Penicillin allergies and community antibiotic prescriptions: A secondary analysis of prescribing choices in six family medicine clinics in southern Ontario, 2018–2019

Background: While 10% of the population has a reported penicillin allergy, 90% of these allergy labels may not be accurate. However, the impact of penicillin allergy de-labelling on antibiotic use in primary care is not clear. We aimed to determine the effect of penicillin allergy labels on antibiotic use in the community for common infections. Methods: A secondary analysis of cross-sectional data from a previous stewardship intervention study in six family medicine clinics in southern Ontario was conducted. Antibiotic prescriptions to 914 adult patients presenting with common respiratory and urinary tract infections from 2018 to 2019, with and without a penicillin allergy in their electronic medical record, were examined. The primary outcome was what antibiotics were prescribed to patients with and without a penicillin allergy. Results: Of 914 patients included, 84 (9.2%) had a penicillin allergy listed in their medical record. Penicillin allergy labels affected prescribing for acute respiratory infections, with patients more commonly prescribed macrolides ( p < 0.0001), tetracyclines ( p < 0.0001), and fluoroquinolones ( p = 0.01) compared with patients without a penicillin allergy label. If all penicillin allergy patients underwent testing and were successfully de-labelled, we estimated that 40.3/914 (4.4%) of antibiotic prescriptions to adults in this study would change. Conclusions: Antibiotic prescribing choices were affected by penicillin allergy labels, with more frequent prescribing of broad-spectrum antibiotics, particularly in acute respiratory infections. However, the proportion of all antibiotic prescriptions that would be changed by penicillin de-labelling was small. Other antimicrobial stewardship approaches in addition to penicillin allergy de-labelling may be needed to reduce antibiotic overuse in primary care.