Imipenem allergic reactions

A retrospective analysis of allergic reactions (drug-induced fever and rash) in 90 adults with cystic fibrosis, of whom 26 developed probable allergic reactions to parenteral beta-lactams. There was drug-induced fever in 54 and skin reactions in 28 of 897 treatment courses (6 and 3.1% respectively). There was one case of non-fatal anaphylaxis. The numbers of allergic reactions per number of patients receiving specific antibiotics were carbenicillin 4/56, mezlocillin 7/42, piperacillin 11/31, ticarcUlin 1/20, cefazolin 0/24, ceftazidime 1/35, imipenem + cilastatin 4/16, and nafcillin 3/36 (17). 

The most common adverse effects of carbapenems—which tend to be more common with imipenem—are nausea, vomiting, diarrhea, skin rashes, and reactions at the infusion sites. Excessive levels of imipenem in patients with renal failure may lead to seizures. Meropenem, doripenem, and ertapenem are much less likely to cause seizures than imipenem. Patients allergic to penicillins may be allergic to carbapenems as well. 

There was a high degree of cross-reactivity between imipenem determinants, analogous to the penicillin determinants in penicillin-allergic patients. Nine of twenty patients with positive penicillin skin tests had positive skin reactions to analogous imipenem determinants (40). In view of this appreciable cross-reactivity, imipenem should not be given to patients with penicillin allergy. 

Nausea and vomiting are the most common side effects. Seizures have been noted in up to 1.5% of patients, especially when high doses are given to patients with CNS lesions or with renal insufficiency. Patients who are allergic to other jS-lactam antibiotics may have hypersensitivity reactions to imipenem. 

The question of tolerability of penicillins, monobactams, and carbapenems in patients with IgE hypersensitivity to cephalosporins was recently assessed in 98 subjects by serum IgE antibody assays, challenge tests, and skin testing with penicillin reagents, aztreonam, imipenem-cilastatin, and meropenem. Approximately 25 % of cephalosporin-allergic subjects were positive to penicillins, while 3.1,2, and 1 % showed positive results to aztreonam, imipenem, and meropenem, respectively. A reaction to a cephalosporin with a similar or identical side chain to penicillin was a sigifificant predictor of cross-reactivity. For skin testing, the following concentrations were used ampicillin and amoxicillin 1 and 20 mg/ml cephalosporins 2 mg/ml aztreonam 2 mg/ml imipenem-cilastatin 0.5 mg/ml and meropenem 1 mg/ml. 

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