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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Nucleoside Metabolic Inhibitor [EPC]
Capecitabine is an orally administered fluoropyrimidine carbamate, functioning as a nucleoside metabolic inhibitor and a prodrug of 5-fluorouracil. It is primarily utilized in the treatment of metastatic colorectal and breast cancers.
Name
Capecitabine
Raw Name
CAPECITABINE
Category
Nucleoside Metabolic Inhibitor [EPC]
Drug Count
5
Variant Count
39
Last Verified
February 17, 2026
RxCUI
200327, 200328, 213292, 213293
UNII
6804DJ8Z9U
About Capecitabine
Capecitabine is an orally administered fluoropyrimidine carbamate, functioning as a nucleoside metabolic inhibitor and a prodrug of 5-fluorouracil. It is primarily utilized in the treatment of metastatic colorectal and breast cancers.
Detailed information about Capecitabine
References used for this content
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Capecitabine.
Capecitabine (brand name Xeloda) is a sophisticated antineoplastic (anti-cancer) medication that belongs to the pharmacological class known as nucleoside metabolic inhibitors, specifically a fluoropyrimidine carbamate. It is an oral prodrug, meaning it is inactive when swallowed and must be converted within the body into its active form, 5-fluorouracil (5-FU). This conversion process is uniquely designed to occur preferentially within tumor cells, theoretically reducing the systemic exposure of healthy tissues to the toxic effects of chemotherapy.
First approved by the U.S. Food and Drug Administration (FDA) in 1998 for metastatic breast cancer and later in 2001 for colorectal cancer, Capecitabine represented a significant milestone in oncology. Before its development, patients requiring 5-fluorouracil therapy often had to undergo continuous intravenous infusions, which required permanent venous access devices (ports) and portable infusion pumps. Capecitabine offered a 'chemotherapy in a pill' alternative, providing similar efficacy with the convenience of home administration.
The mechanism of action for Capecitabine is a three-step enzymatic conversion process. Once ingested, Capecitabine is absorbed through the intestinal mucosa and travels to the liver. In the liver, the enzyme hepatic carboxylesterase converts it to 5'-deoxy-5-fluorocytidine (5'-DFCR). Subsequently, cytidine deaminase, an enzyme found in the liver and various tumor tissues, converts 5'-DFCR into 5'-deoxy-5-fluorouridine (5'-DFUR).
The final and most critical step occurs when the enzyme thymidine phosphorylase (TP) converts 5'-DFUR into the active drug, 5-fluorouracil (5-FU). Clinical research has demonstrated that many solid tumors, particularly those in the breast and colon, express higher levels of thymidine phosphorylase than normal healthy tissues. This differential expression allows for a higher concentration of the active cytotoxic (cell-killing) agent to be generated specifically at the site of the malignancy.
Once converted to 5-FU, the drug exerts its effects through two primary pathways. First, it mimics uracil, a building block of RNA, and incorporates itself into the RNA strand, causing 'transcriptional errors' that prevent the cell from producing necessary proteins. Second, its metabolite (FdUMP) binds to and inhibits thymidylate synthase, an enzyme essential for the synthesis of thymidine. Without thymidine, the cell cannot produce DNA, leading to a 'thymineless death' of the rapidly dividing cancer cells.
Understanding how the body processes Capecitabine is vital for optimizing therapy and managing toxicity.
Capecitabine is FDA-approved for several specific oncological indications:
Off-label uses, which are common in oncology based on clinical trials, include the treatment of esophageal, gastric, hepatobiliary, and pancreatic cancers. Your oncologist will determine the most appropriate use based on the specific molecular profile of your tumor and your overall health status.
Capecitabine is available exclusively as an oral tablet. Common strengths include:
These tablets are film-coated and should be swallowed whole with water. Because they are cytotoxic (hazardous) medications, they should be handled with care, and caregivers should ideally wear gloves when touching the tablets to avoid accidental absorption through the skin.
> Important: Only your healthcare provider can determine if Capecitabine is right for your specific condition. This medication is a potent chemotherapy agent that requires close supervision by an oncology specialist.
The dosage of Capecitabine is highly individualized and is calculated based on a patient's Body Surface Area (BSA), which is determined by height and weight.
The safety and effectiveness of Capecitabine in pediatric patients (under the age of 18) have not been established. There are currently no FDA-approved indications for Capecitabine in children. Clinical trials in pediatric populations are limited, and use in this group would be considered highly experimental and only under strict clinical trial protocols.
