What is erythropoietin?
Erythropoietin is a type of protein that occurs naturally in the body. It can also be made as a medicine. It stimulates the bone marrow to make red blood cells.
Erythropoietin can be given as a treatment for a low red blood cell count (anaemia), as an alternative to a blood transfusion. Our red blood cells contain haemoglobin, which carries oxygen around the body. If your haemoglobin level falls too low after treatment with certain types of chemotherapy or radiotherapy, your doctor may recommend a course of erythropoietin.
There are two types of erythropoietin that work in similar ways. These are:
- epoetin (Eprex®, NeoRecormon®)
- darbepoetin (Aranesp®).
Why it is given
One of the main side effects of chemotherapy is to slow down the production of blood cells by the bone marrow. At first, only white blood cells seem to be affected. This is because red blood cells live much longer in the circulating blood. Therefore it takes longer for the effects of the chemotherapy on red blood cell production to show up in the blood.
Towards the end of your treatment, particularly if you have had a lot of chemotherapy, your red blood cell count may fall. If you have too few red blood cells (anaemia), you will feel very tiredbreathless. and may also be
If you are anaemic, you will usually be treated with a blood transfusion. Erythropoietin is sometimes given as an alternative to a blood transfusion. It will help your red blood cell count to increase and can relieve the symptoms of anaemia. It takes about 2–3 weeks for the treatment to begin to raise your red blood cell level. You will have regular blood tests while you are having treatment with erythropoietin, to make sure that your red blood cell levels stay within a normal range.
What it looks like
Erythropoietin is a colourless fluid in a small glass bottle or a pre-filled syringe.
How it is given
Erythropoietin is normally given by an injection under the skin (subcutaneously), most often in the thigh or abdomen. It can be given from once a day, to one injection every three weeks, depending on the type of erythropoietin used and on advice from your doctor. You, or a person caring for you, can be taught how to give the injections so that you can continue the treatment at home, or it may be given by a district nurse or GP practice nurse.
Possible side effects
The amount of erythropoietin that occurs naturally in the body is very small. When erythropoietin injections are given, the amount in the body increases greatly. For this reason it causes side effects, even though it is a naturally occurring substance. The side effects are not usually severe however. People react to drugs in different ways, so it is not possible to predict who is going to have side effects or which they will have. The most common side effects are listed below.
If you notice any effects which you think may be due to the drug, but which are not listed here, please discuss them with your doctor or nurse.
Flu-like symptoms Some people have flu-like symptoms, such as joint pains, weakness, dizziness and tiredness. These are more likely to occur at the start of your treatment. Your doctor may prescribe a painkiller, such as paracetamol, to help with these symptoms.
Headaches Some people may develop severe headaches, although this is rare. Let your nurse or doctor know if you develop this side effect.
High blood pressure can occur Your doctor will closely monitor your blood pressure while you are receiving erythropoietin. Let your doctor know if you take medication for high blood pressure.
Skin irritation may occur at the injection site This can be reduced by giving the injection in different places.
Skin rash You may develop a skin rash, which may be itchy.
Let your doctor or nurse know if you have any side effects.
Length of treatment
Erythropoietin can be given before anaemia develops to help prevent it occurring, or it can be started as soon as your anaemia has been diagnosed. The injections usually continue until one month after your chemotherapy course has finished, or until you are no longer anaemic.
Additional information
- You may be given iron tablets or injections to help with production of new red blood cells.
- Your erythropoietin should be stored in the fridge.
A number of trials have looked at the benefits of using erythropoietin in the treatment of people with different types of cancer. The results from some of these trials have raised questions about its safety, and have suggested that sometimes erythropoietin may cause the cancer to grow in size. There is also concern that erythropoietin might increase the risk of developing a blood clot (thrombosis). These results are being reviewed by the drug safety authorities. In the meantime there is no doubt that some people with cancer will definitely benefit from having erythropoietin, but the benefits and risks of their use should be carefully considered for each individual person.
References
This section has been compiled using information from a number of reliable sources including:
- Martindale: The Complete Drug Reference (35th edition). Sweetman et al. Pharmaceutical Press, 2007.
- British National Formulary (54th edition). British Medical Association and Royal Pharmaceutical Society of Great Britain, September 2007.
For further references, please see the general bibliography.
Via: http://www.cancerbackup.org.uk
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