Implementation of a pharmacist-led outpatient penicillin allergy testing clinic

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

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

This single-site, retrospective cohort study was conducted from July 2022 through December 2023. The study site consisted of an outpatient clinic within a nonacademic community hospital. The primary outcome was the percentage of patients who had their penicillin allergy delabeled. Secondary outcomes included percentage of patients who received appropriate antibiotics following allergy delabeling, incidence and type of immunoglobulin E mediated penicillin reactions, number of patients who were relabeled with a penicillin allergy, number of orthopedic patients with a postoperative surgical site infection, average reimbursement per patient, and average appointment time.

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 delabeled. All delabeled patients received appropriate antibiotics following testing. There were 17 patients who developed minor itching with or without a localized rash following the amoxicillin challenge, 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 relabeled. Of the 192 orthopedic patients, 0 patients had a postoperative surgical site infection. The average reimbursement was $423 per patient with the average appointment lasting 96 minutes.

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