To the Editor: Ampicillin (Polycillin, Penbritin, Omnipen) administration resulted in skin rashes in 17% of patients recently reported by Breese et al. An alarmingly high incidence of sensitivity reactions to this new semisynthetic penicillin has been our experience as well. What are the implications of the ampicillin skin rash? Are these patients now sensitized to all penicillins? Since the common nucleus of all penicillins is 6-aminopenicillanic acid, and this is thought to be the antigen, it may be that ampicillin administration is setting the stage for severe hypersensitivity responses in about one out of six patients who receive it.
Unless this grim possibility can be ruled out, should we not relegate ampicillin to the role of a special-purpose, high-risk antibiotic?