Kidney function is critical for the clearance of Capecitabine metabolites.
While the liver is responsible for the first step of activation, studies in patients with mild-to-moderate liver impairment due to liver metastases showed that no initial dose adjustment is required. However, these patients must be monitored very closely for toxicity, as liver function can change rapidly during cancer treatment.
Patients over the age of 60 are at a significantly higher risk for severe gastrointestinal toxicity (nausea, vomiting, diarrhea) and Hand-Foot Syndrome. Physicians often start elderly patients at a reduced dose or monitor them with extreme frequency, especially during the first two cycles of treatment.
If you miss a dose of Capecitabine, do not take the missed dose when you remember. Skip the missed dose entirely and wait until your next scheduled dose time. Never double the dose to make up for a missed one. Chemotherapy requires precise levels; taking too much at once can lead to severe toxicity. Inform your oncology team if you miss more than one dose.
Signs of a Capecitabine overdose may include severe nausea, vomiting, diarrhea, gastrointestinal bleeding, bone marrow suppression (leading to infection or bruising), and severe skin reactions.
In the event of a suspected overdose, contact your local poison control center or seek emergency medical attention immediately. Treatment is primarily supportive, focusing on managing symptoms and preventing dehydration or infection.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking the medication without medical guidance, even if you feel better or experience side effects.
Capecitabine is associated with several frequent side effects that patients should be prepared to manage in coordination with their medical team:
> Warning: Stop taking Capecitabine and call your doctor immediately if you experience any of these symptoms. These are signs of severe toxicity that may require hospitalization.
While many side effects resolve after the drug is stopped, some long-term effects may persist:
Warfarin Interaction Warning: Capecitabine has a significant interaction with warfarin (Coumadin). It can dramatically increase the blood-thinning effects of warfarin, leading to life-threatening bleeding or hemorrhage. This can occur within days of starting Capecitabine and up to a month after stopping it. Patients taking warfarin must have their PT/INR (clotting tests) monitored very frequently.
Report any unusual symptoms or changes in your health to your healthcare provider immediately. Early intervention is the key to continuing Capecitabine therapy safely.
Capecitabine is a high-potency cytotoxic medication. It must only be prescribed by a physician experienced in the use of antineoplastic agents. Patients must be educated on the 'Stop Rules'—knowing exactly when to hold a dose if toxicity occurs. Because Capecitabine is an oral medication, the responsibility for monitoring daily side effects falls largely on the patient and their caregiver. Failure to stop the medication at the first sign of moderate toxicity can lead to rapid clinical deterioration.
Interaction with Warfarin (Coumadin): The FDA has issued a Black Box Warning regarding the use of Capecitabine in patients taking warfarin. Clinical trials and post-marketing reports have shown clinically significant increases in prothrombin time (PT) and International Normalized Ratio (INR) in patients receiving both drugs. This interaction can lead to fatal bleeding episodes. If co-administration is absolutely necessary, INR must be monitored with extreme frequency (often several times a week), and the warfarin dose must be adjusted accordingly.
Your doctor will require regular laboratory tests to ensure the drug is not causing hidden damage:
Capecitabine may cause dizziness, fatigue, or nausea. If you experience these symptoms, you should avoid driving or operating heavy machinery until the symptoms resolve. Most patients can drive normally, but caution is advised during the first cycle of treatment when you do not yet know how your body will react to the drug.
While there is no direct contraindication between alcohol and Capecitabine, alcohol can worsen certain side effects. Alcohol can irritate the lining of the mouth and gastrointestinal tract, potentially worsening stomatitis and diarrhea. It can also contribute to dehydration. It is generally recommended to limit alcohol intake during chemotherapy.
Capecitabine does not require a tapering period (gradually reducing the dose). It can be stopped abruptly if toxicity occurs. In fact, the standard protocol for managing side effects is the 'Hold and Restart' method: the drug is stopped until the side effect resolves to Grade 0 or 1, and then restarted, often at a lower dose. Do not stop the drug for more than a day without informing your oncologist, as this may affect the efficacy of your cancer treatment.
> Important: Discuss all your medical conditions, especially heart disease, kidney disease, or a known DPD deficiency, with your healthcare provider before starting Capecitabine.
