DBL Fluorouracil Mechanism of Action

Pharmacology: Pharmacodynamics: Mechanism of action: Fluorouracil is an analogue of uracil, a component of ribonucleic acid. The drug is believed to function as an antimetabolite. Fluorouracil itself is inactive, and is converted intracellularly to active metabolites. After conversion to the active deoxynucleotide, it interferes with the synthesis of DNA by blocking the conversion of deoxyuridylic acid to thymidylic acid by the cellular enzyme thymidylate synthetase. Fluorouracil may also interfere with RNA synthesis.
Clinical trials: No data available.
Pharmacokinetics: After intravenous administration, fluorouracil is distributed through the body water. The plasma half-life is 8 to 22 minutes and is dose dependent. Fluorouracil disappears from the blood within 4 hours. It is preferentially taken up by actively dividing tissues and tumours after conversion to its nucleotide. Fluorouracil readily enters the cerebrospinal fluid (CSF).
About 20% is excreted unchanged in the urine and the remainder is mostly metabolised in the liver by the usual body mechanisms for uracil.