Some cancers and cancer treatments can affect the bone marrow, reducing your ability to make new red blood cells. This condition is called anaemia, and can make you feel tired, breathless or weak.

To help restore the number of red blood cells in your blood, your doctor may prescribe a treatment called erythropoietin. This is a protein that helps your bone marrow to make more red blood cells. Erythropoietin is only used in certain situations. Having a blood transfusion is a much more common treatment for anaemia.

Erythropoietin is given as an injection under the skin. You or your carers can be taught how to give the injections so you can have the treatment at home.

It can have some side effects, but they usually are not severe and won’t affect everyone having the treatment. Your doctor will discuss with you whether erythropoietin is a suitable treatment for you.

How erythropoietin works

Erythropoietin is a type of protein called a growth factor. There are different types; epoetin alfa, beta, zeta, theta (Eprex®, NeoRecormon®) and darbepoetin alfa (Aranesp®). People often call them EPO for short.

It stimulates the bone marrow to make red blood cells. The bone marrow is a spongy material inside the bones where all of our blood cells are made.

Erythropoietin is made naturally in the body. But it can be made outside the body and used as a treatment for anaemia. Anaemia means having too few red blood cells.

Red blood cells carry oxygen around the body. If the number of red blood cells in your blood is low, you may be very tired and feel you have no energy. You may also become breathless.

Many people with cancer will develop anaemia at some time during their illness. Anaemia can also be caused by treatment with chemotherapy. Doctors sometimes use erythropoietin to treat anaemia instead of giving you a blood transfusion or if you cannot have a blood transfusion.

There are certain cancers that erythropoietin may not be safe to use in, for example, head and neck or breast cancer. You can ask your doctor whether it may be helpful for you.

How erythropoietin is given

You usually have erythropoietin as an injection under the skin (subcutaneously) in the thigh or tummy. A nurse can teach you, or a person caring for you, to give the injections. Or a district nurse or practice nurse may give you the injections.

Your doctor may give you iron as tablets or injections during your treatment to help your body make red blood cells. This may make erythropoietin more effective. Your doctor can tell you if this will be helpful for you.

How often you have erythropoietin will depend on the type used. It can be given three times a week, once a week or every three weeks. The injections usually continue until one month after your chemotherapy course has finished, or until you are no longer anaemic. Your doctor will explain how often you will have the injections.

Possible side effects of erythropoietin

Even though erythropoietin is a naturally-occurring substance, you may have side effects. When you're given erythropoietin injections, the amount of it in your body becomes much higher than normal. However, these side effects aren't usually severe and they do reduce after erythropoietin treatment ends.

We have included the most common side effects of erythropoietin here. We haven’t included all the less common and rarer side effects. You may get some of the side effects we mention, but you will not get them all.

If you have chemotherapy with erythropoietin, some side effects may be worse. You may also have side effects not listed here. We have more information about chemotherapy.

Your doctor can prescribe drugs to help control some side effects. It is very important to take them exactly as your nurse or pharmacist has explained. This will help the drugs work as well as possible for you.

Your nurse will give you advice about managing side effects. After your treatment is over, side effects will start to improve. Always tell your doctor or nurse about the side effects you have.

Serious and life-threatening side effects

Sometimes cancer drugs can result in very serious side effects, which rarely may be life-threatening. Your cancer doctor and nurse can explain the risk of these side effects to you.

Allergic reaction

Rarely some people have an allergic reaction to erythropoietin. Contact the hospital straight away on the number you’ve been given if you develop any of the following:

  • red, warm and itchy bumps on the skin (like nettle rash)
  • swelling of the lips, tongue or throat
  • breathlessness, wheezing, a cough or sudden difficulty breathing
  • tight chest or chest pain.

Contact the hospital

Your nurse will give you telephone numbers for the hospital. You can call them if you feel unwell or need advice any time of day or night. Save these numbers in your phone or keep them somewhere safe.

More information about this drug

We’re not able to list every side effect for this treatment here, particularly the rarer ones. For more detailed information you can visit the electronic medicines compendium (eMC).

Feeling sick or being sick

You may feel sick during treatment with erythropoietin. Your doctor can prescribe anti-sickness (anti-emetic) drugs to help prevent or control sickness. Take the drugs exactly as your nurse or pharmacist explains to you. It’s easier to prevent sickness than to treat it after it has started.


Your doctor can prescribe drugs to control diarrhoea. Let them know if it is severe or if it doesn’t get better. Make sure you drink at least two litres (three and a half pints) of fluids every day if you have diarrhoea.

Flu-like symptoms

Some people have flu-like symptoms, such as feeling sick, joint pains, weakness, dizziness and tiredness. You are more likely to have these symptoms at the start of your treatment. Usually they last for a few days. Your doctor may prescribe a painkiller, such as paracetamol, to help with these symptoms.

Risk of developing a blood clot

Cancer can increase the risk of developing a blood clot (thrombosis), and erythropoietin may increase this risk further. A clot can cause symptoms such as pain, redness and swelling in a leg, breathlessness and chest pain. Contact your doctor straight away if you have any of these symptoms. A blood clot is serious but your doctor can treat it with drugs that thin the blood. Your doctor or nurse can give you more information.

High blood pressure

Erythropoietin may cause this. Tell your doctor or nurse if you have ever had any problems with your blood pressure. You should also tell them if you take any medication for high blood pressure. Your nurse will check your blood pressure regularly during your treatment. If you have a severe headache, drowsiness, confusion, problems with your eyesight, nausea, vomiting or fits, your blood pressure may be very high. Call your doctor straight away if you have any of these symptoms.


Erythropoietin can increase the risk of having a stroke. Signs of a stroke include weakness or numbness in one side of your body, slurred speech or drooping of your face, mouth or eye. If you or someone you know notices you have any of these symptoms, you should tell a doctor immediately.

Build up of fluid

You may put on weight or your ankles and legs may swell because of fluid building up. Tell your doctor or nurse if fluid builds up. If your ankles and legs swell, it can help to put your legs up on a foot stool or cushion. The swelling gets better after your treatment ends. Skin irritation at the injection site Your skin may become red or tender in the area the injection is given. Having the injection in a different place on your body each time may help.

Skin rash

You may develop a skin rash, which may be itchy and red. Tell your doctor if you notice this. They can give you advice and may prescribe creams or medicines to help.

It's important to let your doctor know straight away if you feel unwell or have any severe side effects, even if they're not mentioned above.

Other information about erythropoietin

A number of trials have looked at the benefits of using erythropoietin to treat people with different types of cancer. The results from some of these trials have raised questions about its safety. Some have suggested that sometimes erythropoietin may cause the cancer to grow in size. These results are being reviewed by the drug safety authorities.

Although some people with cancer will benefit from having erythropoietin, your doctor will carefully consider the benefits and risks in your situation.

If you are worried or have any questions about this, talk to your doctor or specialist nurse.

Other medicines

Some medicines can interact with erythropoietin. This includes medicines you can buy in a shop or chemist. Tell your doctor about any medicines you're taking, including ones you can buy for yourself, complementary therapies, vitamins and herbal drugs.


Your doctor will advise you not to become pregnant or father a child while having erythropoietin as it may harm the developing baby. It’s important to use effective contraception while having this drug, and for at least a few months afterwards. You can discuss this with your doctor or nurse.


Women are advised not to breastfeed during treatment and for a few months afterwards. This is in case there is any of the drug in their breast milk.

Medical and dental treatment

If you need to go into hospital for a reason not related to the cancer, always tell the doctors and nurses looking after you that you are having erythropoietin treatment. You should tell them the name of your cancer specialist so they can ask for advice.

Always tell your dentist you are having treatment with erythropoietin.