Pyrimidine antimetabolites, anticancer

Classification and pharmacokinetics 5-FC is a pyrimidine antimetabolite related to the anticancer drug 5-fluorouracil. It is effective orally and is distributed to most body tissues, including the CNS. The drug is eliminated intact in the urine, and the dose must be reduced in patients with renal impairment. 

Whether the P5C-activated mechanism is abnormal in tumors must await future studies. Nevertheless, the P5C-mediated increase in PP-ri-bose-P may be useful in anticancer chemotherapy. Because the PP-ri-bose-P-dependent conversion of purine and pyrimidine antimetabolites... 

Cells are able to synthesize genetic material (DNA, RNA) from endogenous metabolites known as purine and pyrimidine nucleotides (Fig. 36-3). Certain anticancer drugs are structurally similar to these endogenous metabolites and compete with these compounds during DNA/RNA biosynthesis. These drugs are therefore called antimetabolites because they interfere with the normal metabolites during cellular biosynthesis.16,80... 

In summary, capecitabine (1), an A -carbamate pyrimidine nucleoside prodrug of cytotoxic antimetabolite 5-fluorouracil, is an FDA-approved anticancer drug that can be administered orally. This compound uses a multilayer of prodrug strategies that not only avoids side effects arising from exposure of toxic metabolites to healthy tissue but is converted to 5-fluorouracil only by enzymes preferentially expressed in many cancer cell types, thus resulting in selective delivery of the drug to tumors. Capecitabine is marketed under the trade name of Xeloda for use in the treatment of metastatic colorectal and breast cancers and metastatic breast cancer that is resistant to paclitaxel or anthracycline therapies. 

Cytamen cyanocobalamin. cytarabine [ban, inn. jan, usan] (cytarabine hydrochloride [usan] Ara C Cytosar Cytosar-U ) is an antimetabolite cytotoxic ANTICANCER and ANTIVIRAL AGENT isolated from the mushroom Xerocomm nigromaculatus. It works by interfering with pyrimidine synthesis. Clinically, it can be used sys-temically in anticancer treatment mainly of acute leukaemia, cytidine diphosphate choline dticoline. cytidine diphosphocholine dticoline. cytisine is an alkaloid with CNS STIMULANT, RESPIRATORY STIMULANT and psychoactive properties. It has been used clinically as a respiratory stimulant in Russia. It is a common cause of poisoning by the seeds of Cytisus laburnum. 

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