How do you take Filgrastim?

This injection is usually given under the skin (like insulin) or through a drip in the hospital. Your doctor will decide the exact dose based on your body weight, typically 5 to 10 micrograms per kilogram of body weight per day. It is best administered by a healthcare professional, especially the first few times.

What are the side effects of Filgrastim?

Bone pain or body aches (very common), headache, feeling tired or weak, nausea or vomiting, pain or redness at the injection site

Who should not take Filgrastim?

People who are allergic to filgrastim or any of its ingredients. People with severe kidney or liver disease should use it with caution. It should not be used to increase white blood cells in people with certain types of blood cancers unless specifically prescribed by a specialist.

Prescription

Colony-Stimulating Factor (White Blood Cell Booster)

Filgrastim

Last reviewed July 2026

Who is this for?

For adults (18+). Standard adult dosing applies: see the How to Take tab for full instructions.

What is this drug?

Filgrastim is an injection that helps your body make more white blood cells, which are the cells that fight infections. It works by stimulating your bone marrow (where blood cells are made) to produce more of these infection-fighting cells.

How it works

Binds to granulocyte colony-stimulating factor (G-CSF) receptors on bone marrow progenitor cells, stimulating proliferation, differentiation, and activation of neutrophils to increase circulating white blood cell counts.

What is it used for?

Low white blood cell count after chemotherapy (cancer treatment), helping the body recover after bone marrow transplant, severe long-term low white blood cell conditions, boosting white blood cells in HIV/AIDS patients

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Cancer Treatment HIV & AIDS

Prescription Required

You need a doctor's prescription to buy this drug.

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What to watch out for

Only buy Filgrastim (Zarzio) from reputable hospitals or registered pharmacies, never from roadside sellers, as it must be kept cold and fake versions can be dangerous. Always ensure the injection is given by a trained healthcare worker. Attend all your follow-up blood tests so your doctor can monitor your white blood cell levels properly.

Common Side Effects

Bone pain or body aches (very common)
headache
feeling tired or weak
nausea or vomiting
pain or redness at the injection site

Serious Side Effects

Difficulty breathing or chest pain: this could mean a serious lung problem
so go to the hospital immediately. Severe pain in the upper left side of your belly: this could be a spleen problem and is a medical emergency. Sudden swelling of the face
lips
or throat with difficulty breathing: this is a severe allergic reaction
so seek help immediately.

Drug Interactions

Do not use filgrastim within 24 hours before or after chemotherapy drugs, as it can make side effects worse. Lithium (used for mental health conditions) may increase white blood cell production too much when combined with filgrastim. Always tell your doctor about every medication you are taking, including herbal remedies.

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Pregnancy & Breastfeeding Warning

Filgrastim is not recommended during pregnancy or breastfeeding unless your doctor decides the benefit is greater than the risk. Always consult your doctor.

Who Should NOT Take This

People who are allergic to filgrastim or any of its ingredients. People with severe kidney or liver disease should use it with caution. It should not be used to increase white blood cells in people with certain types of blood cancers unless specifically prescribed by a specialist.

How to Store

Store in a refrigerator (2°C to 8°C). Do not freeze. In Nigeria's hot climate, never leave it outside the fridge, as heat will spoil it. Keep it away from direct sunlight and out of reach of children. If you are transporting it, use a cold pack or cooler bag.

For information only: not medical advice. Always talk to a doctor or pharmacist before changing your medication.