capecitabine

Action

Enzymatically converts to 5-fluorouracil, which injures cells by interfering with DNA synthesis, cell division, RNA processing, and protein synthesis

Availability

Tablets: 150 mg, 500 mg

Indications and dosages

➣ Metastatic breast cancer resistant to both paclitaxel and a chemotherapy regimen that includes anthracycline; metastatic colorectal cancer when treatment with fluoropyrimidine therapy alone is preferred

Adults: Initially, 2,500 mg/m²/day P.O. in two divided doses for 2 weeks, followed by a 1-week rest period; administered in 3-week cycles

Dosage adjustment

• Renal impairment

• Hepatic impairment

• Elderly patients

Contraindications

• Hypersensitivity to drug

• Severe renal impairment

• Pregnancy or breastfeeding

Precautions

Use cautiously in:

• mild to moderate renal impairment, hepatic impairment, severe diarrhea, coronary artery disease, intestinal disease, infection, coagulopathy

• children younger than age 18.

Administration

• Give with water within 30 minutes after a meal.

• If dosage must be lowered because of toxicity, don't increase dosage later.

Adverse reactions

CNS: dizziness, fatigue, headache, insomnia, paresthesia

CV: edema

EENT: eye irritation

GI: nausea, vomiting, diarrhea, constipation, abdominal pain, dyspepsia, anorexia, stomatitis, intestinal obstruction

Hematologic: anemia, lymphopenia, neutropenia, thrombocytopenia

Metabolic: dehydration

Musculoskeletal: myalgia, limb pain

Skin: dermatitis, alopecia, nail disorder, hand and foot syndrome (palmarplantar erythrodysesthesia)

Other: fever

Interactions

Drug-drug. Antacids: increased capecitabine blood level

Leucovorin: increased cytotoxicity

Live-virus vaccines: impaired ability to mount an immune response to vaccine

Phenytoin: increased phenytoin blood level

Warfarin: increased risk of bleeding

Drug-diagnostic tests. Bilirubin: increased level

Hemoglobin, neutrophils, platelets, white blood cells: decreased levels

Patient monitoring

• Monitor patient for signs and symptoms of toxicity. Be prepared to reduce dosage or withhold drug when indicated.

• Stay alert for signs and symptoms of infection.

• Carefully assess fluid and electrolyte status if patient has severe diarrhea.

• Monitor weight, CBC, International Normalized Ratio, prothrombin time, and kidney and liver function test results.

• Evaluate closely for adverse reactions in patients older than age 80.

Patient teaching

• Advise patient to take drug with water within 30 minutes after a meal.

➣ Instruct patient to immediately report nausea, vomiting, diarrhea, mouth ulcers, swollen joints, temperature above 100.5 ^°F (38 ^°C), and other signs or symptoms of infection.

• Tell patient to expect dosage adjustments during therapy.

• Urge patient to use reliable birth control method because drug may harm fetus if she becomes pregnant.

• Caution patient not to breastfeed during therapy.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.