Nonsevere (immediate or delayed) hypersensitivity: Implications of cross-reactivity between penicillins and cephalosporins

Cephalosporins are safe to administer to patients with nonsevere (immediate or delayed) penicillin hypersensitivity.

Although cefalexin and cefaclor (often referred to as aminocephalosporins) contain similar R1 side-chains to aminopenicillins (ie amoxicillin and ampicillin), they can still be administered in patients with nonsevere (immediate or delayed) hypersensitivity to penicillin. However, because cross-reactivity between these drugs is possible, consideration should be given to the extent of the reaction, patient acceptability, and the suitability of non–beta-lactam options.