For each major interaction, the primary concern is either the increase in toxicity (making the drug dangerous) or the reduction in efficacy (making the cancer treatment fail). Management usually involves dose adjustment, increased monitoring, or choosing an alternative medication.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter pain relievers and vitamins.
There are several scenarios where Capecitabine must never be used because the risks far outweigh any potential benefits:
These conditions require a careful risk-benefit analysis by the oncologist:
Patients who have experienced severe toxicity or allergic reactions to 5-fluorouracil (5-FU) (often given as an IV infusion like Adrucil) are highly likely to have the same reaction to Capecitabine. Because Capecitabine is a prodrug of 5-FU, the active molecule is identical. If you have ever had a 'bad reaction' to IV chemotherapy for colon or breast cancer, it is vital to tell your doctor the name of that drug.
> Important: Your healthcare provider will evaluate your complete medical history, including genetic testing for DPD deficiency in some cases, before prescribing Capecitabine.
FDA Pregnancy Category D: Capecitabine can cause fetal harm when administered to a pregnant woman. In animal studies, Capecitabine was found to be teratogenic (causing birth defects) and embryolethal (causing fetal death) at doses lower than the human therapeutic dose.
It is not known whether Capecitabine or its metabolites are excreted in human breast milk. However, because many drugs are excreted in milk and because of the potential for serious adverse reactions in nursing infants, women are advised to discontinue breastfeeding during treatment with Capecitabine and for at least 2 weeks after the final dose.
Capecitabine is not approved for use in children. The pharmacokinetics and safety profile in pediatric patients have not been established. In the rare instances where it is used (e.g., specific pediatric brain tumors), it is done so only within the context of a controlled clinical trial at a specialized pediatric oncology center.
Patients over 65 years of age are at an increased risk for Grade 3 or 4 toxicities compared to younger patients. Specifically:
As the kidneys are the primary route of elimination for the inactive but potentially toxic metabolite FBAL (fluoro-beta-alanine), renal function is the most important factor in Capecitabine safety.
Physicians use the Cockcroft-Gault equation to calculate CrCl before every cycle.
Patients with mild-to-moderate hepatic dysfunction due to liver metastases do not typically require an initial dose adjustment. However, Capecitabine has not been adequately studied in patients with severe hepatic impairment (e.g., cirrhosis), and such patients should be treated with extreme caution.
> Important: Special populations require individualized medical assessment and more frequent laboratory monitoring to ensure safety.
Capecitabine is a fluoropyrimidine carbamate. It is a systemic prodrug of 5-fluorouracil (5-FU). The molecule is designed to be stable during gastrointestinal absorption but undergoes a three-step enzymatic conversion to 5-FU. The final step is catalyzed by thymidine phosphorylase (TP). TP is significantly more active in many tumor tissues compared to normal tissues, which allows for the preferential release of 5-FU within the tumor microenvironment. Once converted, 5-FU inhibits DNA synthesis and slows tumor growth by inhibiting thymidylate synthase and incorporating into RNA.
The cytotoxic effect of Capecitabine is schedule-dependent. Because it acts on the S-phase of the cell cycle (when DNA is being synthesized), maintaining therapeutic levels over a 14-day period is more effective than a single large dose. There is a clear dose-response relationship, but the 'therapeutic window' is narrow—meaning the dose required to kill cancer cells is very close to the dose that causes significant toxicity to the patient.
| Parameter | Value |
|---|---|
| Bioavailability | High (when taken with food) |
| Protein Binding | ~54% (primarily albumin) |
| Half-life | 0.5 to 1 hour (parent and 5-FU) |
| Tmax | 1.5 to 2 hours |
| Metabolism | Hepatic (CES1/2, CDA) and Tumor (TP) |
| Excretion | Renal 95%, Fecal <3% |
Capecitabine is classified as an Antimetabolite and a Nucleoside Metabolic Inhibitor. It is part of the fluoropyrimidine family, which includes other drugs like 5-fluorouracil (IV) and trifluridine/tipiracil (Lonsurf). Within oncology, it is considered a 'cycle-active' cytotoxic agent.
> Important: Pharmacology data is based on the FDA-approved professional labeling and clinical pharmacokinetic studies.
