Cefmetazole (Zefazone) is a semisynthetic, third-generation,parenteral cephalosporin of the cephamycin group. Likeother cephamycins, the presence of the 7α-methoxyl groupconfers resistance to many β-lactamases. Cefmetazoleexhibits significantly higher potency against members ofthe Enterobacteriaceae family but lower activity againstBacteroides spp. than cefoxitin. It is highly active againstN. gonorrhoeae, including -lactamase–producing strains. Incommon with other cephamycins, cefmetazole is ineffectiveagainst indole-positive Proteus, Enterobacter, Providencia,Serratia, and Pseudomonas spp. Cefmetazole has the MTTmoiety associated with increased bleeding in certain highriskpatients. It has a plasma half-life of 1.1 hours.
