Inappropriate Use of Aztreonam.

Background: Aztreonam is not a preferred empiric antibiotic because of variable susceptibilities compared with alternative agents. In addition, it has no Gram-positive activity, necessitating coadministration with vancomycin when used empirically, and is more costly when compared with other Gram-negative active agents. Aztreonam is often given to patients with a reported penicillin allergy without further investigation into the reaction or other relevant allergy information.

Study Question: How frequently is aztreonam being used inappropriately?

Study Design: We conducted a retrospective chart review at an academic medical center to assess the appropriateness of our aztreonam use.

Measures And Outcomes: Our primary outcome was frequency of appropriate aztreonam use, based on a true IgE-mediated allergy reported for each patient. We evaluated whether the patients had tolerated a beta-lactam in the past, and what the reported allergic reaction was.

Results: We included 165 patients and found that 46.7% of our aztreonam use was inappropriate, based on previous use of a beta-lactam, or no documentation of an IgE-mediated response. Of the patients with a documented beta-lactam allergy, 63 (38.2%) patients had no allergy manifestation listed, and 37 (22.4%) patients had a non-IgE-mediated allergy manifestation. Of the total population, 61 (37%) patients had tolerated a beta-lactam in the past.

Conclusions: Aztreonam should be avoided, except in the case of a true IgE-mediated allergic reaction. Our goal was to reduce the inappropriate use of aztreonam at our institution by one or more of the following: educating providers, reviewing aztreonam orders, requiring answering of order questions, or requiring an indication for use. Penicillin skin testing and desensitization are options as well.