Penicillin Allergy

Administration of a cephalosporin to a patient with a history of penicillin allergy

More than 99 percent of penicillin skin test-positive patients tolerate treatment with carbapenems, despite a significant rate of cross-reactivity between penicillins and carbapenems on skin testing.

An individual patient's risk of reacting to a carbapenem may be assessed based upon the results of penicillin skin testing, the clinical features of the penicillin reaction, and the time elapsed since the last reaction to penicillin. The approach is identical to that for cephalosporins.

Aztreonam is the only monobactam currently available for clinical use. There is no evidence of immunologic cross-reactivity between penicillins and monobactams, and penicillin-allergic patients may receive aztreonam normally.