What are the side effects of Filgastrin (granulocyte-colony stimulating factor, G-CSF)?

Filgastrim (G-CSF) Side Effects

Filgastrim (G-CSF) commonly causes mild to moderate bone pain as its most consistent side effect, but can also cause serious adverse reactions including splenic rupture, acute respiratory distress syndrome, and allergic reactions. 1

Common Side Effects

The most frequently reported side effects of filgastrim include:

• Musculoskeletal effects:

  • Bone pain (occurs in up to 83% of patients) 2, 3
  • Arthralgia (joint pain)
  • Muscle spasms
  • Musculoskeletal pain
  • Pain in extremities

• General symptoms:

  • Headache (39%) 3
  • Fatigue (14%) 3
  • Fever/pyrexia
  • Body aches (23%) 3
  • Feeling hot/night sweats

• Laboratory abnormalities:

  • Increased alkaline phosphatase
  • Increased lactate dehydrogenase
  • Increased alanine aminotransferase
  • Decreased potassium, glucose, and blood urea nitrogen 3

Serious Adverse Reactions

Several serious but rare adverse reactions have been reported with filgastrim use 1:

1. Splenic rupture - potentially fatal, more common in stem cell transplantation settings
2. Acute respiratory distress syndrome (ARDS)
3. Serious allergic reactions - affecting skin, respiratory, or cardiovascular systems
4. Sickle cell crisis - can be fatal in patients with sickle cell disease (not reported with sickle cell trait)
5. Glomerulonephritis
6. Alveolar hemorrhage and hemoptysis
7. Capillary leak syndrome
8. Myelodysplastic syndrome (MDS)/Acute myeloid leukemia (AML) - increased risk reported in patients receiving chemotherapy with G-CSF support
9. Thrombocytopenia
10. Leukocytosis
11. Cutaneous vasculitis
12. Aortitis

Risk Factors and Special Considerations

• Dose-related effects: Higher doses of G-CSF are associated with increased frequency and severity of bone pain and other side effects 3

• Patient population differences:

  • Healthy donors experience higher rates of bone pain (52-84%) compared to cancer patients (20-38%) 4
  • Patients with congenital neutropenia generally require higher doses and may be at greater risk for developing MDS/AML 2

• Bleomycin-containing regimens: Increased risk of bleomycin pulmonary toxicity has been reported with G-CSF use in patients with Hodgkin lymphoma receiving ABVD regimens 2

Management of Side Effects

1. Bone pain management:

   • First-line: Nonnarcotic analgesics (acetaminophen, NSAIDs) 2, 4
   • Second-line: Antihistamines, opioids, or dose reduction 4
   • Naproxen has shown efficacy in clinical trials for pegfilgrastim-induced bone pain 4

2. Laboratory monitoring:

   • Monitor complete blood counts
   • Monitor liver function tests (transaminases, alkaline phosphatase)
   • Monitor electrolytes, particularly potassium

3. Patient education:

   • Inform patients about expected side effects
   • Advise on appropriate analgesic use
   • Instruct patients to report severe or unusual symptoms

Duration of Side Effects

Most side effects are transient and resolve within 7 days after discontinuation of filgastrim 5. The bone pain typically diminishes within the first few weeks of treatment in patients receiving chronic therapy 2.

Clinical Pearls

• The benefits of filgastrim (reduced infection risk, improved chemotherapy dose delivery, reduced mortality) generally outweigh the risks in appropriate clinical scenarios 2
• Bone pain is dose-dependent and can be effectively managed with prophylactic or as-needed analgesics
• Serious adverse events are rare but require prompt recognition and management
• Long-term safety data on the risk of MDS/AML development with G-CSF use are still being collected, but current evidence suggests the overall mortality benefit outweighs this potential risk 2