Medications containing this ingredient
Common questions about Capecitabine
Capecitabine is primarily used to treat cancers of the colon, rectum, and breast. In colon cancer, it is used both as an adjuvant treatment (after surgery to prevent recurrence) and for metastatic disease that has spread to other organs. For breast cancer, it is often prescribed when other chemotherapy drugs, such as anthracyclines or taxanes, have stopped working. It works by slowing or stopping the growth of cancer cells by interfering with their DNA production. Your oncologist will determine if it should be used alone or in combination with other chemotherapy agents.
The most frequent side effects include Hand-Foot Syndrome, diarrhea, nausea, fatigue, and mouth sores. Hand-Foot Syndrome causes redness, swelling, and pain on the palms of the hands and soles of the feet. Diarrhea is also very common and can become severe if not managed quickly with fluids and medication. Many patients also experience stomach pain, loss of appetite, and a temporary drop in white blood cell counts. Most of these side effects are manageable by temporarily stopping the medication or adjusting the dose under a doctor's supervision.
There is no known direct chemical interaction between alcohol and Capecitabine, but caution is highly recommended. Alcohol can irritate the mouth and stomach, which may worsen mouth sores (stomatitis) and diarrhea caused by the drug. Additionally, both alcohol and chemotherapy can be taxing on the liver and can contribute to dehydration. It is best to discuss your alcohol consumption with your oncologist to see what is safe for your specific situation. Generally, an occasional drink may be fine, but heavy drinking should be avoided during treatment.
No, Capecitabine is not considered safe during pregnancy and is classified as FDA Category D. It can cause significant birth defects or the death of an unborn baby if taken during pregnancy. Women of childbearing age must use effective birth control while taking the drug and for at least six months after the final dose. Men with female partners should also use contraception during and for three months after treatment. If you become pregnant while taking this medication, you must notify your doctor immediately to discuss the risks.
Capecitabine begins working at the cellular level shortly after the first few doses, but its effects on a tumor are not immediate. Most oncologists will evaluate the effectiveness of the treatment after two or three cycles (about 6 to 9 weeks) using imaging tests like CT scans or PET scans. Some patients may also have 'tumor markers' (blood tests like CEA for colon cancer) monitored to see if the levels are decreasing. It is important to complete the full course of treatment as prescribed by your doctor, even if you do not 'feel' the drug working right away.
Yes, you can stop taking Capecitabine suddenly, and in many cases, you are actually instructed to do so if you experience moderate to severe side effects. Unlike some medications that require tapering, Capecitabine is often 'held' (stopped for a few days) to allow your body to recover from toxicity. However, you should never stop taking it for more than one dose without consulting your oncology team. Stopping the medication for too long can allow the cancer to begin growing again, so any breaks in treatment must be medically managed.
If you miss a dose of Capecitabine, you should skip that dose entirely and take your next dose at the regularly scheduled time. Do not take the missed dose later in the day, and never take two doses at once to make up for a missed one. Taking too much chemotherapy at one time can lead to dangerous levels of toxicity in your body. It is helpful to keep a 'dose diary' to track when you take your medication. If you miss multiple doses, contact your doctor to see if your treatment schedule needs to be adjusted.
Weight gain is not a common side effect of Capecitabine; in fact, weight loss is much more frequent. Weight loss usually occurs due to side effects like nausea, vomiting, loss of appetite, and diarrhea, which can reduce your caloric intake. If you notice rapid weight gain, it is more likely due to fluid retention (edema), which can sometimes happen if the drug affects your heart or kidneys. You should report any significant changes in weight—either up or down—to your healthcare provider during your regular check-ups.
Capecitabine can interact with several other medications, some of which are very serious. The most dangerous interaction is with the blood-thinner warfarin (Coumadin), which can lead to life-threatening bleeding. It can also interact with phenytoin (a seizure medication) and certain antacids. Because of these risks, you must provide your doctor with a complete list of all prescription drugs, over-the-counter medicines, vitamins, and herbal supplements you are taking. Your doctor will monitor you closely for interactions and may adjust your doses accordingly.
Yes, Capecitabine is available as a generic medication. The brand name version is Xeloda, but several manufacturers now produce generic Capecitabine tablets in both 150 mg and 500 mg strengths. Generic versions are required by the FDA to have the same active ingredient, strength, dosage form, and route of administration as the brand-name drug. Using the generic version can significantly lower the cost of treatment for many patients. You should check with your insurance provider and pharmacist to see which version is covered under your plan.