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Read more about the chemotherapy drug eribulin (Halaven), including how it works and the possible side effects.

1. What is eribulin?

Eribulin is a drug used to treat breast cancer. It’s also known by the brand name Halaven.

2. Who might be offered eribulin?

Eribulin is used to treat people who have:

  • Locally advanced breast cancer – breast cancer that has spread to the tissues and lymph nodes (glands) around the chest, neck and under the breastbone
  • Secondary (metastatic) breast cancer – breast cancer that has spread to other parts of the body

Eribulin is given after you’ve had previous treatment with other types of chemotherapy drugs.

3. Before starting eribulin

Before starting your treatment most hospitals will arrange a chemotherapy information session.

At this appointment your treatment team will discuss how and when your chemotherapy will be given and how side effects can be managed.

You may have blood tests and some people will have an ECG (electrocardiogram), a simple test that checks your heart rhythm.

Your height and weight will also be measured. This is used to work out the correct dose of chemotherapy for you.

Contact numbers will be given so you know who to phone if you have any questions or concerns.

4. How is eribulin given?

Eribulin is given into a vein. This will usually be as a drip, also called an infusion, into your hand or arm and takes two to five minutes.

Other methods may be used depending on factors such as how easy it is for the chemotherapy team to find suitable veins, and your preferences.

You can read about the different ways of giving chemotherapy on our chemotherapy page.

How long does treatment take?

A cycle of eribulin lasts 21 days, with treatment given on days 1 and 8 of the cycle. The time between each cycle of treatment gives your body time to recover. 

The total number of cycles will depend on your particular situation. Your treatment team will discuss this with you.

Eribulin is usually given for as long as it’s keeping the cancer under control.

Taking other medications

Tell your treatment team about any prescribed or over-the-counter medicines you’re taking, and ask their advice before taking any herbal medicines or supplements.

5. Side effects of eribulin

Like any treatment, eribulin can cause side effects. Everyone reacts differently to drugs and some people may have more side effects than others.

These side effects can usually be managed and those described here will not affect everyone.

If you’re worried about any side effects, regardless of whether they are listed here, talk to your chemotherapy nurse or treatment team as soon as possible.

Before starting chemotherapy you should be given a 24-hour contact number or told who to contact if you feel unwell at any time during your treatment, including at night or at the weekends.

Common side effects of eribulin

Effects on the blood

Eribulin can temporarily affect the number of blood cells in the body.

You’ll have regular blood tests to check your blood count. Blood is made up of red cells, white cells and platelets.

If the number of blood cells is too low, your next cycle of treatment may be delayed or the dose of chemotherapy reduced.

Risk of infection

Not having enough white blood cells can increase the risk of getting an infection.

Signs of an infection

Your treatment team may give you guidelines to follow for reporting signs of an infection. But generally you should contact your hospital immediately if you experience any of the following:  

  • A high temperature (over 37.5°C) or low temperature (under 36°C), or whatever your treatment team has advised  
  • Suddenly feeling unwell, even with a normal temperature  
  • Symptoms of an infection, for example a sore throat, a cough, a need to pass urine frequently or feeling cold or shivery 

Sometimes your doctor may recommend injections of drugs called growth factors. This helps the body produce more white blood cells to reduce your risk of infection.


Having too few red blood cells is called anaemia. If you feel particularly tired, breathless or dizzy, let your treatment team know.

Bruising and bleeding

Eribulin can reduce the number of platelets, which help the blood to clot. You may also bruise more easily, have nosebleeds or your gums may bleed when you brush your teeth. Tell your treatment team if you have any of these symptoms.

Hair loss

Many people will experience hair loss or hair thinning, including eyebrows, eyelashes and body hair.

Scalp cooling may prevent or lessen hair loss. Not all hospitals offer scalp cooling so ask your treatment team or chemotherapy nurse if this treatment is available and suitable for you.

Read more about hair loss, scalp cooling and looking after your hair.

Cancer-related fatigue (extreme tiredness)

Cancer-related fatigue is extreme tiredness that doesn’t go away with rest or sleep. It’s a very common side effect of breast cancer treatment and may affect you physically and emotionally.

It has many causes, from psychological factors such as stress of coping with the diagnosis, to physical ones such as the side effects of treatment or progression (growth and spread) of the cancer.

If you think you have fatigue, tell your GP or treatment team so you can be fully assessed and offered advice on how to manage your energy levels.

Find out more about managing fatigue.


