The Safety of Aztreonam Versus Ceftazidime in Patients Labeled With Penicillin Allergy: A Cohort Study.

Purpose: Penicillin allergy is the most common drug allergy among hospitalized patients. Traditionally, aztreonam is recommended for patients labeled with penicillin allergy (PLWPA) in our institutional empirical antibiotic guidelines. Due to a global aztreonam shortage in December 2022, the antimicrobial stewardship unit recommended ceftazidime as a substitute.