Cefmetazole sodium (Zefazone - Upjohn), a second-generation parenteral cephalosporin, was recently marketed in the USA for intravenous (IV) treatment of various infections caused by susceptible organisms. Like cefotetan (Cefotan), cefamandole (Mandol), cefoperazone (Cefobid), and moxalactam (Moxam), cefmetazole contains a methylthiotetrazole group that has been associated with prothrombin deficiency.

A penicillin is the drug of choice for treatment of many infections, but allergic reactions to these drugs occur frequently and, rarely, can be fatal. From 5% to 20% of patients have a history of a rash or some other reaction while taking a penicillin, but maculopapular rashes with ampicillin or amoxicillin, especially in children with infectious mononucleosis, are probably not allergic.