Imipenem in Patients with Immediate Hypersensitivity to Penicillins

To the Editor: It is considered potentially harmful to administer imipenem–cilastatin to patients with IgE-mediated hypersensitivity to penicillins 1 because of a 47.4 percent rate of cross-reactivity (9 of 19 subjects) found in a single study 2 on the basis of positive skin tests involving imipenem reagents. Between 1997 and 2005, we studied 112 consecutive patients with such hypersensitivity, diagnosed as previously described, 3 in order to assess the cross-reactivity with imipenem–cilastatin and to evaluate the allergic responses to imipenem–cilastatin in patients who had negative skin tests. Our patients had had a total of 143 immediate reactions to penicillins. All patients had positive . . .