EBQ:Cephalosporin Cross-reactivity
Prior to 1980, penicillins(PCN) and cephaloporins were often produced using the same fungus and the chance for contamination during the manufacturing process of a cephalosporin with a PCN was high. The allergy was assumed to be due to the beta-lactam ring but was later determined to be due to the manufacturing process.
More recent studies have determined that the actual risk of cross-reactivity relates to side chain similarity and not the beta-lactam ring. 1st and 2nd generation penicillins share the same R-1 side chain and are more likely to exhibit cross reactivity. A current review of the literature demonstrates that the 10% or greater allergy that is commonly reported may be exaggerated.
- 1st generation cephalosporins: cefadroxil, cefatrizine, cephalexin, cephradine
- 2nd generation cephalosporins: cefaclor, cefprozil
Campagna Review Article
- Overall cross-reactivity rate between cephalosporins and penicillins in patients reporting a penicillin allergy = 1%. [1]
- Overall cross-reactivity rate in patients with a confirmed penicillin allergy = 2.5%.
- Cross-reactivity between penicillins and 1st and 2nd generation cephalosporins is possible.
- Cross-reactivity between penicillins and ALL 3rd and 4th generation cephalosporins is negligible.
- If a patient has an allergy to amoxicillin or ampicillin, avoid cefadroxil, cefaclor, cefatrizine, cefprozil, cephalexin, and cephradine.
Sources
- ↑ Campagna JD, Bond MC, Schabelman E, Hayes BD. The use of cephalosporins in penicillin-allergic patients: A literature review. J Emerg Med. 2012;42(5):612-20