Nucleic acid inhibitor

antifungal flucytosine

quinolones act upon DNA gyrase as a topoisomerase inhibitor.^[2] Another group of DNA inhibitors, including nitrofurantoin and metronidazole, act upon anaerobic bacteria.^[3] These act by generating metabolites that are incorporated into DNA strands, which then are more prone to breakage.^[4] These drugs are selectively toxic to anaerobic organisms, but can affect human cells.^{[citation needed}

DNA-dependent RNA polymerase.^[5]

tetrahydrofolate is also involved in the synthesis of amino acids serine and methionine), so they are sometimes considered as their own category, antimetabolites.^[6] However, the term "antimetabolite", when used literally, can apply to many different classes of drugs.^{[citation needed}