Floxuridine is a pyrimidine analog that acts as an inhibitor of the S-phase of cell division. This selectively kills rapidly dividing cells. Floxuridine is an anti-metabolite. Anti-metabolites masquerade as pyramidine-like molecules which prevents normal pyrimidines from being incorporated into DNA during the S phase of the cell cycle. Flurouracil (the end-product of catabolism of floxuridine) blocks an enzyme which converts cytosine nucleosides into the deoxy derivative. In addition, DNA synthesis is further inhibited because fluoruracil blocks the incorporation of the thymdine nucleotide into the DNA strand. Floxuridine is used for palliative management of gastrointestinal adenocarcinoma metastatic to the liver, when given by continuous regional intra-arterial infusion in carefully selected patients who are considered incurable by surgery or other means. Also for the palliative management of liver cancer (usually administered by hepatic intra-arterial infusion).Floxuridine first gained FDA approval in December 1970 under the brand name FUDR. The drug was initially marketed by Roche, which also did a lot of the initial work on 5-fluorouracil. The National Cancer Institute was an early developer of the drug. Roche sold its FUDR product line in 2001 to F H Faulding, which became Mayne Pharma.

Hydroxyurea is an oral antimetabolite; inhibits ribonucleotide reductase and DNA synthesis. It is used for resistant chronic myeloid leukemia, locally advanced squamous cell carcinomas of the head and neck (excluding lip) in combination with concurrent chemoradiation, and to reduce the frequency of painful crises and the need for blood transfusions in patients with sickle cell anemia with recurrent moderate to severe painful crises. Hydroxyurea, a myelosuppressive agent, is the only effective drug proven to reduce the frequency of painful episodes. It raises the level of HbF and the haemoglobin level. It usually decreases the rate of painful episodes by 50%. It was first tested in sickle cell disease in 1984. It also decreases the rate of ACS episodes and blood transfusions by ~50 % in adults. It was developed as an anticancer drug and has been used to treat myeloproliferative syndromes-leukemia, melanoma, and ovarian cancer. It was approved for use by FDA in adults. Side effects includes neutropenia, bone marrow suppression, elevation of hepatic enzymes, anorexia, nausea, vomiting and infertility.