Implementation and Impact of a β-Lactam Allergy Assessment Protocol in a Veteran Population

Approximately 10% of the US population reports having a β-lactam allergy, although nearly 90% do not have a true immunoglobulin E (IgE)-mediated reaction. This misconception results in using nonpreferred antibiotics, leading to antimicrobial resistance and treatment failure. To evaluate, clarify, and clear β-lactam allergies, we implemented a pharmacist-driven β-lactam allergy assessment (BLAA) protocol and penicillin allergy clinic (PAC). The purpose of this study was to illustrate the BLAA process, including the pharmacist-run PAC, and assess the impact on allergy clearance.

Clinical pharmacy specialists (CPS) evaluated hospitalized veterans with β-lactam allergies, using the BLAA protocol. Eligible patients could later be seen in PAC. This was a retrospective observational review of the BLAA protocol to assess recommendations for β-lactam antibiotic use and PAC outcomes.

Between November 2017 and February 2020, 278 patients were evaluated, and 32 were seen in the clinic. The most common allergen was penicillin, and the most reported reaction was a rash (27%) or pruritus and urticaria (18%). Through PAC and the BLAA protocol, 86 patients (31%) were cleared for allergy removal, and 188 (68%) were cleared for alternative β-lactams. The evaluation revealed that 274 patients (99%) were eligible to receive a β-lactam antibiotic, and only 4 patients (1%) were recommended for avoidance of all β-lactams.

These findings highlight the utility of the pharmacist-driven BLAA protocol. We illustrated that most patients with documented β-lactam allergies were eligible for alternative β-lactams. The implementation of the BLAA protocol and pharmacist-run PAC facilitated allergy clearance and has the potential to promote alternative β-lactam use.