Xitabin150 mg

Established / FDA-Approved Uses

• Metastatic breast cancer: Xitabin monotherapy is indicated for patients whose disease is resistant to both paclitaxel and an anthracycline-containing chemotherapy regimen, or in patients for whom further anthracycline therapy is not indicated (e.g., patients who have already received cumulative doses of 400 mg/m² or more of doxorubicin or doxorubicin equivalents). Xitabin is also indicated in combination with docetaxel for treatment of metastatic breast cancer after failure of prior anthracycline-containing chemotherapy.
• Colon cancer (adjuvant treatment): Xitabin is indicated as a single agent for adjuvant treatment of Dukes' C colon cancer in patients who have undergone complete resection of the primary tumor, when treatment with fluoropyrimidine therapy alone is preferred.
• Metastatic colorectal cancer: Xitabin is indicated as first-line treatment of metastatic colorectal cancer, alone or in combination with other chemotherapy agents, when treatment with a fluoropyrimidine alone is preferred.

Guideline-Supported / Combination Uses

• Used as part of combination chemotherapy regimens (e.g., with oxaliplatin, commonly referred to as CAPOX/XELOX) for colorectal cancer, based on oncology treatment guidelines.
• Used off-label, under oncologist supervision, as part of guideline-directed combination regimens in other gastrointestinal, gastric, and pancreatic cancers.

Xitabin is a cytotoxic chemotherapy medicine and must only be prescribed and monitored by a qualified oncologist or physician experienced in cancer chemotherapy.

Each film-coated tablet of Capecitabine contains 150 mg or 500 mg of capecitabine as the active ingredient, along with standard pharmaceutical excipients such as lactose, microcrystalline cellulose, croscarmellose sodium, hypromellose, and magnesium stearate (exact formulation may vary by manufacturer).

Xitabin is an orally administered fluoropyrimidine carbamate that acts as a prodrug of 5-fluorouracil (5-FU). It is designed to be selectively activated within tumor tissue, generating cytotoxic 5-FU preferentially at the tumor site rather than in normal tissue. Xitabin is used in the treatment of certain solid tumors, most notably breast cancer and colorectal cancer, and is administered as tablets under the close supervision of an oncology specialist.

Xitabin belongs to the therapeutic class of antineoplastic agents, specifically the fluoropyrimidine carbamates, a subclass of antimetabolite chemotherapy drugs.

Capecitabine itself is pharmacologically inactive; it undergoes a three-step enzymatic conversion in the body. It is first hydrolyzed in the liver by carboxylesterase to 5'-deoxy-5-fluorocytidine (5'-DFCR), which is then converted by cytidine deaminase (found mainly in the liver and in tumor tissue) to 5'-deoxy-5-fluorouridine (5'-DFUR). The final step converts 5'-DFUR to the active cytotoxic moiety, 5-fluorouracil (5-FU), by thymidine phosphorylase, an enzyme present in higher concentrations in tumor tissue than in normal tissue. This selective activation is intended to concentrate 5-FU at the tumor site. 5-FU is further metabolized to disrupt DNA synthesis and repair (via inhibition of thymidylate synthase) and to interfere with RNA processing, leading to cell death, particularly in rapidly dividing malignant cells.

Xitabin tablets should be swallowed whole with water within 30 minutes after a meal (breakfast and dinner), approximately 12 hours apart. Tablets must not be crushed or split unless specifically instructed. Caregivers should avoid direct skin contact with crushed or broken tablets, as Xitabin is a cytotoxic drug; hands should be washed thoroughly after handling. Doses should never be adjusted or stopped without consulting the prescribing oncologist.

Warfarin and Other Coumarin-Derivative Anticoagulants (Major)

Concurrent use of Xitabin with warfarin or other coumarin-derivative anticoagulants can significantly increase anticoagulant exposure, leading to elevated INR and serious, sometimes fatal, bleeding events. This interaction can occur days to months after starting Xitabin, or even after stopping it. Frequent monitoring of INR/prothrombin time and anticoagulant dose adjustment are required in patients receiving both drugs.

Phenytoin

Xitabin can increase phenytoin plasma concentrations, potentially leading to phenytoin toxicity; phenytoin levels should be monitored closely during concurrent use.

Leucovorin (Folinic Acid)

Leucovorin increases the toxicity of the active metabolite of Xitabin (5-fluorouracil) and may increase both efficacy and toxicity; combined use requires careful clinical monitoring.

Sorivudine and Related Antivirals (Brivudine)

Sorivudine and chemically related analogs (e.g., brivudine) markedly increase the toxicity of fluoropyrimidines and must never be co-administered with Xitabin (see Contraindications).

Other CYP2C9 Substrates

Xitabin may increase exposure to other drugs metabolized by CYP2C9; caution and monitoring are advised when such drugs are used concurrently.

