2026 Southeastern Residency Conference

Inpatient Pharmacist-led Penicillin Allergy Delabeling (iPPADL)
Authors: Caleb Gosnell, Benjamin Britt, Vince Buttrick, Erik Turgeon at Lexington Medical Center
Background/Purpose: Reports of penicillin allergies are common, as many as 25% of patients have a penicillin allergy in their medical record. Most of these patients have mild reactions, such as urticaria. Patients with a remote history of allergy from childhood are <5% likely to have a retained allergy to penicillins. Recent studies have identified pharmacist-led allergy de-labeling approaches with a focus on antimicrobial stewardship have positive outcomes on alternative antibiotic utilization, Clostridioides difficile infection rates, inpatient length of stay, and patient costs. Barriers to traditional approaches include the need for either skin testing supplies with appropriate training or additional stock of oral amoxicillin. In a cost-saving approach, it may be efficacious to use patient medical history and interviewing to assess the possibility of de-labeling.
Methodology: This was a pre- and post-intervention review of inpatient encounters at a single-center 607-bed community teaching hospital. The intervention for this study was the implementation of a pharmacist-led penicillin allergy delabeling protocol. Pharmacists determine eligibility by reviewing PEN-FAST assessment results, reported allergy reactions, and previous inpatient penicillin/aminopenicillin administrations. Patients with a PEN-FAST score of 0 with a non-immune mediated reaction, such as nausea, qualified for de-labeling.  Patients with a PEN-FAST score of 0 or 1, with a minor immune-mediated reaction, such as urticaria, were further evaluated for prior inpatient administrations of a penicillin or aminopenicillin. If tolerated, the patient qualified for delabeling. All patients received bedside education of the process of qualifying for delabeling and required verbal consent to remove the allergy from the medical chart.  The pre-intervention group consisted of inpatients with a penicillin allergy and PEN-FAST assessment between July 1, 2025 – October 31, 2025. The post-intervention group consisted of inpatients with a penicillin allergy and PEN-FAST assessment between November 1, 2025 – February 28, 2026. Outcomes were then assessed manually by the investigator through electronic health record (EHR )-generated data and manual chart review.
Results: During the pre-intervention phase, a total of 1,912 admissions had a labeled penicillin allergy and 215 had a PEN-FAST score reported with 75 patients eligible for delabeling. In the post-intervention phase, a total of 1,527 admissions had a penicillin allergy. Of those admissions, 232 had a PEN-FAST score reported. Seventy-nine patients were eligible for delabeling with 25 qualifying by a non-immune reaction and 54 with a penicillin class administration. Piperacillin/tazobactam was the major contributor with 38 eligibilities. A total of 18 patients were delabeled with most (14) qualifying via penicillin class administrations. Three patients refused the intervention, and two patients were relabeled at a subsequent outpatient encounter.
Conclusions: A pharmacist-led allergy delabeling protocol based upon chart review and patient interview is a low-cost alternative to skin testing, though its success is highly limited by workflow time constraints, altered patient mentation, EHR reporting logistics, and patients located on floors without decentralized pharmacists. Another potential limiting factor is that this study did not account for patients with short length of stays that could further decrease the time available for assessment and intervention. Future considerations are a more direct identification process through pharmacist notification rather than a passive report that must be actively reviewed. Additionally, expanding the protocol to include conversations with medical decision-makers for patients with chronic altered mental status. In the future, the protocol will shift to a stewardship initiative to capture more patients, improve decentralized communication of opportunities, and potential expansion to oral challenge in patients who are low risk for a true allergy without qualifying administrations.