The Long-term Impact of a Pharmacist-Led Antimicrobial Stewardship Penicillin Allergy Delabeling Ward Round

Abstract

Aim Inpatient penicillin allergy is associated with negative patient, microbiological and health service outcomes. We reviewed the long-term safety and antimicrobial stewardship impacts of a pharmacist-led penicillin allergy delabeling ward round. Methods Adult inpatients with a penicillin allergy label were evaluated during a pharmacist-led penicillin allergy ward round at Austin Health. Using the validated Antibiotic Allergy Assessment Tool (AAAT) and PEN-FAST decision rule, patients with a low-risk penicillin allergy or PEN-FAST score < 3, were offered a single-dose direct oral challenge (DOC). Inpatient antimicrobial prescribing was reviewed pre-allergy assessment, post-delabeling, and three months post-discharge. Results Between 21 January 2019 and 24 August 2022, 483 inpatients were reviewed. 110 (23%) patients had a non-immune mediated penicillin allergy and were directly delabeled. 170 (35%) patients received a DOC, of which 159 (94%) had no reaction, and were delabeled. No severe reactions occurred. Seven (4%) patients had a delayed onset maculopapular exanthema and four (2%) patients reported non-immune mediated reactions. During the index admission, there was increased prescribing of penicillins (OR: 26.87, 95% CI: 8.31-86.87) and decreased prescribing of restricted antimicrobials (OR: 0.49, 95% CI: 0.28-0.85) in delabeled patients, compared with patients not delabeled. At three months post-discharge, delabeled patients were more likely to be prescribed penicillin, instead of alternate antimicrobials, compared to patients who were not delabeled (OR: 15.14, 95% CI: 3.59-63.74). Conclusion We demonstrate that a pharmacist-led inpatient penicillin allergy delabeling ward round is safe, and optimises antimicrobial prescribing during inpatient admission and following discharge. Impact In hospitalised patients, a pharmacist-led penicillin allergy delabeling program is a sustainable model that enables assessment of patient penicillin allergy labels, opportunistic testing where appropriate, and better antibiotic prescribing. Improved antibiotic prescribing can minimise the complications associated with non-preferred antibiotics, prevent the development of resistant bacteria, and reduce hospital length of stay.