Pronunciation: nu-las-tah
Generic name: pegfilgrastim
Other brand names of pegfilgrastim include: Neulasta, Neulasta Onpro Kit
Dosage form: single-dose prefilled syringe for subcutaneous injection (6 mg/0.6 mL), single-dose prefilled syringe co-packaged with the on-body injector (6 mg/0.6 mL)
Drug class: Colony stimulating factors

Medically reviewed by Carmen Pope, Senior Medical Editor, B. Pharm. Last updated on Aug 17, 2026.

What is Neulasta?

Neulasta is used to stimulate neutrophil growth and reduce infection risk (manifested by febrile neutropenia) in adults and children with non-myeloid cancer receiving myelosuppressive anti-cancer medicines associated with a clinically significant rate of febrile neutropenia.

Neulasta is also used to increase survival in adults and children acutely exposed to high levels of radiation that damage the bone marrow, known as hematopoietic subsyndrome of Acute Radiation Syndrome (H-ARS).

• The effectiveness of Neulasta injection for H-ARS was only studied in animals because it could not be studied in people.
• The Neulasta Onpro on-body injector is not recommended for people being treated for H-ARS.

It is not used to help mobilize peripheral blood progenitor cells needed for hematopoietic stem cell transplantation.

Neulasta (pegfilgrastim) is a man-made form of granulocyte colony-stimulating factor (G-CSF), a protein that stimulates the growth of neutrophils, a type of white blood cell in your body. White blood cells help your body fight infections. Neulasta belongs to the drug class called leukocyte growth factors. It may also be called a colony-stimulating factor.

Neulasta injection gained FDA approval on January 31, 2002. Several biosimilars of Neulasta have been approved (see pegfilgrastim).

Side effects

The most common side effects of Neulasta are:

• bone pain
• pain in your arms or legs.

Serious side effects

Neulasta may cause the following serious side effects:

• Spleen rupture. Your spleen may become enlarged and can rupture. A ruptured spleen can cause death. Call your healthcare provider right away if you have pain in the left upper stomach area or your left shoulder.
• A serious lung problem called Acute Respiratory Distress Syndrome (ARDS). Call your healthcare provider or get emergency help right away if you have shortness of breath with or without a fever, trouble breathing, or a fast rate of breathing.
• Serious allergic reactions. Neulasta can cause serious allergic reactions, including anaphylaxis. These reactions can cause a rash over your whole body, shortness of breath, wheezing, dizziness, swelling around your mouth or eyes, fast heart rate, and sweating. If you have any of these symptoms, stop using Neulasta and call your healthcare provider or get emergency medical help right away. If you have an allergic reaction while the on-body injector is delivering your dose, grab the edge of the adhesive pad, peel the on-body injector off, and get emergency medical help right away.
• Skin reactions to the adhesive on the on-body injector. The on-body injector uses an acrylic adhesive. If you have reactions to acrylic adhesives, using this product may cause a significant reaction. Contact dermatitis and skin reactions such as rash, itching, and hives have been reported where the on-body injector is applied. Tell your healthcare provider about any skin reaction in the area where the device was placed, particularly redness or tenderness that persists or gets worse, which can be a sign of infection.
• Sickle cell crises. You may have a serious sickle cell crisis, which could lead to death, if you have a sickle cell disorder and receive Neulasta. Call your healthcare provider right away if you have symptoms of sickle cell crisis, such as pain or difficulty breathing.
• Kidney injury (glomerulonephritis). Kidney injury has occurred in people receiving Neulasta. Call your healthcare provider right away if you develop any of the following symptoms:
  • swelling of your face or ankles
  • blood in your urine or dark colored urine
  • you urinate less than usual
• Increased white blood cell count (leukocytosis). Your healthcare provider will check your blood during treatment with Neulasta.
• Decreased platelet count (thrombocytopenia). Your healthcare provider will check your blood during treatment with Neulasta. Tell your healthcare provider if you have unusual bleeding or bruising during treatment with Neulasta. This could be a sign of decreased platelet counts, which may reduce the ability of your blood to clot.
• Capillary Leak Syndrome. Neulasta can cause fluid to leak from blood vessels into your body's tissues. This condition is called "Capillary Leak Syndrome" (CLS). CLS can quickly cause you to have symptoms that may become life-threatening. Get emergency medical help right away if you develop any of the following symptoms:
  • swelling or puffiness and are urinating less than usual
  • trouble breathing
  • swelling of your stomach area (abdomen) and feeling of fullness
  • dizziness or feeling faint
  • a general feeling of tiredness.
• Myelodysplastic syndrome and acute myeloid leukemia. If you have breast cancer or lung cancer, when Neulasta is used with chemotherapy and radiation therapy, or with radiation therapy alone, you may have an increased risk of developing a precancerous blood condition called myelodysplastic syndrome (MDS) or a blood cancer called acute myeloid leukemia (AML). Symptoms of MDS and AML may include tiredness, fever, and easy bruising or bleeding. Call your healthcare provider if you develop these symptoms during treatment with Neulasta.
• Inflammation of the arteries (arteritis). Serious inflammation of the large and medium blood vessels that carry blood from your heart to the body, including the aorta (the largest artery), has been reported in people receiving Neulasta. It can happen as early as the first week of treatment. Symptoms may include fever, stomach (abdominal) pain, back pain, headache, neck pain, or generally feeling unwell. Call your healthcare provider right away if you develop these symptoms.
• A missed or partial dose from the on-body injector. Missed or partial doses have been reported when the on-body injector did not work as intended. If this happens, you may be at higher risk of neutropenia, febrile neutropenia, or infection. Call your healthcare provider immediately if you think the device may not have worked properly, because you may need a replacement dose.

