Enzymes convert capecitabine to 5-fluorouracil (5-FU) in vivo. Both normal and tumor cells metabolize 5-FU to 5-fluoro-2’-deoxyuridine monophosphate (FdUMP) and 5-fluorouridine triphosphate (FUTP). These metabolites cause cell injury by two different mechanisms. First, FdUMP and the folate cofactor, N5-10-methylenetetrahydrofolate, bind to thymidylate synthase (TS) to form a covalently bound ternary complex. This binding inhibits the formation of thymidylate from 2’-deoxyuridylate. Thymidylate is the necessary precursor of thymidine triphosphate, which is essential for the synthesis of DNA, so that a deficiency of this compound can inhibit cell division. Second, nuclear transcriptional enzymes can mistakenly incorporate FUTP in place of uridine triphosphate (UTP) during the synthesis of RNA.

1250 mg/m2 twice daily orally for 2 weeks followed by a one week rest period in 3-week cycles. Adjuvant treatment is recommended for a total of 6 months (8 cycles).

Take Capecitabine with water within 30 min after a meal.

Anticoagulants: Monitor anticoagulant response (INR or prothrombin time) frequently in order to adjust the anticoagulant dose as needed.

Phenytoin: Monitor phenytoin levels in patients taking Capecitabine concomitantly with phenytoin. The phenytoin dose may need to be reduced.

Leucovorin: The concentration of 5-fluorouracil is increased and its toxicity may be enhanced by leucovorin.

CYP2C9 substrates: Care should be exercised when Capecitabine is coadministered with CYP2C9 substrates.

Food reduced both the rate and extent of absorption of capecitabine.

Adjuvant Colon Cancer, Metastatic Colorectal Cancer, Metastatic Breast Cancer.

Most common adverse reactions (≥30%) were diarrhea, hand-and-foot syndrome, nausea, vomiting, abdominal pain, fatigue/weakness, and hyperbilirubinemia.

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