If you were diagnosed with locally advanced or secondary breast cancer before you started or completed a family, you may be concerned about your fertility (ability to get pregnant).

Depending on your diagnosis and treatment, you may be advised not to get pregnant.

If having children of your own is important to you, and you wish to find out about possible fertility preservation options, you can discuss this with your treatment team before starting treatment.

Nausea and vomiting

You may feel sick (nausea) but most people will not actually vomit (be sick).

You’ll be given anti-sickness medication into your vein or as a tablet before the chemotherapy is given, and you’ll be prescribed anti-sickness drugs to take home to reduce nausea or stop it happening.

If you still experience nausea or vomiting, contact your treatment team as they can recommend an alternative anti-sickness drug and change your prescription for next time.

Diarrhoea or constipation

Contact your chemotherapy team if you have 4 or more episodes of diarrhoea within a 24-hour period, or you’re constipated for more than 2 to 3 days.

Joint or muscle pain

Sometimes joint, jaw or muscle pain may occur. Let your treatment team know if this happens. They can prescribe medication for pain relief.


Eribulin may cause headaches. Your treatment team can tell you how to manage these or prescribe pain relief to help.

Effects on the lungs

Eribulin can affect the way the lungs work. This is usually mild but let your treatment team know if you experience symptoms such as a cough, breathlessness or wheezing, or if any existing breathing problems get worse.

Numbness and tingling in the hands or feet (peripheral neuropathy)

You may have numbness or tingling in your hands and feet and have difficulty with tasks like doing up buttons, or being able to feel the difference between hot and cold water.

This is due to the effect the drug has on the nerves and is known as peripheral neuropathy.

In most cases it’s mild and goes away soon after treatment stops, although in some cases it can be permanent.

If it’s severe, it may be necessary to reduce the dose of eribulin or to stop it completely.

If you have tingling or numbness tell your treatment team so they can monitor your symptoms.

Hand-foot syndrome (palmar-plantar syndrome)

Some people develop soreness, redness and peeling of the palms of the hands and soles of the feet. This is known as hand-foot syndrome, and may cause tingling, numbness, pain and dryness.

Keeping the feet and hands clean, dry and well moisturised can help.

Low levels of calcium

Eribulin can cause the calcium levels in the blood to drop too low. This is known as hypocalcaemia.

Early symptoms include tingling around the mouth and lips and in the hands and feet.

You will have regular blood tests to check your levels of calcium.

Indigestion and heartburn

If you experience indigestion or heartburn, it can usually be treated with medication from your treatment team or GP.

Heart changes

Eribulin can affect the way your heart works and may not be suitable for people with existing heart conditions.

You may have a heart (cardiac) function test called an to see if your heart is working normally both before and during your treatment.

If you experience palpitations - your heart feels like it's pounding, fluttering or beating irregularly - or chest pain, tell your treatment team.

Menopausal symptoms

For women who haven’t been through the menopause, eribulin can cause menopausal symptoms. This is because it affects the ovaries, which produce oestrogen.

Common menopausal symptoms can include:

  • Hot flushes
  • Night sweats
  • Mood changes
  • Joint aches and pains
  • Vaginal dryness

You can talk to your breast care nurse or treatment team about the ways of coping with any of these symptoms.

Skin and nail changes

Skin rashes can develop, which may itch. Your treatment team can prescribe medication to help with this.

Your nails may also become brittle, discoloured or ridged and break easily. These effects usually improve after treatment has stopped.

Liver changes

Eribulin can affect how well your liver works. You’ll have regular blood tests to monitor this throughout your treatment.

This is a temporary effect and the liver usually returns to normal soon after your treatment has stopped.

But it’s important to let your treatment team know if you have had any liver problems in the past caused by hepatitis or excess alcohol use.

Abdominal pain

You may experience abdominal pain or discomfort or feel bloated. Let your treatment team or GP know so they can prescribe medication to help.

Eye problems

Eribulin can cause eyesight changes such as blurred vision. It can also make your eyes sore, itchy, dry and cause an infection.

Contact your GP or treatment team as soon as possible if you have any of these symptoms.

Less common side effects of eribulin

Sore mouth and taste changes

Looking after your mouth, including your teeth and gums, is very important during treatment.

You’ll be given mouthwash to try to reduce soreness, and to try to stop mouth ulcers developing.

It’s advisable to see your dentist for a dental check-up before chemotherapy begins and to avoid dental treatment during chemotherapy if possible.

