Heart Conditions Linked

Although rare, some people may have side effects linked to 5-fluorouracil (5FU) or capecitabine chemotherapies that affect their hearts. Up to 6 people out of 100 patients receiving this treatment have cardiac side effects, which may include chest pain, irregular heart rhythms, or heart failure.

While some people have no symptoms, others might feel chest pressure or pain, palpitations, or shortness of breath. If you feel these or other side effects, your doctor may do different heart tests. 

Chest Pain (Angina)

The most common heart symptom due to 5FU chemotherapy is chest pain or pressure and feels like you are having a heart attack. You may feel like your chest is being squeezed, or have a feeling of heaviness, pressure, weight, or tightness in your chest. You also may feel a burning in your chest. The pain can radiate to the shoulder, neck, jaw, arm or back. The chest pain may lessen when the chemotherapy is stopped.

If you experience chest pain, call 911 or go to the emergency room.

How Does Fluoropyrimidine Chemotherapy Cause Chest Pain?

Chest pain may happen because 5FU can affect the coronary arteries. These arteries sometimes spasm (coronary vasospasm) causing blood flow to decrease. When that happens, your heart muscle may not get enough oxygen and nutrients to function well. This causes pain. 

If you feel chest pain after having chemotherapy, call 911 and seek emergency care.

How is Fluoropyrimidine Chest Pain Treated?

Your doctor may order additional testing or imaging of your heart to guide further treatment and may give you medications (anti-anginals) that work to stop coronary vasospasm. These medications help relax the heart arteries and lessen the chest pain. The medications to treat 5FU or capecitabine cardiotoxicity are also ones that can affect your blood pressure. If you feel lightheaded, dizzy, or develop a headache, let your doctor know.

Irregular Heart Rhythms (Arrhythmias)

Normal heart function relies on a series of electrical events inside the heart that occur at the right time and in the right order. Another less common form of 5FU complications includes a heart rhythm problem, called an arrhythmia. An arrhythmia can mean your heart beats too fast or too slow. Your cancer doctor or treatment team may monitor your heart rhythm with an ECG.

Some patients may have palpitations — your heart beating rapidly and loudly in your chest — irregular heartbeat, skipped beats or other uncomfortable chest sensations. If you have these symptoms, feel lightheaded or dizzy, or if you faint while getting your chemotherapy, seek medical attention at once.

Heart Failure

Other less common complications from 5FU chemotherapy can include damage to the heart muscle causing the heart to weaken and not be able to pump blood well. This is known as a cardiomyopathy or heart failure and can result in fluid building up in your body causing:

• Swelling in the feet or legs
• Stomach or abdominal distension
• Difficulty breathing with exertion (such as going up a flight of stairs)
• Inability to lie flat on your back
• Waking up in the middle of the night feeling short of breath
• Sudden weight gain

If you experience any of these symptoms, talk to your doctor.