Generic name: filgrastim [ fil-GRA-stim ]
Other brand names of filgrastim include: Neupogen, Neupogen SingleJect, Nivestym, Nypozi, Releuko, Zarxio
Drug class: Colony stimulating factors

Medically reviewed by Drugs.com on Sep 8, 2025. Written by Cerner Multum.

What is filgrastim?

Filgrastim is used to treat neutropenia (lack of certain white blood cells) in patients receiving certain cancer medications, undergoing a bone marrow transplant, or caused by other conditions.

Filgrastim can be used in a procedure called leukapheresis, where white blood cells needed for a stem cell transplant are removed from the body.

Some brands of this medicine are also used in patients who have been exposed to a certain amount of radiation.

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

Filgrastim side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Capillary leak syndrome is a rare but serious side effect. Call your doctor right away if you have signs of this condition: stuffy or runny nose followed by tiredness, thirst, decreased urination, trouble breathing, and sudden swelling or weight gain.

Filgrastim can cause your spleen to become enlarged, and it could rupture (tear). Call your doctor right away if you have left-sided upper stomach pain or left shoulder pain.

Nypozi may cause serious side effects. Call your doctor at once if you have:

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

• stomach pain, discomfort, back pain;

• new or worsening cough or coughing up blood;

• fever with shortness of breath or rapid breathing;

• signs of sickle cell anemia crisis--pain or difficulty breathing; or

• kidney problems--swelling, urinating less, feeling tired or short of breath.

Common side effects of Nypozi may include:

• fever, pain, cough, shortness of breath;

• nosebleeds;

• anemia (low red blood cells);

• bone pain;

• diarrhea;

• headache;

• numbness; or

• rash, hair loss.

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.

Related/similar drugs

Warnings

Use only as directed. Tell your doctor if you use other medicines or have other medical conditions or allergies.

Before taking this medicine

You should not use this medicine if you are allergic to filgrastim or other granulocyte colony stimulating factor such as pegfilgrastim, tbo-filgrastim, sargramostim, or eflapegrastim.

Tell your doctor if you have or have ever had:

• sickle cell disorder;

• an allergy to latex;

• radiation treatment; or

• kidney disease.

Using filgrastim may increase your risk of developing myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) if you have certain medical conditions. Ask your doctor about this risk.

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

Ask a doctor if it is safe to breastfeed while using this medicine.

How should I use filgrastim?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Filgrastim is injected under the skin or into a vein. A healthcare provider may give you this injection or may teach you how to properly use this medicine by yourself.

Your dose needs may change if you switch to a different brand, strength, or form of this medicine. Avoid medication errors by using exactly as directed on the label, or as prescribed by your doctor.

Doses are based on weight. Your dose may change if you gain or lose weight.

Your healthcare provider will show you where to inject filgrastim. Do not inject into the same place two times in a row.

Do not inject into areas where the skin is tender, bruised, red, or hard. Avoid injecting into skin that has scars or stretch marks.

Do not change your dose or stop using a medicine without your doctor's advice.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand these instructions.

Prepare an injection only when you are ready to give it. Call your pharmacist if the medicine looks cloudy, has changed colors or has particles in it.

Your blood will need to be tested often. Your doctor will need to check your progress on a regular basis, and your next dose may change based on the results.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using filgrastim.

Store filgrastim in the original container in a refrigerator, away from light. Do not freeze and do not shake.

Do not warm the medicine with hot water, sunlight, or a microwave.

Take the medicine out of the refrigerator and let it reach room temperature for 30 minutes before using.

You may store filgrastim at room temperature for a limited period depending on the brand form. Throw away any medicine not used within that time. Talk to your pharmacist if you have any questions.

Each prefilled syringe or vial (bottle) is for one use only. Throw away after one use, even if there is still medicine left inside. Place it in a puncture-proof "sharps" container and dispose of it following state or local laws. Keep out of the reach of children and pets.

What happens if I miss a dose?

Call your doctor for instructions if you miss a 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 filgrastim?

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

What other drugs will affect filgrastim?

Do not use filgrastim within 24 hours before or after you receive chemotherapy, or within 24 hours after a bone marrow transplant.

Other drugs may affect filgrastim, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Biological Products Related to Nypozi

Find detailed information on biosimilars for this medication.

Popular FAQ

More FAQ

• What biosimilars have been approved in the United States?
• What is the difference between Nivestym and Neupogen?

Further information

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

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

Medical Disclaimer

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