filgrastim at a glance
Medicine class
Granulocyte-colony stimulating factor (G-CSF)
Main role
Raises neutrophil counts or mobilises blood-forming stem cells
Administration
Usually injected under the skin; some products can be infused into a vein by healthcare professionals
Storage
Keep refrigerated and protected from light; follow the leaflet for the dispensed product
What is filgrastim used for?
Selected UK products are licensed for:
Reducing neutropenia and febrile neutropenia associated with established cytotoxic chemotherapy, excluding specified myeloid conditions.
Reducing prolonged severe neutropenia after myeloablative treatment followed by bone-marrow transplantation.
Mobilising peripheral blood progenitor cells for collection.
Managing severe congenital, cyclic or idiopathic neutropenia in people with severe or recurrent infections.
Treating persistent neutropenia in advanced HIV infection when other management options are inappropriate.
How does filgrastim work?
Filgrastim acts like human G-CSF, binding to receptors on bone-marrow precursor cells. This increases the production and release of functional neutrophils and can move blood-forming progenitor cells into the circulation for collection.
filgrastim preparations and strengths
Injection
Route: Parenteral
Strengths: 0.3 mg/mL
How to take filgrastim
Use filgrastim only as instructed by the specialist team. Self-injection should begin only after practical training and may not suit every indication or formulation.
Use the injection technique and sites demonstrated by the nurse or pharmacist.
Check that the solution meets the product leaflet's appearance requirements.
Keep syringes in their original carton in the refrigerator, protected from light.
Put used syringes directly into the supplied sharps container, not household waste.
Intravenous preparation, dilution and administration are healthcare-professional tasks.
filgrastim side effects
Common or expected effects
- Bone, muscle, joint or back pain
- Headache
- Nausea or vomiting
- Fever
- Tiredness
- Blood-count changes, including anaemia or reduced platelets
Get urgent medical advice
- Severe allergic reaction, including facial swelling, wheezing, breathlessness or collapse
- Left upper abdominal or shoulder-tip pain suggesting an enlarged or ruptured spleen
- Cough, fever and breathlessness suggesting serious lung inflammation
- Rapid swelling, low blood pressure, breathlessness or reduced urine suggesting capillary leak syndrome
- Blood or dark-brown urine, facial or ankle swelling, or reduced urine suggesting kidney inflammation
- Sickle-cell crisis in someone with sickle-cell disease or trait
filgrastim in pregnancy
Human pregnancy information is limited, and the selected UK product information does not recommend filgrastim during pregnancy. Discuss pregnancy, plans for pregnancy or becoming pregnant during treatment with the specialist prescriber.
filgrastim while breastfeeding
It is unknown whether filgrastim or its metabolites enter human milk, so risk to a breastfed child cannot be excluded. The specialist team should weigh the benefit of breastfeeding against the clinical need for filgrastim before deciding whether either should be paused.
filgrastim interactions
Tell the specialist team about all prescribed, non-prescription and complementary products. Relevant considerations include:
Myelosuppressive cytotoxic chemotherapy
Administration must be coordinated by the oncology team because giving filgrastim too close to chemotherapy may expose rapidly dividing marrow cells to cytotoxic treatment.
Fluorouracil
Limited evidence suggests concurrent use may worsen neutropenia.
Common questions about filgrastim
Answers are fully visible for fast scanning and source review.
Why is filgrastim given after chemotherapy?
Chemotherapy can suppress bone marrow and lower neutrophil counts. Filgrastim stimulates neutrophil production, helping reduce treatment-related neutropenia in licensed settings.
Does filgrastim treat an infection?
No. It supports neutrophil production but is not an antibiotic. Fever or other infection symptoms still require prompt assessment by the treating team.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.