Pharmacist-driven allergy to beta-lactam evaluation in the emergency department

Penicillin (PCN) is the most common drug allergy in medical records and have been linked to suboptimal antibiotic regimens and negative externalities.

To evaluate the successful de-labeling of PCN allergies following the implementation of a pharmacist-driven PCN de-labeling protocol in an emergency department (ED) PRACTICE DESCRIPTION: VA Indiana Healthcare System (VAIHCS) is a tertiary level 1A VAMC that registers about 30,000 ED visits annually.

An Allergy to Beta-Lactam Evaluation (ABLE) VA template is available that guides pharmacists through allergy history and provides recommendations on alternative beta-lactam agents. Although a recent pharmacist-led efforts in ED has been described, literature specifically in the ED remains limited.

This study included patients who presented to the ED over a six-month period and underwent the ABLE protocol. The primary outcome was the percentage of patients whose PCN allergy was de-labeled. Secondary outcomes included the percentage of patients de-labeled within the ED versus de-labeled at follow-up, percentage of patients presenting to the ED with a PCN allergy compared to the number of patients de-labeled, and the number of patients who received beta-lactam antibiotics immediately following pharmacist assessment.

From May 15, 2024, to October 31, 2024, 44 patients met inclusion criteria. A total of 64% (28/44) had their PCN allergy de-labeled. Of the 28 patients de-labeled, 75% (21/28) were de-labeled via direct oral amoxicillin challenge, and the remainder were de-labeled based on allergy history review alone. Following de-labeling, 36% (10/28) received a beta-lactam antibiotic during the same ED visit. No adverse reactions were observed. There was a 95% follow-up rate at 72 hours post amoxicillin challenge.

A pharmacist-led PCN de-labeling protocol in the ED is feasible, safe, and facilitates access to beta-lactam antibiotics for eligible patients, while highlighting practical barriers that must be addressed for broader implementation.