What is G-CSF?
G-CSF (granulocyte-colony stimulating factor) is an haematopoietic growth factor. It stimulates the bone marrow to produce more white blood cells. Growth factors are special proteins which are produced naturally in the body. They can also be made as a drug.
One of the main side effects of chemotherapy drugs is a reduction in the number of white blood cells. This makes your body less able to fight infection. There is a risk that you could develop a serious infection, which might have to be treated in hospital. If your number of blood cells (your blood count) is low when your next dose of chemotherapy is due, the chemotherapy may have to be postponed, or the dose lowered.
G-CSF can be given to people in this situation to stimulate the bone marrow to produce new white cells more quickly after chemotherapy. This can shorten the period during which you are at risk of developing a serious infection. G-CSF is not needed with all types of chemotherapy treatment, as the white blood cell count can often recover on its own.
G-CSF may sometimes be used before high-dose chemotherapy to make the bone marrow produce more stem cells. These extra stem cells can then be collected and given back to you after high-dose chemotherapy treatment. The stem cells then go back into the bone marrow and produce blood cells.
There are three different types of G-CSF:
- lenograstim (Granocyte®)
- filgrastim (Neupogen®)
- pegylated filgrastim (Neulasta®).
These drugs all work in similar ways. The molecules of the pegylated filgrastim have had a substance added that helps the drug to work for longer.
What it looks like
G-CSF is available as a white powder, which is then dissolved in sterile water, or a colourless fluid in a small glass bottle. It is also available in a ready-to-use pre-filled syringe.
How G-CSF is given
G-CSF is usually given as an injection under the skin (subcutaneously), most often in the thigh, arm or abdomen. You, or people caring for you, can be taught how to give these injections so that you can continue the treatment at home. Alternatively, the injections may be given by a district nurse or GP practice nurse.
How often it is given
G-CSF is usually started a few days after the chemotherapy has been given, and is given daily for up to 14 days. Pegylated filgrastim is given once with each cycle of chemotherapy. Which of the types of G-CSF you get will depend upon the chemotherapy treatment you are having. Your doctor or nurse can give you more information.
Possible side effects
When G-CSF injections are given, the amount in the body increases greatly, becoming much higher than that which occurs naturally. 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.
Bone pain Some people have discomfort or a dull ache in the bones of the back, pelvis, arms or legs. This goes away when the growth-factor injections stop. Your doctor can prescribe painkillers if needed.
Red, itchy skin Your skin may become red and itchy around the area in which the injection is given. This will disappear once the course of injections is over.
Fever, chills and fluid retention G-CSF may cause fever, chills and fluid retention. Fluid retention may lead to swelling of the ankles or breathlessness.
Nausea, vomiting and diarrhoea Occasionally you may experience nausea, vomiting and diarrhoea.
Let your doctor or nurse know if you have any side effects. Your doctor may prescribe painkillers such as paracetamol to help reduce your temperature and prevent chills.
Additional information
You will need to have the levels of white blood cells in your blood checked regularly (possibly twice a week) while you are having growth factor injections.
Filgrastim and pegylated filgrastim need to be stored in the fridge. Lenograstim can be stored at room temperature. Follow any storage instructions given by your pharmacist.
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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