Granulocyte colony stimulating factor (G-CSF)

G-CSF is a type of growth factor. You might have G-CSF after chemotherapy to help your white blood cells recover after treatment. Or you might have it before and after a stem cell transplant.

There are different types of G-CSF, including:

  • lenograstim (Granocyte)
  • filgrastim (Neupogen, Zarzio, Nivestim, Accofil)
  • long acting (pegylated) filgrastim (pegfilgrastim, Neulasta, Pelmeg, Ziextenco) and lipegfilgrastim (Lonquex)

Pegylated G-CSF stays in the body for longer so you have treatment less often than with the other types of G-CSF. This type of G-CSF is not commonly used in the NHS. 

How G-CSF works

Growth factors are proteins made in the body. Some of them make the bone marrow produce blood cells. G-CSF is a type of growth factor that makes the bone marrow produce more white blood cells so it can reduce the risk of infection after some types of cancer treatment.

G-CSF also makes some stem cells move from the bone marrow into the blood. Stem cells are very early cells that develop into red blood cells, white cells and platelets.

Before a stem cell transplant, you have G-CSF to stimulate the bone marrow to produce stem cells and release them into the blood. The stem cells are collected and then you have high dose chemotherapy.

The high dose of chemotherapy stops your bone marrow producing blood cells. So you have the stem cells infused back into your bloodstream. They go into the bone marrow and start making the different types of blood cells again. 

How you have it

Most people have G-CSF as an injection under the skin. You can also have it as a drip into your bloodstream (intravenously).  

Injection under your skin

You usually have injections under the skin (subcutaneous injection) into the stomach, thigh or top of your arm.

You might have stinging or a dull ache for a short time after this type of injection but they don't usually hurt much. The skin in the area may go red and itchy for a while.

The video below shows you how to give an injection just under your skin (subcutaneously). 

Into your bloodstream

You might have treatment through a long plastic tube that goes into a large vein in your chest. The tube stays in place throughout the course of treatment. This can be a:

  • central line
  • PICC line
  • portacath

If you don't have a central line

You might have treatment through a thin short tube (a cannula) that goes into a vein in your arm. You have a new cannula each time you have treatment.


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

Side effects

How often and how severe the side effects are can vary from person to person. They also depend on what other treatment you are having. 

When to contact your team

Your doctor, nurse, or pharmacist will go through the possible side effects. They will monitor you closely during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

  • you have severe side effects 
  • your side effects aren’t getting any better
  • your side effects are getting worse
Early treatment can help manage side effects better.

We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.

You usually have G-CSF after chemotherapy, so it’s not always clear if the side effect are caused by G-CSF or chemotherapy.

The side effects listed below are for the G-CSF drug filgrastim.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10 %). You might have one or more of them. They include:

Bone or muscle pain 

You might experience pain in your bones or muscles. Speak to your doctor as they can prescribe medicine to help. 


Tell your healthcare team if you keep getting headaches. They can give you painkillers to help.

Tiredness and weakness (fatigue)

Tiredness and weakness (fatigue) can happen during and after treatment. Doing gentle exercises each day can keep your energy up. Don't push yourself, rest when you start to feel tired and ask others for help.

Bruising, bleeding gums or nosebleeds

This is due to a drop in the number of platelets in your blood. These blood cells help the blood to clot when we cut ourselves. 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).


Contact your advice line if you have diarrhoea, such as if you've had 4 or more loose watery poos (stools) in 24 hours. Or if you can't drink to replace the lost fluid. Or if it carries on for more than 3 days.

Your doctor may give you anti diarrhoea medicine to take home with you after treatment. Eat less fibre, avoid raw fruits, fruit juice, cereals and vegetables, and drink plenty to replace the fluid lost.

Feeling or being sick

Feeling or being sick is usually well controlled with anti sickness medicines. Avoiding fatty or fried foods, eating small meals and snacks, drinking plenty of water, and relaxation techniques can all help.

It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treating it once it has started.

High temperature (fever)

If you get a high temperature, let your healthcare team know straight away. Ask them if you can take paracetamol to help lower your temperature.

Breathlessness and looking pale

You might be breathless and look pale due to a drop in red blood cells. This is called anaemia.

Hair thinning

Your hair may thin but you’re unlikely to lose all your hair. This usually starts after your first or second cycle of treatment. It is almost always temporary and your hair will grow back when you finish your treatment.

