Drug Groups

approved

Description

A pyrimidine analog that is an antineoplastic antimetabolite. It interferes with DNA synthesis by blocking the thymidylate synthetase conversion of deoxyuridylic acid to thymidylic acid. [PubChem]

Indication

For the topical treatment of multiple actinic or solar keratoses. In the 5% strength it is also useful in the treatment of superficial basal cell carcinomas when conventional methods are impractical, such as with multiple lesions or difficult treatment sites. Fluorouracil injection is indicated in the palliative management of some types of cancer, including colon, esophageal, gastric, rectum, breast, biliary tract, stomach, head and neck, cervical, pancreas, renal cell, and carcinoid.

Pharmacology

Fluorouracil is an antineoplastic anti-metabolite. Anti-metabolites masquerade as purine or pyrimidine - which become the building blocks of DNA. They prevent these substances from becoming incorporated into DNA during the "S" phase (of the cell cycle), stopping normal development and division. Fluorouracil blocks an enzyme which converts the cytosine nucleotide into the deoxy derivative. In addition, DNA synthesis is further inhibited because Fluorouracil blocks the incorporation of the thymidine nucleotide into the DNA strand.

Toxicity

LD₅₀=230mg/kg (orally in mice)

Affected Organisms

Biotransformation

Hepatic

Absorption

28-100%

Half Life

10-20 minutes

Protein Binding

8-12%

Elimination

Seven percent to 20% of the parent drug is excreted unchanged in the urine in 6 hours; of this over 90% is excreted in the first hour.
The remaining percentage of the administered dose is metabolized, primarily in the liver.

References

External Links