Filgrastim
Also known as: Neupogen, Filgen, Gran, Granulen, Granulokine, Neulasta, Neutromax
Your veterinarian has prescribed **filgrastim** to help your pet's bone marrow produce more white blood cells (specifically neutrophils), which are critical for fighting off severe infections. * **Cost:** This medication is a human recombinant product and is very expensive. * **Important Risks:** Because this is a human protein, your pet's immune system may recognize it as foreign and create antibodies against it. If this happens, the immune system may destroy both the drug and your pet's own natural white blood cells, leading to a life-threatening drop in immunity. * **Short-term Use:** To minimize this risk, filgrastim is usually only given for a very short period (3 to 5 days) to get your pet through the most critical phase of their illness. * **Monitoring:** Frequent blood tests will be required to ensure the medication is working and to watch for any adverse immune reactions.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Adjunctive therapy of neutropenia (secondary to drug induced aplastic pancytopenia)
- Neutropenia
- Neutropenia
- Neutropenia secondary to drug toxicity, infectious diseases, FeLV associated cyclic neutropenia or idiopathic causes
- Neutropenia
- Adjunctive therapy of neutropenia
- Neutropenia
How it is given
Possible side effects
- Severe neutropenia (due to autoantibody formation against G-CSF)
- Myelofibrosis (theoretical/reported concern)
- Medullary histiocytosis (theoretical/reported concern)
- Injection site irritation
- Bone pain
- Splenomegaly
- Hypotension
Cautions & contraindications
- Hypersensitivity to filgrastim
- Patients that have previously developed antibodies to filgrastim with resultant neutropenia
- > **High Risk of Immunogenicity:** The development of neutralizing antibodies can cause severe, prolonged neutropenia. Use should generally be restricted to short pulse therapy (≤ 5 days). * **Pregnancy:** FDA Category C. High doses have shown adverse effects in pregnant laboratory animals. Use only when benefits clearly outweigh risks. * **Nursing:** Unknown if excreted in milk, but unlikely to pose significant risk to nursing offspring. * **Efficacy vs. Risk:** Use is controversial due to cost, antibody potential, and lack of definitive evidence showing reduced mortality compared to aggressive broad-spectrum antibiotic therapy alone.
Drug interactions
- Antineoplastics: Avoid using filgrastim within 24 hours of administering antineoplastic agents that target rapidly proliferating cells, as it may exacerbate toxicity to the newly stimulated myeloid cells.
- Corticosteroids: May potentiate the release of neutrophils during G-CSF therapy.
- Lithium: May potentiate the release of neutrophils during G-CSF therapy.
- Cytotoxic Chemotherapy: Concurrent administration may increase the incidence of adverse effects. The stimulatory effects of G-CSF on haemopoietic precursors render them more susceptible to the effects of chemotherapy.
Frequently asked questions
What is Filgrastim used for in pets?
Your veterinarian has prescribed **filgrastim** to help your pet's bone marrow produce more white blood cells (specifically neutrophils), which are critical for fighting off severe infections. * **Cost:** This medication is a human recombinant product and is very expensive. * **Important Risks:** Because this is a human protein, your pet's immune system may recognize it as foreign and create antibodies against it. If this happens, the immune system may destroy both the drug and your pet's own natural white blood cells, leading to a life-threatening drop in immunity. * **Short-term Use:** To minimize this risk, filgrastim is usually only given for a very short period (3 to 5 days) to get your pet through the most critical phase of their illness. * **Monitoring:** Frequent blood tests will be required to ensure the medication is working and to watch for any adverse immune reactions.
Is Filgrastim safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
Worried about your pet?
Peqaboo’s AI helps you track symptoms, understand lab reports, and know when to see a vet.
Get the Peqaboo app