177 - Implementation of Pharmacist-Driven Penicillin Allergy Evaluation and Testing with a Focus on Bypassing Penicillin Skin Testing at an Academic Medical Center

Background: Penicillin allergies are reported by approximately 10% of the US population; however, studies reveal that >90% of those patients can tolerate penicillins.  Penicillin allergies are associated with negative health outcomes, both clinical and financial, due to reduced efficacy and increased adverse effects of alternative antibiotics.  Patient interview, penicillin skin testing (PST) and/or an oral graded challenge can be used to evaluate penicillin allergies. Different facilities use various algorithms for testing. The objective of this project was to determine whether a pharmacist-driven penicillin allergy evaluation and testing protocol which largely bypasses PST could safely de-label patients.

Methods: Adult patients (≥18 years) admitted with a penicillin allergy were evaluated for eligibility between September 2019 and June 2020.  Pregnant patients, critically-ill patients, and patients receiving test-invalidating medication were excluded.  Patients were evaluated and tested using institutional protocols, which allowed for the majority of patients to be challenged without PST.  Allergies were removed with standardized documentation, and patients were given a pamphlet and counseled to discourage relabeling.  Data collected included but were not limited to, the number of patients challenged and de-labeled, number of patients who were relabeled, and number of patients whose change in allergy status resulted in change of therapy.

Results: Forty-eight patients were interviewed and evaluated.  One patient was evaluated by PST and oral graded challenge while 27 patients underwent an oral graded challenge only.  Twenty patients were de-labeled as a result of patient interview.  One patient failed oral challenge with minor itching that did not require any treatment, while 27 patients passed. Forty-seven allergies were removed or modified. Two patients who were de-labeled were relabeled with no record of a new reaction.  Of de-labeled patients, 50% received a penicillin following removal of the allergy.

Conclusion: Penicillin allergies can be evaluated and removed using a pharmacy-driven algorithm that prioritizes direct challenges when appropriate.  Risks of a reaction are low, and removal leads to change in treatment in a significant portion of patients.