Aztreonam cross-reactivity

Q: Aztreonam may have cross-reactivity with which of the cephalosporins? (select one)

A) ceftazidime

B) cefazolin

C) cefuroxime

D) cefepime

E) ceftriaxone

Answer: A

Interestingly Aztreonam, a monobactam that can be safely used in patients allergic to penicillin, may have cross-reactivity with ceftazidime. Most patients tolerate aztreonam with ceftazidime allergy, but concern stays for patients with previous immediate reactions to ceftazidime. The chance of developing a reaction due to cross-reactivity is about five percent. An alternate antibiotic should be used, or aztreonam skin test should be performed.

#pharmacology

References:

1. Pérez Pimiento A, Gómez Martínez M, Mínguez Mena A, et al. Aztreonam and ceftazidime: evidence of in vivo cross allergenicity. Allergy 1998; 53:624.

2. Iglesias Cadarso A, Sáez Jiménez SA, Vidal Pan C, Rodriguez Mosquera M. Aztreonam-induced anaphylaxis. Lancet 1990; 336:746.

3. van der Poorten MM, Van Gasse AL, Hagendorens MM, et al. Nonirritating skin test concentrations for ceftazidime and aztreonam in patients with a documented beta-lactam allergy. J Allergy Clin Immunol Pract 2021; 9:585.