Using Neupogen to Treat a Low Neutrophil Count During Chemotherapy

Uses and side effects during chemotherapy

Neupogen (filgrastim) is a medication given to some people receiving chemotherapy to prevent or treat a condition called chemotherapy-induced neutropenia. Neutrophils are a type of white blood cell (WBC) that help prevent infection.

Neupogen works by stimulating the bone marrow to increase the production of white blood cells. After chemotherapy administration, the medication is given as a subcutaneous injection (in the tissue under the skin).

This article will explain what Neupogen is, along with its known side effects and benefits.

A syringe and two vials of chemotherapy drugs
Khuong Hoang / Getty Images

Neupogen With Breast Cancer

Chemotherapy for breast cancer destroys rapidly dividing breast cancer cells. Unfortunately, chemotherapy also affects healthy cells such as white blood cells, red blood cells, and platelets. The reduction of these healthy cells is referred to as bone marrow suppression from chemotherapy. When the number of WBCs is low, cancer patients are at increased risk of infection.

It's common for breast cancer patients to be prescribed Neupogen to help the bone marrow produce circulating WBCs, increasing the body's ability to fight germs.

How Neupogen Works

The body produces a protein called granulocyte colony-stimulating factor, which stimulates the production of neutrophils through a process called hematopoiesis. However, chemotherapy often reduces the number of WBCs faster than the bone marrow can produce them. Therefore, Neupogen (which is artificially produced G-CSF) is used to help speed up the bone marrow's production of WBCs.

A laboratory test called a complete blood count (CBC) is used to evaluate the absolute neutrophil count (ANC). If the ANC is low, then Neupogen can be given to help increase it. Preventing infections while undergoing chemotherapy is essential to maintaining health and well-being during cancer treatment.

Although Neupogen injections will boost the production of your neutrophils, it's important to report signs of an infection, including a fever (100.4 F or greater), to your oncology team immediately.


Neupogen is given as a daily injection until the ANC rises. The number of injections required depends on several factors, including CBC results, type of cancer, the chemotherapy regimen, and medical condition.

Injections are administered into the fatty tissue of the arms or abdomen. Your oncology nurse will rotate the sites daily. Sometimes Neupogen can be administered at home. On rare occasions, Neupogen can be given intravenously (through a vein in your arm).

Neupogen Side Effects

As with most medications, Neupogen injections may cause side effects. Here are side effects associated with Neupogen:

  • Bone pain: Usually felt in the chest bone, hips, and leg bones, bone pain is due to the increased activity in the bone marrow.
  • Allergic reaction: You may need to receive your first injection in the clinic to ensure you don't have an allergy to Neupogen.
  • Thrombocytopenia (decreased platelet count): Watch for signs of bleeding or petechiae (small red dots on the skin) while receiving Neupogen.
  • Leukocytosis (elevated WBC count): Too many white blood cells can lead to other medical issues.
  • Splenic rupture: If the spleen becomes too enlarged, it can rupture, leading to blood loss.
  • Acute respiratory distress syndrome (ARDS): Notify your healthcare provider if you develop fever or breathing problems while on Neupogen.

Relieving Bone Pain

Although nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are useful in alleviating bone pain, some studies show that taking the over-the-counter antihistamine Claritin (loratadine) while being treated with Neupogen can also help. Ask your oncology nurse for more information on how to decrease bone pain while on Neupogen.

Risks and Contraindications

Although Neupogen is relatively safe, medical conditions exclude some people from receiving it. Tell your oncologist (cancer doctor) if you have any of the following conditions before starting Neupogen:

When To Call Your Healthcare Provider

Reactions may sometimes occur. Call your healthcare provider right away if you develop signs of an allergic reaction (hives, problems breathing, swelling of the face, lips, tongue, or throat, rash spreading over your body), abdominal pain, shoulder pain, chest pain, or severe fatigue.

Neutropenic fever occurs when you have a fever and a low ANC. This condition is considered a medical emergency and requires immediate treatment. Report a fever of 100.4 F, shaking chills, cough, shortness of breath, burning with urination, or any other signs of infection to your oncology team right away.

Before Your First Injection

Before your first injection of Neupogen, your healthcare provider will order a CBC to assess your healthy blood cells. After that, you will need repeated CBCs to determine how well the Neupogen is working. If you are administering Neupogen at home, your oncology nurse will schedule an education session about how to give yourself an injection.

Other Ways to Lower Infection Risk

Although Neupogen can lower the risk of infection, here are other ways to say healthy during cancer treatment:

  • Practice good handwashing and hand sanitizing.
  • Stay away from sick people.
  • Don't receive live vaccines.
  • Ask your oncology nurse about the Neutropenic diet.
  • Eat healthily and stay hydrated.
  • Report any signs of infection to your oncology team.


Chemotherapy destroys cancer cells and healthy white blood cells, like neutrophils. If your neutrophil count is low, you can develop an infection that requires hospitalization. Neupogen is an effective way to prevent and treat a low neutrophil count.

Although tolerated well, Neupogen can cause mild to moderate bone pain. Soaking in a warm bath, staying hydrated, and using NSAIDs and Claritan can potentially alleviate bone pain. Be sure to report any signs of infection to your oncology team immediately.

Frequently Asked Questions

  • How long does it take for Neupogen to work?

    An increase in the neutrophil count is seen one to two days after starting Neupogen. Most patients will have a return to their pretreatment neutrophil count seven days after starting Neupogen.

  • How much does a Neupogen injection cost?

    An injection of Neupogen and similar colony-stimulating factors can cost as much as $4,000 a shot. Your out-of-pocket costs may be lower depending on your insurance coverage.

  • How long does bone pain last after receiving Neupogen?

    Bone pain can last one to four days after receiving Neupogen. Nonsteroidal anti-inflammatory drugs (NSAIDs) may help relieve discomfort. Studies also show that loratadine, the ingredient in Claritin, can be effective in treating bone pain associated with Neupogen.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Rigby KM, DeLeo FR. Neutrophils in innate host defense against Staphylococcus aureus infectionsSemin Immunopathol. 2012;34(2):237–259. doi:10.1007/s00281-011-0295-3

  2. Lee K, Kim J, Lee M, et al. A randomized, multicenter, phase II/III study to determine the optimal dose and to evaluate the efficacy and safety of pegteograstim on chemotherapy-induced neutropenia compared to pegfilgrastim in breast cancer patients: KCSG PC10-09. Supportive Care in Cancer. 2016. 24:1709-1717. doi:10.1007/s00520-014-2555-y

  3. NEUPOGEN. Administration options.

  4. Federal Drug Administration. Neupogen drug label.

  5. American Board of Internal Medicine (ABIM) Foundation. Drugs to Prevent Infection During Chemotherapy.

  6. Kirshner JJ, McDonald MC, Kruter F, et al. NOLAN: a randomized, phase 2 study to estimate the effect of prophylactic naproxen or loratadine vs no prophylactic treatment on bone pain in patients with early-stage breast cancer receiving chemotherapy and pegfilgrastim. Support Care Cancer. 2018;26(4):1323-1334. doi:10.1007/s00520-017-3959-2

Additional Reading

By Serenity Mirabito RN, OCN
Serenity Mirabito, MSN, RN, OCN, advocates for well-being, even in the midst of illness. She believes in arming her readers with the most current and trustworthy information leading to fully informed decision making.

Originally written by Pam Stephan
Pam Stephan is a breast cancer survivor.
Learn about our editorial process