NCIt definition : The sodium salt of ketotrexate, a synthetic antimetabolite analogue of folate with
antineoplastic activity. Upon administration, ketotrexate competes for the folate
binding site of the enzyme dihydrofolate reductase, resulting in inhibition of tetrahydrofolate
synthesis, depletion of nucleotide pools, and inhibition of DNA, RNA and protein synthesis.
(NCI04);