Other side effects reported since Neulasta was approved include injection site reactions, application site reactions with the on-body injector (such as bleeding, pain, discomfort, bruising, and redness at the site), Sweet's syndrome (acute febrile neutrophilic dermatosis), cutaneous vasculitis, and bleeding into the lungs (alveolar hemorrhage).

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 the FDA at 1-800-FDA-1088 or to Amgen at 1-800-77-AMGEN (1-800-772-6436).

Before taking this medicine

You should not use Neulasta if you have had a serious allergic reaction to pegfilgrastim or filgrastim (Neupogen). These reactions have included anaphylaxis.

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

• sickle cell disorder;
• kidney disease;
• severe skin reactions to acrylic adhesives, if you are going to use the Neulasta Onpro on-body injector;
• a latex allergy. The gray needle cap on the prefilled syringe contains dry natural rubber, which is derived from latex. You should not give Neulasta using the prefilled syringe if you have a latex allergy. Tell your healthcare provider if you are allergic to latex before using the on-body injector as well, because a prefilled syringe is used to fill the device and latex may be transferred to your skin;
• acute myeloid leukemia;
• radiation treatment; or
• myelodysplasia syndrome (also called "preleukemia").

Tell your doctor if you are pregnant or breastfeeding. It is not known if Neulasta will harm your unborn baby or whether it passes into breast milk.

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Neulasta increases activity in the bone marrow, which can cause temporary changes on bone imaging scans. Tell the healthcare provider carrying out any bone scan that you are receiving Neulasta so the results can be interpreted correctly.

How should I use Neulasta?

Receiving myelosuppressive chemotherapy

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.
• Only receive a dose of Neulasta on the day your healthcare provider tells you to.

Neulasta is injected under the skin. A healthcare provider may teach you how to properly use the medication by yourself. Do not try to give the injection unless you or your caregiver has been trained by your healthcare provider.

• Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all the 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. Use a new prefilled syringe and call your healthcare provider.
• Do not use a prefilled syringe if it has expired, if the carton is open or damaged, if it has been dropped on a hard surface, if the gray needle cap is missing or not securely attached, or if the safety guard has already been activated.
• Neulasta can be injected into the thigh or the stomach area, avoiding a 2-inch area around the navel. The outer upper arm and the upper outer buttocks can only be used if someone else is giving the injection. Choose a different spot each time, and do not inject into skin that is tender, bruised, red, or hard, or into scars or stretch marks.
• After the injection, press a cotton ball or gauze pad over the site without rubbing, and apply a bandage if needed.
• The prefilled syringe does not have graduation marks and is designed to deliver the whole 6 mg/0.6 mL dose. It cannot be used to give a smaller dose.
• For a child who weighs less than 99 pounds (45 kg), the dose is prepared from a single-dose vial. Only a healthcare provider should prepare and give doses from the vial. The correct dose for a child this size cannot be accurately measured using the prefilled syringe.
• If it looks like medicine is still in the syringe barrel after you remove it from the skin, you may not have received a full dose. Call your healthcare provider right away.
• You may need medical tests to help your doctor determine how long to treat you with this medicine.

