Drug Cross Sensitivty Reaction Part 2

Cross-reactivity of beta-lactam antibiotics

Beta-lactam antibiotics = penicillins, cephalosporins, carbapenems, and monobactams.

The safety of administering beta-lactam antibiotics to penicillin-allergic patients is highly debated and is based mainly on anecdotal information regarding the incidence of cross-reactivity.

CEPHALOSPORINS

Anne et al demonstrated a high incidence of in vitro cross-reactivity (up to 20%) between penicillins and cephalosporins. Cephalosporins involved in these reports included cephalothin and cephaloridine.

Petz et al demonstrated a 4-fold increase in the incidence of cephalosporin reactivity--including cephaloridine, cephalothin, and cephalexin--in patients allergic to penicillins (8.1%) compared with patients not allergic to penicillins (1.9%). When this incidence is compared with the overall incidence of allergic reactions to cephalosporins (4%), there is a 2-fold increase of reactivity in patients allergic to penicillins.

CARBAPENEMS

Already discussued in part 1

MONOBACTAMS

To date, aztreonam has not demonstrated clinical cross-reactivity in penicillin-allergic patients.

Ceftazidime has a side chain identical to that of aztreonam and clinical cross-reactivity has been demonstrated in vitro.

The clinical significance of this has not been studied; however, patients who are allergic to aztreonam should not be administered agents with similar side chains.

References
1. Saxon A, Beall GN, Rohr AS, Adelman DC. Immediate hypersensitivity reactions to beta-lactam antibiotics. Ann Intern Med 1987;107:204-215.
2. Neftel KA, Cerny A. Beta-lactam antibiotics other than penicillins and cephalosporins. In Dukes MNG, ed. Meyler's Side Effects of Drugs, 12th ed. Amsterdam: Elsevier, 1992:632-634.
3. Kishiyama JL, Adelman DC. The cross-reactivity and immunology of beta-lactam antibiotics. Drug Saf 1994;10:318-327.
4. Anne S, Reisman RE. Risk of administering cephalosporin antibiotics to patients with histories of penicillin allergy. Ann Allergy Asthma Immunol 1995;74:167-170.
5. Petz LD. Immunologic cross-reactivity between penicillins and cephalosporins: a review. J Infect Dis 1978;137(Suppl):S74-S79.
6. Preston SL, Briceland LL, Lesar TS. Accuracy of penicillin allergy reporting. Am J Hosp Pharm 1994;51:79-84.