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Generic name: filgrastimfil-GRAS-tim ]
Brand names: Neupogen, Neupogen SingleJect
Drug class: Colony stimulating factors

Medically reviewed by Sanjai Sinha, MD. Last updated on Apr 28, 2022.

What is Neupogen?

Neupogen is a man-made form of a protein that stimulates the growth of white blood cells in your body. White blood cells help your body fight against infection.

Neupogen is used to treat neutropenia, a lack of certain white blood cells caused by cancer, bone marrow transplant, receiving chemotherapy, or by other conditions.

Neupogen may also be used for purposes not listed in this medication guide.


Neupogen can cause your spleen to become enlarged and it could rupture (tear). Call your doctor right away if you have sudden or severe pain in your left upper stomach spreading up to your shoulder.

Before using Neupogen, tell your doctor if you have a blood cell disorder (such as sickle cell anemia), chronic myeloid leukemia, myelodysplasia (also called "preleukemia"), or if you are receiving chemotherapy or radiation treatment.

Stop using Neupogen and call your doctor at once if you have a serious side effect such as sudden or severe pain in your left upper stomach spreading up to your shoulder, rapid breathing or feeling short of breath, or signs of infection (fever, chills, sore throat, flu symptoms, easy bruising or bleeding, loss of appetite, nausea and vomiting, mouth sores, or unusual weakness).

Before taking this medicine

You should not use Neupogen if you are allergic to filgrastim or pegfilgrastim, or to other medicines that contain the E. coli bacteria.

To make sure Neupogen is safe for you, tell your doctor if you have ever had:

  • sickle cell anemia;

  • kidney disease;

  • latex allergy; or

  • radiation treatment.

It is not known whether Neupogen will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It may not be safe to breast-feed a baby while you are using filgrastim. Ask your doctor about any risks.

How should I use Neupogen?

Neupogen is injected under the skin or as an infusion into a vein. A healthcare provider will give your first dose and may teach you how to properly use the medication by yourself.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Neupogen vials and prefilled syringes do not contain the same concentrations of filgrastim. Do not give an injection unless you are trained in properly measuring your dose from either the vial or the prefilled syringe.

Read and carefully follow any Instructions for Use provided with your medicine. Do not use Neupogen if you don't understand all instructions for proper use. Ask your doctor or pharmacist if you have questions.

Prepare your injection only when you are ready to give it. Do not use if the medicine has changed colors or has particles in it. Call your pharmacist for a new supply.

You may need frequent medical tests to help your doctor determine how long to treat you with Neupogen. Your liver function will also need to be tested, and you may need bone density scans.

Store in the original container in a refrigerator. Do not freeze and do not shake.

Take the medicine out of the refrigerator and allow it to reach room temperature for 30 minutes before injecting your dose. Do not leave the medicine at room temperature for longer than 24 hours.

Each single-use vial (bottle) or prefilled syringe is for one use only. Throw it away after one use, even if there is still medicine left inside.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

What happens if I miss a dose?

Use the missed dose as soon as you remember, but not within the 24-hour period before or after you receive chemotherapy treatment. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using Neupogen?

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Neupogen side effects

Get emergency medical help if you have signs of an allergic reaction to Neupogen: hives, sweating; dizziness, fast heart rate; wheezing, difficult breathing; swelling of your face, lips, tongue, or throat.

Neupogen can cause your spleen to become enlarged and it could rupture (tear). Call your doctor right away if you have sudden or severe pain in your left upper stomach spreading up to your shoulder.

Stop using Neupogen and call your doctor at once if you have:

  • easy bruising, unusual bleeding, purple or red spots under your skin;

  • fever, tiredness, stomach pain, back pain;

  • rapid breathing, feeling short of breath, pain while breathing;

  • capillary leak syndrome - sudden dizziness or light-headed feeling, tiredness, trouble breathing, swelling or puffiness and feeling full;

  • kidney problems - little or no urinating, blood in your urine, swelling in your face or ankles;

  • low red blood cells (anemia) - pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands and feet; or

  • signs of infection - fever, chills, sore throat, flu symptoms, loss of appetite, nausea and vomiting, mouth sores, unusual weakness.

Common Neupogen side effects may include:

  • fever, cough, trouble breathing;

  • nosebleeds;

  • bone pain, muscle or joint pain;

  • diarrhea;

  • headache;

  • numbness; or

  • rash, thinning hair.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Neupogen?

If you also receive chemotherapy or a bone marrow transplant: Do not use Neupogen within 24 hours before or 24 hours after you receive chemotherapy, or within 24 hours after a bone marrow transplant.

Other drugs may interact with filgrastim, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Frequently asked questions

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Neupogen only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.