In vitro and in vivo study results were reviewed from
cefmetazole, a "new" parenteral
cephamycin.
Cefmetazole's spectrum of activity was comparable to that of
second-generation cephalosporins, which includes clinical coverage of many Enterobacteriaceae, Staphylococcus spp., streptococci, Haemophilus spp., pathogenic Neisseria, Branhamella catarrhalis, and anaerobic bacteria.
Cefmetazole was generally more potent (two- to eightfold) than
cefoxitin against organisms within their spectrums and was particularly active for staphylococci (MIC90, 2.0 micrograms/ml). Methicillin-resistant S. aureus strains were more susceptible to
cefmetazole alone or in combination (
fosfomycin) than any other
cephamycin.
Cefmetazole has demonstrated excellent stability to aerobic and anaerobic organism-produced
beta-lactamases. It also inhibits Type I cephalosporinases and, uniquely, some other cephalosporinases produced by the Bacteroides. This superior stability, enzyme interaction, and better penetration into bacterial cells results in a sustained bactericidal effect and a capacity for more infrequent dosing. The
cefmetazole serum elimination half-life was 1.5 hr, also justifying use at greater than or equal to 8-hr intervals. Clinical trials in the United States and Japan demonstrated an acceptably high
cefmetazole infection cure rate (88% to 100%), especially in direct comparative studies with
cefoxitin.
Cefmetazole was also proven very effective in minimizing infectious
wound morbidity (prophylaxis) using 2 g single- or multidose regimens.
Adverse drug reactions were usually minor; in the Japanese surveillance trial (118,318 patients) the rate was only 2.2% (8.8% in United States).
Cefmetazole has been extensively and safely used in Japan since 1980.