Sore mouth, throat, gut and back passage

It may be painful to swallow drinks or food . Or you might also have diarrhoea and pain if your bowel is inflammed.This can be caused by inflammation of the mucosa (thin lining of the internal organs).

Painkillers can help to reduce the soreness. And mouth washes can help keep your mouth healthy. There might also be numbing gel you could use for your back passage when having a poo.

Let your healthcare team know if you notice any of these symptoms.

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

  • enlarged spleen and liver - this might cause tummy (abdominal) pain
  • swollen hands and feet (oedema)
  • reddening of the skin and rash. Rarely the rash might be bumpy. Tell your team if this happens, they might be able to give you some medicine to help.
  • constipation
  • difficulty sleeping (insomnia)
  • breathlessness and cough - rarely this could be due to scarring, stiffening or inflammation of the lungs, or a drop in the levels of oxygen in the blood
  • pain or difficulty passing urine
  • increased risk of getting an infection
  • loss of appetite
  • tingling or numbness of the hands or feet (paraesthesia) loss of feeling of sensitivity, especially in the skin (hypoaesthesia)
  • high levels of an enzyme in your blood that can be a sign of injury to your body’s tissues – you have regular blood tests to check this
  • high or low blood pressure – you might have headaches or feel faint
  • muscle spasms
  • generally feeling unwell
  • chest pain
  • pain
  • a reaction during the infusion – you might get a rash, shortness of breath, redness or swelling of the face and dizziness – tell your team straight away

Rare side effects

This side effects happens in fewer than 1 in 100 people (fewer than 1%). You might have one or more of them. They include:

  • high number of white blood cells in the blood
  • an allergic reaction that can cause a rash, shortness of breath, redness or swelling of the face and dizziness - some allergic reactions can be life-threatening alert your nurse or doctor if notice any of these symptoms
  • rejection of transplanted bone marrow (graft versus host disease)
  • leaking of fluid and proteins out of the blood vessels into the tissues (capillary leak syndrome)
  • high uric acid levels in the blood that may cause gout – you have regular blood tests to check this
  • blockages of the small veins in the liver causing liver damage
  • inflammation around the drip site
  • changes in your lungs as seen on an x-ray
  • high levels of enzymes in the blood that could be a sign of liver damage – you have regular blood tests to check this
  • thinning of the bones which can make the bones weaker and easier to break (osteoporosis)
  • small amounts of protein found in your urine
  • severe pain in the bones, chest, gut or joints (sickle cell anaemia with crisis)
  • plum coloured, raised, painful sores on the your legs or arms and sometimes the face and neck with a high temperature (Sweets syndrome)

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do I need to know?

Latex allergy

The needle cover of some of the syringes are made from a natural rubber called latex. If you have an allergy to latex this might cause you to have an allergic reaction. Please let your healthcare team know if you have a latex allergy.

Other medicines, foods and drink 

Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.


This drug contains a type of sugar called sorbitol. If you have an intolerance to some sugars, ask your doctor if it is safe for you to take this drug.

Pregnancy and contraception

This treatment might harm a baby developing in the womb. It is important not to become pregnant or father a child while you're having treatment and for a few months afterwards.

Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner falls pregnant while having treatment.


It is not known whether this treatment affects fertility in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.


Don’t breastfeed during this treatment because the drug may come through into your breast milk.

Treatment for other conditions 

Always tell other doctors, nurses, pharmacists or dentists that you’re having this treatment. For example, if you need treatment for anything else, including teeth problems.

More information about this treatment

For further information about this treatment go to the electronic Medicines Compendium (eMC) website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

  • Electronic Medicines Compendium 

    Accessed July 2019

  • Neutropenic sepsis: prevention and management in people with cancer
    The National Institute for Health and Care Excellence (NICE), 2012

  • Guideline for the use of granulocyte colony stimulating factor (G-CSF) for adults in oncology and haematology
    Norfolk and Norwich University Hospitals NHS Foundation Trust, 2017

  • 2006 Update of ASCO Practice Guideline Recommendations for the Use of White Blood Cell Growth Factors: Guideline Summary
    Journal of Oncology Practice, 2006. Vol 2, number 4, pages 196-201

Last reviewed: 
28 Sep 2020
Next review due: 
28 Sep 2023

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