is a chemical with a similar structure to a substance (a metabolite
) required for normal biochemical reactions, yet different enough to interfere with the normal functions of cells, including cell division
Antimetabolites can be used in cancer
treatment, as they interfere with DNA production and therefore cell division and the growth of tumors. Because cancer cells spend more time dividing than other cells, inhibiting cell division harms tumor cells more than other cells.
Anti-metabolites masquerade as purine (azathioprine, mercaptopurine) or pyrimidine - which become the building blocks of DNA. They prevent these substances becoming incorporated in to DNA during the S phase (of the cell cycle), stopping normal development and division.
They also affect RNA synthesis. However, because thymidine is used in DNA but not in RNA (where uracil is used instead), inhibition of thymidine synthesis via thymidylate synthase selectively inhibits DNA synthesis over RNA synthesis.
Due to their efficiency, these drugs are the most widely used cytostatics.
In the ATC system, they are classified under L01B.
Antimetabolites may also be antibiotics
, such as sulfanilamide
drugs, which inhibit dihydrofolate
synthesis in bacteria by competing with para-aminobenzoic acid
Main representatives of these drugs are: