Eribulin mesylate (Halaven) | Cancer Research UK
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What eribulin is

Eribulin is a chemotherapy drug that is a treatment for advanced breast cancer. It is usually used for people who have already had at least two other courses of chemotherapy. Researchers are also looking at eribulin in trials for other cancer types.

Eribulin is also called Halaven and its full name is eribulin mesylate. It was originally developed from a sea sponge called Halichondria okadai but is now made in the laboratory.


How eribulin works

Eribulin works by stopping (inhibiting) the cancer cells from separating into two new cells. So it blocks the growth of the cancer. It is a type of drug called a microtubule inhibitor.


How you have eribulin

You have eribulin into your bloodstream (intravenously). You can have it through a thin, short tube (a cannula) put into a vein in your arm each time you have treatment. Or you may have it through a central line, a portacath, or a PICC line. These are long, plastic tubes that give the drugs directly into a large vein in your chest. You have the tube put in before or during your course of treatment and it stays in place as long as you need it.

You can read our information about having chemotherapy into a vein.

You usually have eribulin treatment in a 3 week cycle. 

  • You have eribulin on the first day
  • You have a second dose one week later
  • You then have no treatment for 13 days

Your next cycle of treatment starts 3 weeks after the first dose of eribulin. 


Tests during treatment

You have blood tests before starting treatment and regularly during your treatment. The tests check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.


About side effects

We've listed the side effects associated with eribulin. You can use the links to find out more about each side effect. Where there is no link, please go to our information about cancer drug side effects or use the search box at the top of the page.

You may have a few side effects. They may be mild or more severe. A side effect may get better or worse through your course of treatment. Or more side effects may develop as the course goes on. This depends on

  • How many times you've had the drug before
  • Your general health
  • The amount of the drug you have (the dose)

The side effects may be different if you are having eribulin with other medicines.

Tell your doctor or nurse straight away if any of the side effects get severe.


Common side effects

More than 10 in every 100 people have one or more of the side effects listed below.

  • Increased risk of getting an infection from a drop in white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, a sore throat, pain passing urine, or you may feel cold and shivery. If you have a severe infection this can be life threatening. Contact your treatment centre straight away if you have any of these effects or if your temperature goes above 38°C
  • Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
  • Tiredness (fatigue) and muscle weakness during and after treatment occurs in 5 out of 10 people (50%)
  • Hair thinning happens in about 5 out of 10 people (50%) but hair grows back once the treatment ends
  • Loss of appetite
  • Numbness or tingling in fingers and toes affects just over 3 out of 10 people (30%). It can cause difficulty with fiddly things such as doing up buttons. This begins within a few days or weeks of starting treatment. Your doctor may suggest you have a reduced dose of eribulin or stop treatment for a while
  • Feeling or being sick occurs in about 3 out of every 10 people (30%). This is usually well controlled with anti sickness medicines
  • Constipation happens in more than 2 out of 10 people (20%). Your doctor or nurse may give you laxatives to help prevent this. Tell them if you are constipated for more than 3 days
  • Aching muscles and joints
  • Diarrhoea affects about 2 out of 10 people (20%). Drink plenty of fluids and tell your doctor or nurse if diarrhoea becomes severe, or continues for more than 3 days
  • Headaches
  • Temperature, chills and flu like symptoms
  • Women may stop having periods (amenorrhoea) but this may be temporary

Occasional side effects

Between 1 and 10 in every 100 people have one or more of these effects.

  • A sore or dry mouth
  • Some people develop soreness, redness and peeling of the palms of the hands and soles of the feet called hand-foot syndrome. This may cause tingling, numbness, pain and dryness
  • Vertigo or dizziness – don't drive or operate machinery if you feel dizzy
  • Bruising more easily due to a drop in platelets – you may have nosebleeds, or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs (known as petechiae)
  • Indigestion or heart burn
  • Abdominal (tummy) pain
  • Weight loss
  • Eye problems including blurred vision, sore, itchy, dry eyes, or infection – eye drops can help
  • Low levels of potassium in your blood (hypokalaemia) – let your doctor or nurse know if you have cramping in your arm or leg muscles, or tingling and numbness. Also tell them if you have palpitations (a feeling of your heart beating) or if you feel faint
  • Changes in blood sugar levels – you will have regular blood tests to check this. If you are diabetic you may need to adjust your diabetic medicines 
  • Taste changes
  • Sleep problems
  • A faster heart rate and skin flushing
  • A skin rash, or dry red skin, or nail changes
  • Liver changes that are very mild and unlikely to cause symptoms – the liver will almost certainly go back to normal when treatment finishes
  • Shortness of breath and a cough
  • Sadness or depression
  • Sweating more than usual, including at night

Rare side effects

Fewer than 1 in 100 people have these effects.

  • Shingles or cold sores
  • Ringing in the ears (tinnitus) – tell your doctor or nurse if you have this
  • Blood clots in the leg or lung – tell your doctor or nurse straight away if you have a red, hot or swollen leg or if you have sudden chest pain and breathlessness
  • High levels of bilirubin in the blood
  • Kidney changes that are mild and unlikely to cause symptoms – they will usually go back to normal when treatment ends
  • Pain when passing urine – drink plenty of fluids and let your doctor or nurse know if you have this

Important points to remember

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them. They can give you advice or reassure you. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Other medicines and supplements

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and over the counter remedies. Some drugs can react together.


This drug may harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment and for at least 3 months afterwards. Talk to your doctor or nurse about effective contraception before starting treatment.


Don't breastfeed during this treatment because the drug may come through in the breast milk.


Eribulin contains small amounts of alcohol. This is not harmful to most people but may be a problem if you have alcoholism.


Immunisations and chemotherapy

You should not have immunisations with live vaccines while you are having chemotherapy or for at least 6 months afterwards. In the UK, these include rubella, mumps, measles (usually given together as MMR), BCG, yellow fever and Zostavax (shingles vaccine).

You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered from your chemotherapy. It is safe to have the flu vaccine.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with vaccines you take by mouth (oral vaccines), but not many people in the UK have these now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.


Related information

On this website you can read about 


Breast cancer


More information on eribulin mesylate

This page does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information look at the Electronic Medicines Compendium website at

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at

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Updated: 6 October 2015