The purpose of this study is to assess cross-reactivity and tolerability of ertapenem in patients with IgE-mediated allergy to at least one beta-lactam molecule.

Ertapenem is a new carbapenem, stable to dehydropeptidase which has a broad antibacterial activity. Ertapenem exhibits a bactericidal mode of action and it has a long half-life of 4.5 hours; for this reason it can be developed as a single daily dose carbapenem.

In literature, no cases of IgE-mediated allergy to ertapenem have been described until now. However, a single study put in evidence a 47% rate of cross-reactivity between imipenem-cilastatin and beta-lactams in a group of patients affected by IgE-mediated allergy to these drugs. For this reason carbapenem administration to beta-lactam allergic patients has always been considered potentially harmful. Other studies reported lower cross-reactivity rates (from 7 to 11%) between imipenem-cilastatin and beta-lactams but patients of these studies did not undergo any allergy testing in order to demonstrate the pathogenesis of the reactions.

Recent studies put in evidence that imipenem has a very low cross-reactivity rate with other beta-lactams and they have a very good tolerability among patients with IgE-mediated allergy to beta-lactams: Romano et al. found a cross-reactivity rate of 0.9% between imipenem and penicillins in 112 penicillin-allergic patients (mean age 44.56 ± 15.66 ys.); Atanasković-Marković et al. found a cross-reactivity rate of 0.8% in 124 paediatric patients (age range 3-14 ys.) between imipenem and penicillins. In both groups imipenem was well tolerated by patients with negative allergy testing.

Meropenem showed to have a good tolerability too in penicillin allergic patients: Romano et al. found a cross-reactivity rate of 0.9% between penicillins and meropenem in penicillin-allergic patients (mean age 47.83 ± 15.8); Atanasković-Marković et al. found a cross-reactivity rate of 0.8% in 109 paediatric patients (age range 3-14 ys.) between meropenem and penicillins. In both groups meropenem was well tolerated by patients with negative allergy testing.

No data regarding the cross-reactivity of ertapenem with other beta-lactams and its tolerability among patients with IgE-mediated allergy beta-lactams are available in literature.

Aim of the study On the basis of those data, we decided to investigate the cross-reactivity of ertapenem with other beta-lactams in patients suffering from IgE-mediated allergy to at least one beta-lactam molecule and its tolerability in a group of a patients with negative allergy testing with ertapenem.

Inclusion Criteria:

• IgE-mediated allergy to at least one beta-lactam molecule

Exclusion Criteria:

• positive allergy testing to ertapenem
• chronic diseases
• treatment with beta-blockers
• pregnancy