A Complete Guide to Neupogen: Uses, Dosage, Side Effects, and Precautionary Measures

Neupogen (filgrastim) is an injectable medicine used to treat or prevent neutropenia (low neutrophil levels) in certain patients, including people receiving cancer treatments like chemotherapy. Neutropenia is a condition in which your body has a low white blood cell count, particularly neutrophils, which fight bacterial and fungal infections. Neupogen helps reduce the risk of infections by stimulating neutrophil production in cancer patients. 

Neupogen (filgrastim) is manufactured by Amgen and was approved by the FDA in 1991. Currently, five biosimilars of this drug are available in the market, including Filkri, Nivestym, Nypozi, Releuko, and Zarxio. 

If you’ve received a Neupogen prescription from your oncologist, then this article is for you. Read on to learn more about Neupogen, how it works, its dosage, the side effects you can expect, and the precautions you should take. 

Indications (Uses)

The FDA has approved Neupogen (filgrastim) for several uses, including:

• To reduce the risk of serious infections due to a low white blood cell count in people with certain types of cancer (non-myeloid) who received chemotherapy.
• To help neutrophils recover faster after intensive chemotherapy in patients with acute myeloid leukemia (AML).
• To help the cancer patient’s neutrophil count recover more quickly after bone marrow or stem-cell transplantation.
• To move blood-forming stem cells from the bone marrow into the bloodstream before patients undergo stem-cell collection therapy.

• When a person has persistently or repeatedly low neutrophils, such as congenital neutropenia, cyclic neutropenia, and idiopathic neutropenia.
• To stimulate bone marrow recovery after severe radiation exposure, which has severely damaged blood-cell production.
• To increase survival in patients exposed to bone marrow-suppressing radiation. 

Neupogen: Mode of Action (MOA)

When cancer patients receive high-dose chemotherapy treatment, it also damages the bone marrow cells, which results in a significant reduction in the number of white blood cells, including neutrophils, in the blood circulation. 

Since the cancer patient’s bone marrow needs time to produce new infection-fighting white blood cells, these patients are at high risk of serious infection due to neutropenia (low neutrophil counts). 

Neupogen (filgrastim) speeds up neutrophil production. Neupogen is a granulocyte colony-stimulating factor (G-CSF), which the body also produces naturally. G-CSF normally acts on the bone marrow and boosts the production of neutrophils. 

Neupogen works like the body’s natural G-CSF, helping white blood cells mature faster into neutrophils and enter the bloodstream to fight bacteria and reduce infection risk. 

Neupogen: Drug Form

Neupogen is available as a liquid solution in both single-dose vials and single-dose prefilled syringes in the following strengths:

• Single-dose vials: 300 mcg/ml and 480 mcg/1.6 ml
• Prefilled syringe: 300 mcg/0.5 ml and 480 mcg/0.8 ml

Recommended Dosage 

Your doctor determines the dosage and duration of Neupogen based on your condition, treatment, and blood-cell counts. Recommended dosages vary depending on the condition being treated:

1. Dosage for Cancer Patients Receiving Chemotherapy

The recommended initial dosage for patients with AML or non-myeloid cancers receiving chemotherapy is 5 mcg/kg/day, which can be administered as a single daily subcutaneous injection, by short intravenous infusion (15 to 30 minutes), or by continuous intravenous infusion.

2. Dosage for Cancer Patients Undergoing Bone Marrow Transplantation

The recommended dosage of Neupogen following bone marrow transplantation (BMT) is 10 mcg/kg/day, which is given as an intravenous infusion no longer than 24 hours. The first dose should be administered at least 24 hours after chemotherapy and at least 24 hours after bone marrow infusion. 

3. Dosage for Patients Undergoing Bone Marrow Collection Therapy

For collecting a patient’s own stem cells from the blood, Neupogen is given as a subcutaneous injection under the skin at a dosage of 10 mcg/kg/day. The first dose is given at least 4 days before the first leukapheresis procedure and continues until the last leukapheresis.

4. Dosage for Patients with Severe Chronic Neutropenia

The initial dosage of Neupogen in patients with congenital neutropenia is 6 mcg/kg, given as a subcutaneous injection twice a day. In patients with idiopathic or cyclic neutropenia, the dosage is 5 mcg/kg as a single daily subcutaneous injection.

5. Dosage for Patients Exposed to Bone Marrow-Suppressing Radiation

For patients who are exposed to myelosuppressive doses of radiation, a dose of 10 mcg/kg is given as a single daily subcutaneous injection. The Neupogen should be administered as soon as possible after suspected or confirmed exposure to radiation doses greater than 2 gray (Gy).

How It Is Administered

Neupogen may be given as a subcutaneous injection under the skin. Your healthcare provider will show you how and where the injection should be given if you are administering Neupogen at home.

In some cases, Neupogen is also given as an intravenous injection, where a healthcare provider directly administers the drug solution into your vein. 

Side Effects

The most common side effects of Neupogen vary depending on the condition being treated and how the medication is used. For instance:

• Patients with non-myeloid cancers receiving chemotherapy may experience fever, pain, rash, cough, and shortness of breath.

• Patients with Acute myeloid leukemia receiving chemotherapy may have pain, nosebleeds, and rash.
• Non-myeloid cancer patients receiving chemotherapy followed by bone marrow transplant may have rash.
• People having their own blood cells collected may have bone pain, fever, and headache.
• Patients with severe chronic neutropenia may have pain, decreased red blood cells, nosebleeds, diarrhea, reduced sensation, and hair loss. 

Serious Side Effects

Patients taking Neupogen could also experience some adverse effects. Some of the reported serious effects of this medicine include:

• Spleen rupture
• Acute respiratory distress syndrome (a serious lung problem)
• Serious allergic reactions
• Sickle cell crises in people with sickle cell disorder
• Kidney injury
• Capillary leak syndrome (CLS)
• Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML)
• Decreased platelet count (thrombocytopenia)
• Increased white blood cell count (leukocytosis)
• Inflammation of your blood vessels (cutaneous vasculitis)
• Inflammation of arteries (arteritis)

Contact your healthcare provider right away if you develop signs or symptoms of a serious side effect while taking Neupogen. Your healthcare provider will determine whether treatment should be stopped or adjusted.

Precautionary Measures

Before you receive Neupogen, tell your healthcare provider about all of your medical conditions, including if you:

• Have a sickle cell disorder. 
• Have kidney problems. 
• Are receiving radiation therapy. 
• Are allergic to latex because the needle cap on the Neupogen prefilled syringe contains dry natural rubber (derived from latex). Do not use Neupogen with the prefilled syringe if you have latex allergies. 
• Are pregnant or plan to become pregnant. It is not known if Neupogen will harm your unborn baby. 
• Are breastfeeding or plan to breastfeed. It is not known if Neupogen passes into your breast milk. 
• Are taking any other medicines, such as prescription and over-the-counter medicines, vitamins, and herbal supplements

Cost

Neupogen can be expensive for people paying without insurance. The cash price can vary depending on the dose, pharmacy, location, and insurance coverage. For example, a 300 mcg/0.5 ml injection may cost around $334 per dose, while a 480 mcg/0.8 ml injection may cost around $527. Check with your pharmacy or insurance provider for current pricing and coverage information.

If the cost of Neupogen is a concern, your healthcare provider may consider an available filgrastim biosimilar when appropriate. Insurance coverage and out-of-pocket costs can vary by product. You can also contact us if you are interested in financial assistance or copay assistance for Neupogen.