Neulasta in Breast Cancer Chemotherapy and Side Effects

Neulasta is administered via an injection.
Neulasta is administered via an injection. BSIP/UIG/Getty Images

How is Neulasta used during breast cancer chemotherapy and what are some common side effects?

What is Neulasta (Pegfilgrastim)?

Neulasta (pegfilgrastim) is a drug given to patients who have chemotherapy-induced neutropenia (a low neutrophil count - one type of white blood cell). An injection of Neulasta stimulates white blood cell production with a synthetic version of a granulocyte colony-stimulating factor (G-CSF).

It is a clear liquid that is usually given as a shot in which the needle is inserted just under the skin.

Use For Breast Cancer

Chemotherapy for breast cancer affects all the rapidly dividing cells in your body, including bone marrow cells, which produce white blood cells, red blood cells, and platelets. This bone marrow suppression during chemotherapy can result in anemia (a low red blood cells count), neutropenia (a low neutrophil count) and thrombocytopenia (a low platelet count.)

A low neutrophil count (sometimes simply called a low white blood cell count) can be serious in that it can predispose people receiving chemotherapy to infections. The goal of using Neulasta is to help prevent these infections.

How Neulasta Works

Usually, your body produces a protein that stimulates the production of neutrophils. During chemotherapy, your body's own production of neutrophils is interrupted, Neulasta functions to stimulate production of neutrophils, and to mature and activate neutrophils already present.

How Neulasta is Given

You will get an injection of Neulasta about 24 hours after your chemotherapy infusion. It may not be given sooner because it may be less effective. Unlike Neupogen, which must be given repeatedly until your neutrophil counts rise, Neulasta is given just once per a 2- or 3-week chemotherapy cycle.

You can have this injection in your upper arm, abdomen, thigh, or buttocks.

Some oncologists have patients given themselves their own injection the day following chemotherapy, and an automatic "on body injection" is also available.

Some Common Side Effects

Not everyone has side effects from Neulasta, but here are the most commonly known:

  • Bone pain - Nearly a third of people given Neulasta injections mention some type of bone pain.
  • Fever.

If you do have these side effects, you can take Tylenol (acetaminophen) or Advil (ibuprofen) to help reduce pain and fever. Soaking in a hot bath can also help with bone pain from Neulasta.

Call Your Doctor if You Have These Symptoms

  • Unusual fatigue and lethargy.
  • Chest pain.
  • Heart palpitations.

Urgent Symptoms Include

  • Hives; problems breathing; swelling of face, lips, tongue or throat; rash spreading over your body (signs of an allergic reaction.)
  • Abdominal pain, especially pain in your left upper abdomen.
  • Shoulder pain.

Possible Risks of Using Neulasta

Neulasta is a very safe drug used for many types of neutropenia. There are usually no ill effects from this drug. Any side effects you experience will taper off and cease when you stop receiving Neulasta shots. Below is a list of potential adverse reactions, but these are very rare.

  • Serious allergic reactions.
  • Adult respiratory distress syndrome (ARDS).
  • Sickle cell crisis in people with sickle cell anemia.
  • Splenic rupture.
  • Potential for stimulating tumor growth - This is a theoretical possibility as Neulasta is a growth factor.

Who Should Avoid This Drug

Do not take this drug if:

  • You are pregnant or breastfeeding.
  • You are allergic to Neulasta.
  • You are allergic to products made using the bacteria E. coli.

Recommendations During Treatment

Before your first injection of Neulasta, your doctor will order regular CBC's (complete blood counts) to get the levels of your platelets and red and white blood cells, with special attention to the absolute number of neutrophils in your blood.

 As treatment progresses, you will have more blood tests to check the effectiveness of Neulasta.

If you are nursing or pregnant, discuss this with your doctor before taking Neulasta. There have not been enough studies done to determine the effect of this drug on breast milk or the human fetus.


FDA Advisory Committee. Neulasta. Updated 02/10/10.

Physician’s Desk Reference PDRhealth. Neulasta.