Store the prefilled syringe or vial in its original carton in the refrigerator at 36°F to 46°F (2°C to 8°C), protected from light. Do not shake.

• Take the syringe or vial out of the refrigerator and let it reach room temperature, 68°F to 77°F (20°C to 25°C), for at least 30 minutes before injecting your dose. Do not warm it in any other way.
• Do not use a syringe or vial that has been left at room temperature for longer than 48 hours.
• Do not freeze the prefilled syringe. 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 freeze vials.

Keep Neulasta and all medicines out of the reach of children. Do not use Neulasta for a condition it was not prescribed for, and do not give it to other people, even if they have the same symptoms as you.

Neulasta Onpro

The Neulasta Onpro on-body injector is a device placed on the skin by a healthcare provider that delivers your pegfilgrastim dose at a set time. The on-body injector is for adults only and has not been studied in children. Your healthcare provider fills the device from a prefilled syringe and applies it to your stomach area (abdomen) or the back of your arm, on skin that is free of swelling, redness, cuts, wounds, or abrasions. If it is placed on the back of your arm, a caregiver must be available to check on it.

• The device is programmed to start delivering your dose about 27 hours after it is applied. The dose is then delivered over about 45 minutes.
• Have a caregiver with you the first time you receive Neulasta with the on-body injector.
• Stay somewhere you or a caregiver can watch the device during the 45-minute delivery and for 1 hour afterwards.
• Keep the device and adhesive backing dry for at least 3 hours after it is applied, and for about 3 hours before delivery is due to start. Keeping it dry before delivery makes leaks easier to spot.
• Keep the device at least 4 inches away from electrical equipment such as cell phones, cordless phones, microwaves, and other common appliances. Being too close may stop it working correctly and lead to a missed or incomplete dose.
• Only expose the device to temperatures between 41°F and 104°F (5°C and 40°C).
• Before your next scheduled Neulasta dose, avoid the use of lotions, creams, or oils on your arms and stomach area (abdomen) to help keep the device on your skin.
• Do not use other materials to hold the on-body injector in place that could cover audio/visual indicators or compress the on-body injector against your skin, as this could dislodge the cannula and lead to a missed dose or incomplete dose of Neulasta.
• The prefilled syringe packed with the Onpro kit must only be used with the on-body injector. Using it for a manual injection will give you an overdose, and using a manual-use syringe with the device may give you less than your prescribed dose.
• 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. Do not freeze the kit.
• Each prefilled syringe or Onpro Injector is for one use only. Throw it away after one use.

Checking the status light while you wear the device:

• A flashing green light means the device is working. Do not remove it.
• A long beep followed by a solid green light, or the light going out, means delivery is finished and the device can be removed. The fill indicator should read empty.
• A flashing red light and beeping means there is a problem. Call your healthcare provider right away.

Call your healthcare provider right away, as you may need a replacement dose, if:

• the on-body injector comes off before or during dose delivery. Do not re-apply it.
• the on-body injector is leaking, or the adhesive becomes noticeably wet (saturated) with fluid or is dripping.
• the status light on the on-body injector is flashing red.
• the fill indicator does not read empty after delivery should have finished.

To take the device off, grab the edge of the adhesive pad and peel it off slowly rather than pulling on the body of the device. Any adhesive left on the skin can be washed off with soap and water.

Use a needle and syringe only once and then place them in an FDA-cleared sharps disposal container. The used on-body injector also has to go into a sharps container because it contains a needle, batteries, and electronics. If the needle is showing after you remove the device, call your healthcare provider right away. Follow state or local laws about how to dispose of the container, and keep it out of the reach of children and pets. More information on safe sharps disposal is available at fda.gov/safesharpsdisposal.

Acute Radiation Syndrome

Your healthcare provider will administer this medicine to you.

• Two doses will be administered subcutaneously (under the skin), one week apart.
• The Neulasta Onpro on-body injector is not recommended for this use.

