Cross-reactivity and tolerability of ertapenem in patients with IgE-mediated hypersensitivity to β-lactams

Background and objective: administration of carbapenems to β-lactam-allergic patients has always been considered potentially harmful because of a 47.4% rate of cross-reactivity to imipenem reported in a single study. nevertheless,recent studies have shown that the rate of cross-reactivity of imipenem and meropenem with penicillins is lower than 1%. the aim of this study was to evaluate the possibility of using ertapenem in patients with an established ige-mediated β-lactam allergy. patients and methods: we studied all participants who came to our allergy unit and had a clinical history of immediate hypersensitivity reactions to β-lactams. the inclusion criteria were a positive skin test result to at least 1 β-lactam molecule and/or positive specific ige (when available). all participants underwent immediate-type skin tests with several β-lactam molecules including ertapenem. challenges with intravenous ertapenem were performed on 2 different days in patients with negative skin test results. results: we examined 49 patients with a clinical history of immediate reactions to β-lactams. all the patients had positive skin tests and/or positive specific ige to at least 1 β-lactam reagent and negative carbapenem skin tests. thirty-six patients agreed to undergo the challenges and 35 tolerated the full dose of ertapenem. conclusions: the practice of avoiding carbapenems in patients with β-lactam allergy should be abandoned considering the very low rate of cross-reactivity. β-lactam-allergic patients who need ertapenem therapy should undergo skin tests and,if negative,a graded challenge to assess tolerability. © 2016 esmon publicidad.