Background: Studies performed on samples larger than 100 subjects with a documented IgE-mediated hypersensitivity to penicillins have demonstrated a cross-reactivity rate of approximately 1% between penicillins and both imipenem and meropenem, whereas a single study found a cross-reactivity rate of 6.2% with aztreonam in 16 such subjects.
Objective: To assess the cross-reactivity and tolerability of aztreonam and 3 carbapenems (imipenem-cilastatin, meropenem, and ertapenem) in patients with documented IgE-mediated hypersensitivity to penicillins.
Methods: A total of 212 consecutive subjects with immediate reactions to penicillins and positive results on skin tests to at least 1 penicillin reagent underwent skin tests with aztreonam and carbapenems; subjects with negative results were challenged with escalating doses of aztreonam and carbapenems.
Results: All subjects displayed negative skin test results to both aztreonam and carbapenems; 211 accepted challenges and tolerated them. Challenges were not followed by full therapeutic courses.
Conclusions: These data indicate the tolerability of both aztreonam and carbapenems in penicillin-allergic subjects. In those who especially require these alternative β-lactams, however, we recommend pretreatment skin tests, both because rare cases of cross-reactivity have been reported and because negative results indicate tolerability.
Keywords: Aztreonam; cross-reactivity; ertapenem; imipenem; meropenem; penicillin allergy; skin tests; tolerability.
Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.