Antimetabolite

[2] Antimetabolites can be used in cancer treatment,[3] as they interfere with DNA production and therefore cell division and tumor growth.

Examples of cancer drug antimetabolites include, but are not limited to the following: Anti-metabolites masquerade as a purine (azathioprine, mercaptopurine) or a pyrimidine, chemicals that become the building-blocks of DNA.

[9] PABA is needed in enzymatic reactions that produce folic acid, which acts as a coenzyme in the synthesis of purines and pyrimidines, the building-blocks of DNA.

Mammals do not synthesize their own folic acid so they are unaffected by PABA inhibitors, which selectively kill bacteria.

Antimetabolites, particularly mitomycin C (MMC), are commonly used in America and Japan as an addition to trabeculectomy, a surgical procedure to treat glaucoma.

2D chemical structural diagrams comparing folic acid and methotrexate
The drug methotrexate (bottom) is an antimetabolite that interferes with the metabolism of folic acid (top)