Dosing information

Dosage of Neulasta for patients receiving myelosuppressive chemotherapy

• Adults of any weight and children weighing 45 kg (99 pounds) or more: 6 mg SC once per chemotherapy cycle.
• Children 31 to 44 kg: 4 mg (0.4 mL) SC
• Children 21 to 30 kg: 2.5 mg (0.25 mL) SC
• Children 10 to 20 kg: 1.5 mg (0.15 mL) SC
• Children less than 10 kg: 0.1 mg/kg (0.01 mL/kg) SC

Doses for children weighing less than 45 kg are prepared by a healthcare provider from the 4 mg/0.4 mL single-dose vial.

Do not administer between 14 days before and 24 hours after administration of cytotoxic chemotherapy.

Dosage of Neulasta for hematopoietic sub-syndrome of Acute Radiation Syndrome

Administer the first dose as soon as possible after suspected or confirmed exposure to radiation levels greater than 2 gray (Gy), and a second dose one week later.

Adults of any weight and children weighing 45 kg (99 pounds) or more

• Initial dose: 6 mg SC as soon as possible after exposure.
• 1 week later: 6 mg SC

Children weighing less than 45 kg

• 31 to 44 kg: 4 mg (0.4 mL) SC
• 21 to 30 kg: 2.5 mg (0.25 mL) SC
• 10 to 20 kg: 1.5 mg (0.15 mL) SC
• Less than 10 kg: 0.1 mg/kg (0.01 mL/kg) SC

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. If the on-body injector comes off, leaks, or does not deliver your full dose, do not re-apply it. Call your healthcare provider immediately, as a replacement dose may need to be given with a manual prefilled syringe.

Related/similar drugs

What happens if I overdose?

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

Overdose may cause a high white blood cell count (leukocytosis) and bone pain. Swelling (edema), shortness of breath, and fluid around the lungs (pleural effusion) were reported in one person who mistakenly used Neulasta on 8 days in a row.

What should I avoid while using Neulasta?

When using Neulasta Onpro, avoid:

• traveling, driving, or operating heavy machinery during hour 26 through hour 29 after the on-body injector is applied. This covers the 45-minute delivery period plus 1 hour afterwards.
• activities and places that stop you or a caregiver from checking the device during delivery.
• diagnostic imaging (such as CT scan, MRI, ultrasound, or X-ray), radiation treatment, and oxygen-rich environments such as hyperbaric chambers, as the device may be damaged and you could be injured.
• airport X-ray scans. Request a manual pat down instead, and take care during the pat down so the device is not knocked off.
• sleeping on the device, applying pressure to it, or bumping or knocking it off your body.
• getting body lotions, creams, oils, and skin cleansing products near the device, as these may loosen the adhesive.
• bath tubs, hot tubs, whirlpools, and saunas. You can shower while wearing the device, which is waterproof up to 8 feet for 1 hour, but check afterwards that it has not come loose.
• direct sunlight for more than 1 hour, as this may affect the medicine. Wear the device under clothing.
• peeling off or disturbing the adhesive before your full dose has been delivered.

What other drugs will affect Neulasta?

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

Ingredients

Active ingredient: pegfilgrastim

Inactive ingredients: acetate, polysorbate 20, sodium, and sorbitol in water for injection.

• Each 0.6 mL delivered dose from the prefilled syringe or the on-body injector contains pegfilgrastim 6 mg, acetate 0.35 mg, polysorbate 20 0.02 mg, sodium 0.02 mg, and sorbitol 30 mg in water for injection.
• Each 0.4 mL single-dose vial contains pegfilgrastim 4 mg, acetate 0.24 mg, polysorbate 20 0.02 mg, sodium 0.01 mg, and sorbitol 20 mg in water for injection.

Manufacturer

Neulasta (pegfilgrastim) is made by Amgen Inc., whose headquarters are in Thousand Oaks, California, USA. For product information, call 1-800-77-AMGEN (1-800-772-6436), or for Onpro on-body injector support call 1-844-MYNEULASTA (1-844-696-3852).

Neulasta Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There are 2 for Neulasta.

Neulasta, Neulasta Onpro biosimilar products

Biosimilar products can only be dispensed in place of the reference product if the healthcare provider specifically prescribes the biosimilar product by name.

Pharmacy laws for biosimilar prescribing may vary by state

Common questions about Neulasta

More FAQ

• Why do you take Claritin with Neulasta?
• What biosimilars have been approved in the United States?

View more FAQ

Further information

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

Medical Disclaimer