Implementation of a Pharmacist-led Outpatient Penicillin Allergy Testing Clinic.

Abstract

Background: Penicillin allergies affect approximately 10% of the population, leading to increased healthcare costs, treatment failures, and multidrug resistant organisms.

Objective: To determine the feasibility of implementing a pharmacist-led outpatient penicillin allergy testing program.

Methods: This single-site, retrospective cohort study was conducted from July 2022 through December 2023. The study site consisted of an outpatient clinic within a non-academic community hospital. The primary outcome was the percentage of patients who had their penicillin allergy de-labeled. Secondary outcomes included percentage of patients who received appropriate antibiotics following allergy de-labeling, incidence and type of IgE mediated penicillin reactions, number of patients who were relabeled with a penicillin allergy, number of orthopedic patients with a post-operative surgical site infection, average reimbursement per patient, and average appointment time.

Results: A total of 457 outpatients received penicillin allergy testing during the study period. Physician specialties who referred patients were orthopedics, obstetrician-gynecologists, infectious disease, urology, urogynecology, cardiothoracic surgeons, and primary care providers. For the primary outcome, 439 patients (96%) were successfully de-labeled. All de-labeled patients received appropriate antibiotics following testing. There were 17 patients who developed minor itching with or without a localized rash following the amoxicillin, and one patient had a delayed reaction of rash 12 hours after the amoxicillin that resolved with an antihistamine. One patient had their penicillin allergy re-labeled. Of the 192 orthopedic patients, 0 patients had a post-operative surgical site infection. The average reimbursement was $423 per patient with the average appointment lasting 96 minutes.

Conclusion: Pharmacists, in collaboration with multiple physician specialties, successfully implemented an outpatient penicillin allergy testing service to safely de-label patients and support antimicrobial stewardship.