BACKGROUND: Cefazolin is the most common first-line antibiotic to prevent surgical-site infections. Patients with penicillin allergy labels often receive alternative antibiotics, which is associated with increased rates of surgical-site infections, multi-drug-resistant infections, and cost. OBJECTIVE: We sought to determine whether a hospital-wide guideline recommending first-line surgical prophylaxis in patients with penicillin allergy labels can increase the use of cefazolin without compromising safety. METHODS: We conducted a retrospective cohort study of adult surgical patients with penicillin allergy labels. The main intervention was updated hospital-wide surgical guidelines recommending first-line prophylaxis in most patients with penicillin allergy labels. We compared the preintervention and postintervention groups. The primary outcome was cefazolin use. Secondary perioperative outcomes included alternative antibiotic use and severe allergic episodes (anaphylaxis). RESULTS: The total sample comprised 7187 patients with penicillin allergy labels who underwent 8945 surgical encounters (median age [interquartile range], 61 [46-71] years)
4891 [68%] female). Cefazolin was used in 2256 (73%) patients in the preintervention group and 3390 (83%) patients in the postintervention group ( CONCLUSIONS: A hospital-wide guideline can improve use of cefazolin in surgical patients with penicillin allergy labels without increasing the risk for severe allergic reactions. National and international guidance should be considered to enhance administration of cefazolin in surgical patients with penicillin allergy labels.