two hundred charts were randomly selected for patients who had received either azithromycin, ciprofloxacin, clindamycin, fluconazole, levofloxacin, linezolid, moxifloxacin, metronidazole, sulfamethoxazole-trimethoprim, or voriconazole. Results: Of the 200 patients, 124 (62.0%) received the PO formulations, while 76 (38.0%) received the IV formulations. Of the 76 patients receiving IV antimicrobials, 39 (51.3%; 95% confidence interval 44.7%-57.9%) were eligible to receive PO antimicrobials from the start of treatment or could have been stepped down from IV to PO administration. Conclusions: More than half of patients who received IV therapy were eligible to receive the PO formulation of antimicrobials known to have high oral bioavailability; relative to earlier studies, this proportion has not improved over time. This finding highlights the need for continued vigilance in encouraging the use of PO rather than IV formulations for hospitalized patients.