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Dunking on Overuse of Alternative Antibiotics in Patient-Reported β-lactam Allergies

June 22, 2021

Written by Andy Hogan

Spoon Feed
A standardized process for investigating patient-reported β-lactam allergies together with a side-chain cross-reactivity chart led to significantly increased use of structurally dissimilar β-lactams for surgical prophylaxis instead of alternate antibiotic classes.

Why does this matter?
The lay public has a poor understanding of the difference between medication intolerance (eg, nausea) and true IgE-mediated hypersensitivity reactions (eg, anaphylaxis). Still, poorly defined penicillin “allergies” frequently find their way into patient charts. In the ED, these patients frequently receive alternate classes of antibiotics (often broader spectrum, with less favorable adverse effect profiles) despite existing literature showing that cross-reactivity between dissimilar β-lactams for patient-reported allergies is low (<1%). This study offers some support for increased use of dissimilar β-lactams in such situations.

Study CROSSES OVER, POSTERIZES patient-reported penicillin allergy!!!
This single-center, retrospective, before-and-after study found that implementing formalized allergy history-taking and use of a cross-reactivity chart (Figure below) for β-lactams led to significantly increased use of structurally dissimilar β-lactams instead of alternative classes (15.1% vs. 84.9%, p<0.01). Barring confirmed Type II-IV hypersensitivity reactions (eg, serum sickness to Stevens-Johnson), safe alternative agents were available for all common β-lactams. Although the study was not powered to detect a difference in rate of adverse reactions (from intolerance to true allergy), no significant difference was found between the ‘before’ and ‘after’ groups (6/1111 vs. 3/1089, respectively; p=0.323), and the overall rate of reactions was quite low. Notably, >98% of patients in the β-‘after’ group received cefazolin as alternate β-lactam therapy. Compared to the pre-operative setting, this first-generation, IV-only cephalosporin is not practical for many undifferentiated ED patients who require broader-spectrum coverage or oral agents on discharge. Nevertheless, the authors’ evidence-based cross-reactivity chart might be a useful reference for your next QI initiative or “pen allergic” patient.

From cited article supplement

Another Spoonful
For the visual learners in the group, check out the figures in this recent publication by Khan, et al.

Impact of an Antibiotic Side-Chain-Based Cross-reactivity Chart Combined With Enhanced Allergy Assessment Processes for Surgical Prophylaxis Antimicrobials in Patients With β-Lactam Allergies. Clin Infect Dis. 2021;72(8):1404-1412. doi:10.1093/cid/ciaa232.

What are your thoughts?