[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Myeloid colony-stimulating factors](https://durgical.com/en/pharmacology/classes/myeloid-colony-stimulating-factors/) › Filgrastim

[Pharmacology](https://durgical.com/en/pharmacology/) · [Myeloid colony-stimulating factors](https://durgical.com/en/pharmacology/classes/myeloid-colony-stimulating-factors/)

# Filgrastim

Recombinant G-CSF that raises neutrophils and shortens neutropenia after chemotherapy, in transplants and in severe chronic neutropenia.

Updated 2026-11-01

- Class: [Myeloid colony-stimulating factors](https://durgical.com/en/pharmacology/classes/myeloid-colony-stimulating-factors/)
- Receptor: Granulocyte colony-stimulating factor receptor (G-CSFR)
- ATC code: L03AA02
- WHO Model List of Essential Medicines

Also called: recombinant granulocyte colony-stimulating factor (G-CSF)

◎**Granulocyte colony-stimulating factor receptor (G-CSFR)**Filgrastim

ⓘ The figure shows human G-CSF (the same protein as filgrastim, which is made in bacteria) bound to its receptor.

**Target in 3D:** Granulocyte colony-stimulating factor receptor (G-CSFR). PDB structure 2D9Q (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/2D9Q) · Drag to rotate · pinch to zoom

## Mechanism of action

Filgrastim is human granulocyte colony-stimulating factor produced in Escherichia coli. It binds the G-CSF receptor on neutrophil progenitors, increasing their production, maturation and release from the marrow, and enhances the function of mature neutrophils.

- The drug binds the G-CSF receptor on myeloid progenitors
- JAK–STAT signalling drives neutrophil production and maturation
- Neutrophils are released sooner from the marrow
- Neutropenia is shorter, so fewer infections

## Pharmacokinetics

**Absorption**
Subcutaneous or intravenous

**Elimination**
Shorter-acting than pegfilgrastim, so it is given daily

## Indications

- Prevention of febrile neutropenia after myelosuppressive chemotherapy [Febrile neutropenia →](https://durgical.com/en/conditions/febrile-neutropenia/)
- Severe chronic neutropenia [Neutropenia and drug-induced agranulocytosis →](https://durgical.com/en/conditions/neutropenia-and-drug-induced-agranulocytosis/)
- After bone marrow transplantation, and to mobilise stem cells for collection

## Adverse effects

### Common

- Bone, back and limb pain
- Injection-site redness or swelling
- Headache, rash

### Serious (rare, important)

- Splenic rupture: left upper abdominal or left shoulder-tip pain
- Acute respiratory distress or lung bleeding: fever, breathlessness, coughing blood
- Severe allergic reactions
- Sickle cell crises in people with sickle cell disease
- Kidney inflammation (glomerulonephritis): less urine, dark urine, swelling
- Leukaemia or myelodysplasia reported in severe chronic neutropenia

## Contraindications

- Serious allergy to filgrastim or to proteins made in E. coli

## Key interactions

**Myelosuppressive chemotherapy given the same day**
Stimulated, dividing myeloid cells are more sensitive to cytotoxic drugs, so it is started after chemotherapy

## What is monitored

- Complete blood count with neutrophils
- Spleen-related pain and breathing
- Urine and kidney function if swelling or dark urine appear

## Administration and safety

- Subcutaneous injection (or intravenous infusion), started after chemotherapy, not during it
- Biosimilars and pegylated forms differ in schedule; check the exact product

## Nursing care

- Check the complete blood count as ordered
- Expect bone pain; report left upper abdominal or shoulder-tip pain at once
- Teach that infections can still occur: report fever or chills
- Teach subcutaneous injection and safe disposal if given at home

## Pregnancy and breastfeeding

Human data are limited; it is used in pregnancy when the benefit justifies it.

## Memory aid

«FILL the GRAnulocyte tank»: FIL-GRA-stim fills neutrophils, and the bones ache from the effort.

## Test yourself

Think of the answer, then tap the question to see it.

## Which receptor does filgrastim act on?

The G-CSF receptor on neutrophil progenitors.

## Which pain must be reported at once?

Left upper abdominal or left shoulder-tip pain (splenic rupture).

## In which inherited blood disease can it trigger crises?

Sickle cell disease.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/filgrastim/)

## Related drugs

- [Pegfilgrastim](https://durgical.com/en/pharmacology/pegfilgrastim/)
- [Sargramostim](https://durgical.com/en/pharmacology/sargramostim/)

## Related conditions

- [Febrile neutropenia](https://durgical.com/en/conditions/febrile-neutropenia/)
- [Neutropenia and drug-induced agranulocytosis](https://durgical.com/en/conditions/neutropenia-and-drug-induced-agranulocytosis/)

[← Back to the class: Myeloid colony-stimulating factors](https://durgical.com/en/pharmacology/classes/myeloid-colony-stimulating-factors/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Filgrastim Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a692033.html) (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 45 (McGraw Hill, 2023); Farmacología básica y clínica (Katzung), 16.ª ed., cap. 33 (McGraw Hill, 2025); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L03AA02) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/filgrastim/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/filgrastim/