What You Need to Know About Capecitabine Side Effects

If you've been prescribed Capecitabine (brand name Xeloda), it's normal to feel anxious about side effects. Capecitabine is an oral chemotherapy medication, and like all chemo drugs, it can cause a range of side effects — some mild and manageable, others serious enough to require immediate medical attention.

This guide covers what to expect, how to manage common side effects, and the warning signs that mean you should call your doctor right away. Being informed helps you stay safe and get the most out of your treatment.

What Is Capecitabine?

Capecitabine is a fluoropyrimidine antimetabolite — a type of oral chemotherapy that gets converted into the active drug 5-Fluorouracil (5-FU) inside your body, primarily in tumor tissue. It's FDA-approved to treat metastatic breast cancer, colon cancer (Dukes C/stage III), metastatic colorectal cancer, gastric cancer, pancreatic cancer, and esophageal cancer.

It's taken as a tablet twice daily for 14 days, followed by 7 days off, in 21-day cycles. Understanding the side effect profile can help you prepare and respond appropriately during treatment.

Common Side Effects of Capecitabine

These side effects are reported frequently in clinical trials and real-world use. While uncomfortable, most are manageable with your care team's guidance:

• Hand-foot syndrome (palmar-plantar erythrodysesthesia) — This is the most characteristic side effect of Capecitabine. You may notice redness, swelling, tingling, or pain on the palms of your hands and soles of your feet. In mild cases, the skin may feel tender or warm. This side effect is dose-related and often appears within the first few treatment cycles.
• Diarrhea — Loose or watery stools are common. Mild diarrhea can usually be managed at home, but severe diarrhea requires medical attention (more on this below).
• Nausea — Many patients experience mild to moderate nausea. Your doctor can prescribe anti-nausea medications to help.
• Vomiting — Less common than nausea, but it can occur, especially during the first few days of a cycle.
• Fatigue — Feeling tired or having low energy is one of the most common side effects of any chemotherapy, including Capecitabine.
• Loss of appetite — You may not feel like eating as much. Eating smaller, more frequent meals can help maintain nutrition.
• Stomatitis (mouth sores) — Painful sores or ulcers in the mouth and throat. Good oral hygiene and gentle mouthwashes can help prevent and manage this.
• Abdominal pain — Stomach cramps or discomfort in the abdomen area.
• Hyperbilirubinemia — Elevated bilirubin levels in blood tests, which your doctor will monitor through regular lab work.
• Dermatitis — Skin rashes, dryness, or itching beyond the hand-foot area.

Serious Side Effects: When to Call Your Doctor Immediately

Some side effects of Capecitabine can be life-threatening if not addressed quickly. Contact your oncologist or go to the emergency room if you experience any of the following:

Severe Diarrhea

If you have 4 or more loose stools per day above your normal, or diarrhea at night, call your doctor immediately. Severe diarrhea can lead to dangerous dehydration and electrolyte imbalances. Do not try to "push through" it — this is a medical emergency.

Cardiotoxicity (Heart Problems)

Capecitabine can affect the heart. Seek immediate medical attention if you experience:

• Chest pain or pressure
• Shortness of breath
• Irregular heartbeat
• Dizziness or fainting

Cardiotoxicity can include EKG changes, cardiomyopathy, and in rare cases, myocardial infarction (heart attack). Patients with a history of heart disease should be monitored closely.

Myelosuppression (Low Blood Counts)

Capecitabine can lower your white blood cells (neutropenia), red blood cells (anemia), and platelets (thrombocytopenia). Signs to watch for include:

• Fever of 100.4°F or higher (may signal infection due to low white blood cells)
• Unusual bruising or bleeding
• Extreme fatigue or weakness
• Pale skin

DPD Deficiency Reactions

This is critical: some people have a genetic condition called DPD deficiency (dihydropyrimidine dehydrogenase deficiency) that makes them unable to break down 5-FU safely. In patients with complete DPD deficiency, Capecitabine can cause severe, life-threatening toxicity including severe mucositis, neutropenia, and neurotoxicity. Your doctor should test for DPD deficiency before starting treatment.

Severe Hand-Foot Syndrome

While mild hand-foot syndrome is common, severe cases — with blistering, ulceration, or pain that prevents normal activities — require dose adjustment or treatment interruption. Do not wait for your next appointment; call your doctor.

Dangerous Bleeding (Warfarin Interaction)

Capecitabine has a boxed warning about its interaction with Warfarin and other blood thinners. If you take Warfarin, your INR levels must be monitored frequently. Signs of dangerous bleeding include unusual bruising, blood in urine or stool, and bleeding that won't stop.

Side Effects in Specific Populations

Older Adults (65 and Older)

Patients aged 60 and older may experience a greater incidence and severity of side effects, including diarrhea, nausea, and hand-foot syndrome. Closer monitoring and dose adjustments are often needed.

Patients with Kidney Problems

If you have moderate kidney impairment (creatinine clearance 30–50 mL/min), your doctor will reduce your dose. Capecitabine is contraindicated in patients with severe kidney impairment (creatinine clearance below 30 mL/min).

Patients with Liver Problems

If you have liver metastases or mild-to-moderate liver dysfunction, your doctor will monitor you carefully. Liver function tests are done regularly during treatment.

Pregnancy

Capecitabine is classified as Pregnancy Category D — it can cause harm to an unborn baby. Women of childbearing potential should use effective contraception during treatment and discuss family planning with their oncologist.

How to Manage Side Effects

Here are practical tips to help you cope with common Capecitabine side effects:

For Hand-Foot Syndrome

• Apply thick moisturizing creams (like Udderly Smooth, Bag Balm, or urea-based creams) to hands and feet regularly
• Wear soft, comfortable shoes and cotton socks
• Avoid hot water, tight gloves, and activities that put pressure on your hands and feet
• Report any redness, tingling, or pain to your doctor early — catching it early prevents worsening

For Diarrhea

• Stay hydrated — drink clear fluids throughout the day
• Follow the BRAT diet (bananas, rice, applesauce, toast) during flare-ups
• Your doctor may recommend Loperamide (Imodium) for management
• Call your doctor if you have more than 4 episodes per day

For Nausea and Vomiting

• Take anti-nausea medications as prescribed
• Eat smaller, more frequent meals
• Avoid strong smells and greasy foods
• Ginger tea or ginger supplements may provide mild relief

For Mouth Sores

• Brush gently with a soft toothbrush
• Rinse with a baking soda and salt water solution (1/2 tsp each in 8 oz water)
• Avoid spicy, acidic, or rough-textured foods
• Ask your doctor about prescription mouth rinses if sores are severe

For Fatigue

• Rest when you need to, but try to stay lightly active (short walks can help)
• Prioritize sleep and keep a regular schedule
• Ask for help with daily tasks during treatment cycles
• Report extreme fatigue to your doctor, as it may signal low blood counts

Final Thoughts

Side effects are a reality of chemotherapy, but understanding them puts you in control. Most common Capecitabine side effects are manageable with the right strategies and support from your care team. The key is knowing what's normal, what's not, and when to pick up the phone.

Always keep your oncologist's contact number handy, and don't hesitate to call — even outside of office hours — if something feels wrong. Many cancer centers have 24/7 nurse lines for exactly this reason.

For more about how Capecitabine works and what it's used for, read our plain-English guide to Capecitabine's mechanism of action. And if you need help finding Capecitabine at a pharmacy near you, Medfinder can help.