Penicillin Allergies

Patients with Stevens-Johnson syndrome, toxic epidermal necrosis, DRESS or allergic interstitial nephritis as a result of penicillins, although unlikely to have a cross-reaction, should receive non-cephalosporin based regimens if possible based on the lack of data in this situation.

Do not use aztreonam if patient is allergic to ceftazidime. Aztreonam shares the same side-chain as ceftazidime and thus cross-reactivity may occur.

Carbapenems are not expected to cross react if patient is allergic to penicillin or cephalosporins. Carbapenems are structurally dissimmilar to penicillins and cephalosporins and cross-reactivity is not expected when these agents are used.