The chemical structure of cefmetazole, like that of several other cephalosporins, contains an
N-methylthiotetrazole (NMTT or 1-MTT)
side chain. As the antibiotic is broken down in the body, it releases free NMTT, which can cause
hypoprothrombinemia (likely due to
inhibition of the
enzyme vitamin K epoxide reductase) and a reaction with ethanol similar to that produced by
disulfiram, due to inhibition of
aldehyde dehydrogenase. ==Spectrum of bacterial susceptibility==