NCI Drug Dictionary

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The NCI Drug Dictionary contains technical definitions and synonyms for drugs/agents used to treat patients with cancer or conditions related to cancer. Each drug entry includes links to check for clinical trials listed in NCI's List of Cancer Clinical Trials.

extended-release flucytosine
An extended release (ER) oral tablet that contains flucytosine (5-FC), a fluorinated cytosine analog, with antifungal activity and potential anti-cancer activity. Following oral administration of ER 5-FC, the 5-FC is deaminated to its active metabolite 5-fluorouracil (5-FU). 5-FU replaces uracil during RNA synthesis, which consequently inhibits downstream protein synthesis. In addition, 5-FU is metabolized further to 5-fluorodeoxyuridylic acid monophosphate, which inhibits thymidylate synthetase. Inhibition of this enzyme interrupts nucleotide synthesis, DNA replication and cell proliferation. Negative regulation of protein synthesis, DNA replication and cell proliferation can lead to cell death. Following ingestion of ER 5-FC, intravenous injection of a retroviral vector encoding cytosine deaminase (TC 511) at a tumor site may result in higher local concentrations of 5-FU and its metabolites, and increased tumor cell death than other 5-FU treatment regimens. Check for active clinical trials using this agent. (NCI Thesaurus)

Synonym:extended release 5-FC
extended release 5-fluorocytosine
extended-release 5-FC
extended-release 5-fluorocytosine
US brand name:Toca FC