If you do need to have dental treatment during chemotherapy, talk with your oncologist about the best time to have this.

Eribulin can make some food taste different, for example more salty, bitter or metallic. This usually returns to normal once you have finished treatment, although this may take some time.

Our information on diet during breast cancer includes tips on dealing with taste changes.

Effect on the kidneys

Occasionally urine tests can show an increase of protein or blood in the urine, but this is not likely to cause you any problems.

Driving and using machinery

Eribulin can make you feel sleepy, and may affect your ability to drive or operate machinery safely.

Avoid driving or using machinery until you are sure eribulin does not make you feel sleepy.

Rare side effects

Allergic reaction

If you have an allergic reaction to eribulin, it will probably happen within the first few minutes of your treatment and is most likely the first or second time you have the drug.

Reactions can vary from mild to severe, but severe reactions are uncommon.

You’ll be monitored closely so that any reaction can be dealt with immediately.

Symptoms of an allergic reaction include:

  • Flushing
  • Skin rash
  • Itching
  • Back pain
  • Lip or tongue swelling
  • Shortness of breath
  • Faintness
  • Fever or chills

If you have a severe reaction, treatment will be stopped immediately.

Medication can be given before future treatments to reduce the risk of further reactions.

6. Blood clots

People with breast cancer have a higher risk of blood clots. Their risk is higher because of the cancer itself and some treatments for breast cancer.

If the cancer has spread to other parts of the body (secondary breast cancer), this also increases the risk.

Having eribulin increases the risk of blood clots such as a deep vein thrombosis (DVT).

People with a DVT are at risk of developing a pulmonary embolism (PE). This is when part of the blood clot breaks away and travels to the lung.

Blood clots can be harmful but are treatable so it’s important to report symptoms as soon as possible.

Blood clot symptoms

If you have any of the following symptoms, contact your treatment team or go to your local A&E department immediately:

  • Pain, redness/discolouration, heat and swelling of the arm or leg
  • Swelling, redness or tenderness where a central line is inserted to give chemotherapy - for example in the arm, chest area or up into the neck
  • Shortness of breath
  • Pain or tightness in the chest
  • Unexplained cough or coughing up blood

Find out more about blood clots.

7. Sex, contraception and pregnancy

You’re advised not to get pregnant while having treatment because eribulin can harm a developing baby.

If you haven’t been through the menopause, talk to your team about the most suitable method of contraception for you.

It’s still possible to become pregnant even if your periods become irregular or stop.

Men receiving eribulin should not father a child during treatment.

You can still have sex during treatment. It’s thought that chemotherapy drugs can’t pass into vaginal fluids or semen. But this can’t be completely ruled out as chemotherapy drugs can pass into the blood and some other body fluids.

Most hospital specialists will advise using barrier methods of contraception, such as condoms during treatment, and for a few days after chemotherapy is given. 

Both men and women having eribulin should continue to use contraception for at least three months after having had their last dose of eribulin.

Find out more about how breast cancer and its treatment can affect sex and intimacy and read our tips on how to manage these changes.

You’ll be advised not to breastfeed during treatment with eribulin. This is because there is a chance that your baby may absorb the drug through your breast milk, which can cause harm.

8. Travel and vaccinations

If you’re planning a holiday or need to travel overseas, check with your treatment team first.

You shouldn’t have any live vaccines while you’re having chemotherapy. Live vaccines include mumps, measles, rubella (German measles), polio, BCG (tuberculosis), shingles and yellow fever.

Live vaccines contain a small amount of live virus or bacteria. If you have a weakened immune system, which you may do during chemotherapy, they could be harmful.

It’s safe to have these vaccines 6 months after your treatment finishes. Talk to your GP or treatment team before having any vaccinations.

If anyone you have close contact with needs to have a live vaccine speak to your treatment team or GP. They can advise what precautions you may need to take depending on the vaccination.

Coronavirus (Covid-19) vaccination

People having chemotherapy are advised to speak to their treatment team before having the coronavirus (Covid-19) vaccination.

Flu vaccination

Anyone at risk of a weakened immune system, and therefore more prone to infection, should have the flu vaccine.

This includes people due to have, or already having, chemotherapy. The flu vaccine is not a live vaccine so doesn’t contain any active viruses.

Talk to your chemotherapy team or breast care nurse about the best time to have your flu jab.

9. Further support

On our online forum, you can find people going through treatment at the same time as you.

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Quality assurance

Last reviewed in December 2020. The next planned review begins in February 2023.

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