Cefotetan is an injectable antibiotic of the cephamycin type for prophylaxis and treatment of bacterial infections.

It is often grouped together with second-generation cephalosporins and has a similar antibacterial spectrum, but with additional anti-anaerobe coverage.

The chemical structure of cefotetan, 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 (Antabuse), due to inhibition of aldehyde dehydrogenase.

The following represents MIC susceptibility data for a few medically significant bacteria.