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Generic name: pegfilgrastimPEG-fil-GRAS-tim ]
Brand names: Neulasta, Neulasta Onpro Kit
Drug class: Colony stimulating factors

Medically reviewed by Philip Thornton, DipPharm. Last updated on Jan 26, 2023.

What is Neulasta?

Neulasta is a man-made form of a protein that stimulates the growth of white blood cells in your body. White blood cells help your body fight against infection.

Neulasta is a prescription medicine used to prevent neutropenia (a lack of certain white blood cells) that is caused by receiving chemotherapy.

Neulasta helps reduce the chance of infections.


Before using Neulasta, tell your doctor if you have sickle cell disorder, acute myeloid leukemia, myelodysplasia (also called "preleukemia"), or if you are allergic to latex.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Do not self-inject Neulasta if you do not fully understand how to give the injection and properly dispose of used needles and syringes.

Neulasta is usually given once per chemotherapy cycle. It should not be given within 14 days before or 24 hours after you receive chemotherapy.

Before taking this medicine

You should not use Neulasta if you are allergic to pegfilgrastim or filgrastim (Neupogen).

To make sure this medicine is safe for you, tell your doctor if you have ever had:

Tell your doctor if you are pregnant or breastfeeding.

How should I use Neulasta?

Use Neulasta exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. This medicine should not be given within 14 days before or 24 hours after you receive chemotherapy.

Neulasta is injected under the skin. A healthcare provider may teach you how to properly use the medication by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all instructions.

Your blood may need to be tested often.

Prepare your injection only when you are ready to give it. Do not use if the medicine looks cloudy, has changed colors, or has particles in it. Call your pharmacist for new medicine.

Carefully follow your doctor's instructions when giving Neulasta to a child who weighs less than 99 pounds (45 kilograms). The correct dose for a child this size cannot be accurately measured using the prefilled syringe.

You may need medical tests to help your doctor determine how long to treat you with this medicine.

Store the prefilled syringe in its original package in the refrigerator, protected from light. Do not shake or freeze.

Take the syringe out of the refrigerator and let it reach room temperature for 15 to 30 minutes before injecting your dose. If a syringe has become frozen, thaw it in a refrigerator. Do not use any syringe that has been frozen more than one time.

Do not use a syringe that has been left at room temperature for longer than 48 hours.

The Neulasta Onpro Injector is a special device placed on the skin that delivers your pegfilgrastim dose at a specific time. You will need to wear the device for 27 hours before the dose begins. The timed dose will then be released from the device slowly over a 45-miute period.

Keep Neulasta Onpro refrigerated until you are ready to wear it. Do not use an Onpro device that has been left out of a refrigerator for longer than 12 hours.

While wearing Neulasta Onpro, you or a caregiver will need to check the device to make sure it is working properly.

Each prefilled syringe or Onpro Injector is for one use only. Throw it away after one use, even if there is still medicine left inside.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

What happens if I miss a dose?

Call your doctor for instructions if you miss an injection, or if you have a problem with the Onpro device.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms include bone pain, pain when you breathe, feeling short of breath while lying down, wheezing, gasping for breath, cough with foamy mucus, cold, clammy skin, anxiety, rapid heartbeats.

What should I avoid while using Neulasta?

When using Neulasta Onpro: Avoid traveling, driving, or operating machinery while wearing the device.

Neulasta side effects

Get emergency medical help if you have signs of an allergic reaction to Neulasta: hives, skin rash, sweating, warmth or tingly feeling; dizziness, fast heartbeats; wheezing, difficulty breathing; swelling of your face, lips, tongue, or throat.

Capillary leak syndrome is a rare but serious side effect of pegfilgrastim. Call your doctor right away if you have signs of this condition, which may include: decreased urination, tiredness, dizziness or light-headed feeling, trouble breathing, and sudden swelling, puffiness, or feeling of fullness.

Call your doctor at once if you have:

Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.

Common Neulasta side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Neulasta?

Other drugs may interact with pegfilgrastim, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Popular FAQ

A biosimilar is a biological product that is similar to a reference biologic (usually the original product) and for which there are no clinically meaningful differences in terms of safety, purity, and potency. As an example, the biosimilar Amjevita (adalimumab-atto) was approved as the first biosimilar to Humira (adalimumab). Continue reading

Your doctor may prescribe a medicine known as a colony stimulating factor to boost your white blood cell count if you are having chemotherapy ("chemo"). Chemo drugs work by killing rapidly growing cancer cells, but blood levels of white blood cells (known as neutrophils) may also decrease. Neutrophils help to fight infection in your body. Lower levels of these white blood cells can increase your risk for infection, especially during chemotherapy. Continue reading

Fulphila (pegfilgrastim-jmbd), is a biosimilar to Neulasta (pegfilgrastim). A biosimilar is a biological product that is highly similar to a biologic already approved by the FDA (known as the reference product) and has no clinically meaningful differences in terms of safety, purity and potency from the reference product. Biosimilars can provide cost effective treatment options to already approved biologics. Continue reading

Udenyca (pegfilgrastim-cbqv) and Neulasta (pegfilgrastim) are both biological drugs containing pegfligrastim.

The US Food and Drug Administration (FDA) has approved Udencya as a biosimilar of Neulasta, which means it is "highly similar to, and has no clinically meaningful differences from" Neulasta - it is just as safe and effective and used in the same way. The two drugs, however, are not interchangeable. Continue reading

The “cbqv” suffix is found in the biosimilar name for Udenyca (pegfilgrastim-cbqv), a biologic drug used to prevent neutropenia (a lack of certain white blood cells) caused by receiving chemotherapy. The suffix is used to distinguish its name from the original reference product, in this case Neulasta (pegfilgrastim), which has no suffix. The suffix on biosimilars helps healthcare providers and patients realize the medicine is an approved biosimilar, but the suffix has no specific meaning itself. Continue reading

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Neulasta only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.