Very Common / Common

• Diarrhea (can be severe and cause dehydration)
• Hand-foot syndrome (palmar-plantar erythrodysesthesia) — redness, swelling, pain, and peeling of the palms and soles; a notable, dose-limiting toxicity of Xitabin
• Nausea and vomiting
• Stomatitis (mouth sores) and abdominal pain
• Fatigue and weakness
• Loss of appetite

Serious / Less Common

• Myelosuppression: neutropenia, anemia, thrombocytopenia (increased risk of infection and bleeding)
• Cardiotoxicity: chest pain/angina, arrhythmias, and rarely myocardial infarction
• Severe skin reactions and mucositis
• Hyperbilirubinemia and liver enzyme abnormalities
• Eye irritation, excessive tearing, or corneal changes with prolonged use

Patients should seek prompt medical attention for severe or persistent diarrhea, fever, signs of infection, unusual bleeding or bruising, or severe hand-foot symptoms.

Xitabin is contraindicated during pregnancy. As a cytotoxic chemotherapy agent, it can cause fetal harm based on its mechanism of action and animal reproduction data; women of childbearing potential should use effective contraception during treatment and for a period after stopping Xitabin, and should be advised of the potential risk to the fetus. If pregnancy occurs during treatment, the patient should be informed of the potential hazard and referred for immediate medical evaluation.

Xitabin is also contraindicated during breastfeeding; breastfeeding should be discontinued during treatment due to the potential for serious adverse effects in the nursing infant.

Warfarin/Anticoagulant Bleeding Risk

See Interactions — concurrent use with warfarin or other coumarin anticoagulants requires frequent coagulation monitoring due to the risk of serious, sometimes fatal, bleeding.

Dihydropyrimidine Dehydrogenase (DPD) Deficiency

Patients with DPD deficiency are at increased risk of severe, life-threatening, or fatal toxicity from Xitabin. Testing for DPD deficiency may be considered before starting treatment; Xitabin should be withheld immediately in any patient who develops evidence of acute, early-onset, or unusually severe toxicity, which may indicate DPD deficiency.

Diarrhea and Dehydration

Severe diarrhea can occur and may require dose interruption, dose reduction, and aggressive rehydration; patients should be instructed to report diarrhea promptly.

Hand-Foot Syndrome

Monitor for palmar-plantar erythrodysesthesia; dose interruption or reduction may be required for moderate to severe cases (see Side Effects).

Myelosuppression

Regular monitoring of complete blood counts is recommended; treatment should be withheld for significant hematologic toxicity.

Cardiac Effects

Xitabin should be used with caution in patients with a history of coronary artery disease due to a risk of cardiotoxicity, including angina, arrhythmias, and myocardial infarction.

Renal and Hepatic Impairment

Dose adjustment is required in moderate renal impairment, and Xitabin is contraindicated in severe renal impairment. Use with caution and close monitoring in patients with hepatic impairment (see Dosage and Administration).

Elderly Patients

Elderly patients may be more susceptible to gastrointestinal toxicity from Xitabin and should be monitored closely (see Use in Special Populations).

General Handling

Xitabin is a cytotoxic drug; it should be handled and disposed of according to institutional guidelines for hazardous drugs, and should be taken exactly as prescribed by the treating oncologist — do not alter the dose, stop treatment, or share this medicine with others without medical advice.

Manifestations of Xitabin overdose may include nausea, vomiting, diarrhea, gastrointestinal irritation and bleeding, bone marrow suppression, and mucositis. There is no specific antidote for Xitabin overdose. In case of suspected overdose, seek immediate medical attention or contact emergency services/poison control; management is supportive and may include interruption of therapy, hospitalization, and treatment of the resulting toxicities, guided by the treating physician.

Store at room temperature (below 30°C), away from light and moisture, in the original packaging with the container tightly closed. Keep out of reach of children. Handle with care, as Xitabin is a cytotoxic medicine.

Renal Impairment

No adjustment is needed for mild impairment; a dose reduction is required for moderate impairment; Xitabin is contraindicated in severe renal impairment (see Dosage and Administration and Contraindications).

Hepatic Impairment

Use with caution and close monitoring in mild to moderate hepatic dysfunction due to liver metastases; Xitabin has not been studied in severe hepatic impairment.

Elderly (≥60–65 years)

Elderly patients receiving Xitabin, particularly in combination regimens, have shown higher rates of severe gastrointestinal toxicity; closer monitoring is recommended, though no specific starting dose reduction is required based on age alone.

Pediatric Patients

Safety and efficacy of Xitabin in pediatric patients have not been established (see Pediatric Uses).

Pregnancy and Lactation

See Pregnancy and Lactation — Xitabin is contraindicated in both.

Treatment with Xitabin is given in repeated 21-day cycles (14 days of therapy followed by a 7-day rest). For metastatic disease, treatment is generally continued until disease progression or unacceptable toxicity, as determined by the treating oncologist. For adjuvant treatment of Dukes' C colon cancer, the recommended duration is 8 cycles (approximately 24 weeks).

Antineoplastic agent; fluoropyrimidine carbamate; antimetabolite (prodrug of 5-fluorouracil).

Capecitabine is enzymatically converted in vivo to 5-fluorouracil (5-FU), with the final activation step catalyzed by thymidine phosphorylase, an enzyme present at higher levels in tumor tissue than in normal tissue. 5-FU is incorporated into RNA and inhibits thymidylate synthase, blocking DNA synthesis and repair, which leads to selective cytotoxicity against rapidly dividing cancer cells.

D

The safety and efficacy of Xitabin have not been established in pediatric patients. Xitabin is not recommended for use in children or adolescents outside of a clinical trial setting.