Neupogen (Filgrastim) 


Receive our quarterly lifestyle research updates

Your doctor has recommended a treatment called Neupogen (filgrastim) which is used to support you and your white cells during chemotherapy. This page aims to supplement the information given to you by the clinic to help you understand why Neupogen is given and what to expect. It also gives information to the district nurse who may be giving you the injections. For more detailed information please refer to the product information within the packet or go to USA website.

What are white cells?   Blood contains three main elements. The red cells which carry oxygen around the body from the lungs, platelets which stop us bleeding when we are cut, and white cells which help our immunity and protect us from infection. There are a number of different types of white cells but one of the most important types, are called neutrophils or granulocytes. These protect us from bacteria, which are the most likely source of infection during chemotherapy.

How does chemotherapy effect your white cells? Chemotherapy affects the rapidly dividing cells within the body.  The cells (stem cells) which make white cells are found within the bone marrow, also grow fairly rapidly and hence are often damaged by chemotherapy (see chemotherapy).  Hopefully the most rapidly dividing cells of all are those within the tumour. This is one of the reasons that chemotherapy is given in cycles, to allow the white cells to recover before the next injection. Hopefully less normal cells are killed at each cycle than tumour cells and more normal cells recover than tumour cells before the next cycle.

Sometimes too many white cells are killed and patients become susceptible to infection which can to be serious. This is most likely to happen in the middle week between cycles. If, during chemotherapy, you experience shivering or shaking attacks of fever or feel hot or unwell check your temperature. If it is raised, telephone the Hospital immediately and they will advise you. Do not take Paracetamol or Aspirin as this will bring your temperature down and mask the signs of infection. 

How does Neupogen work?   Neupogen is similar to a naturally occurring protein  which stimulates the colonies of white stem cells within the bone marrow  causing the level of neutrophils in the blood to rise (Granulocyte Colony Stimulating Factor - GCSF).   Increasing the levels of neutrophils in the blood stream reduces the risk and severity of infection.

When is Neupogen used? Neupogen is not often used  at the start of the first cycle of chemotherapy as in most cases it is not necessary (primary prophylaxis). The exception is "high dose" chemotherapy (see autologous bone marrow transplantation) when it is used to raise the level of stem cells in the blood. These stem cells can be harvested and used or stored in a fridge for later use. After the chemotherapy they can be re-injected into the patient to help the bone marrow recover. Sometimes during conventional chemotherapy too many white cells are killed and the patient develops an infection which can be serious. Neupogen is sometimes used, as well as antibiotics, to treat the infection. Firstly, Neupogen can be used to support chemotherapy. If the white cells (neutrophils) will not or are unlikely to recover by the time the next chemotherapy is due, your Oncologist has three choices:

  • Delay chemotherapy
  • Reduce the dose of chemotherapy
  • Give Neupogen

By giving Neupogen, the chances of neutrophil recovery are increased. This would allow scheduled chemotherapy to be given as planned and prevent unnecessary chemotherapy delays and reductions.

Secondly, Neupogen has a role in the collection of blood stem cells (Peripheral Blood Stem Cell Transplantation). By administrating Neupogen, bone marrow stem cells are released into the bloodstream, where they can be selectively removed and stored frozen for future use. Once chemotherapy has been given, the stem cells are then re-infused back into the patient. They automatically navigate themselves back to the bone marrow and re-establish themselves as an active source of new blood cells.

Thirdly, Neupogen can be given to encourage neutrophil recovery following a Bone Marrow Transplant.

How should Neupogen be given?  Neupogen is given as an injection under the skin (subcutaneous) containing 30 or 48 million units of filgrastim in a pre-filled syringe. The ways in which it is given vary from doctor to doctor and department to department. The most common way is the day after the chemotherapy has finished every day for 7 days but this can vary from 3-10 (You may wish to write the days in the table below and show it to the district nurse). Some patients learn to inject themselves (see self injection) but in others, your chemotherapy nurse will arrange a district nurse to give it.

Chemotherapy cycle Start date of Neupogen Number of days

Side effects

Neupogen is generally well tolerated and it is often difficult to separate the mild side effects from those caused by the chemotherapy. Even so, occasional side effects can occur and these are mentioned below.  It is rarely possible to develop side effects not mentioned here.

  • It is common to have aching bones and joints for 2-3 days duration starting 1-2 days after the start of the injections. This is usually mild and is caused by the bone marrow working harder to produce more white cells. Occasionally it is more troublesome and pain killers are required. (Provided you don't have a temperature paracetamol is often helpful. If it is not strong enough ask your doctor about a slightly stronger analgesic. Remember if you feel unwell check your temperature before you due to take your next pain killers).
  • Occasionally irritation at the injection site ( remember to alternate the sites each day)
  • Rarely - Mild flu like symptom,  headache, malaise, rigors & nausea.
  • Rarely - Mild itching and occasional skin rash.

These last two symptoms are caused by a mild allergic-like reaction. They can usually be corrected next time by a small dose of oral steroids or antihistamines taken just before your Neupogen injection.

Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.

Lifestyle tips Aide gut health Micronutrient tests Protect nails
Amazing polyphenols