Neulasta (pegfilgrastim) is a brand-name drug that’s prescribed to treat radiation sickness and prevent certain complications of chemotherapy. Neulasta comes as an injectable solution. The dosage can vary depending on which condition the drug is used to treat.

Neulasta is approved by the Food and Drug Administration (FDA) to:

Neulasta is a biologic and belongs to a drug class called granulocyte colony-stimulating factors. Neulasta is available in biosimilar versions, such as Fulphila, Fylnetra, Nyvepria, Stimufend, Udenyca, and Ziextenzo.

Keep reading for specific information about the dosage of Neulasta, including its strength and how to use the medication. For a comprehensive look at Neulasta, see this article.

Note: This article describes typical dosages for Neulasta provided by the drug’s manufacturer. When taking Neulasta, always follow the dosage prescribed by your doctor. Your doctor will prescribe the Neulasta dosage that’s right for you.

Below is information about Neulasta’s forms, strength, and dosages.

Neulasta forms

Neulasta comes as a solution that’s given as a subcutaneous injection. It’s available as a prefilled syringe or in a Neulasta Onpro kit.

The Neulasta Onpro kit contains a prefilled syringe along with an on-body injector. Your doctor or caregiver will use the syringe to load the on-body injector before or during your chemotherapy appointment. Then, 27 hours later, the device will slowly release the Neulasta into your system. With Neulasta Onpro, you won’t have to return to your doctor’s office to receive your dose the day after chemotherapy.

Neulasta Onpro is not approved for use in children. In addition, it’s not approved to treat radiation sickness.

Neulasta strength

Neulasta comes in one strength of 6 milligrams (mg) per 0.6 milliliters (mL) of solution.

Typical dosages

The following information describes dosages that are commonly prescribed in adults. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Dosage for preventing infection during chemotherapy

Doctors may prescribe Neulasta to prevent febrile neutropenia and infection related to chemotherapy treatment.

For this purpose, the recommended dose of Neulasta is 6 mg. You’ll receive one dose of Neulasta per chemotherapy cycle. You’ll use one prefilled syringe or one Neulasta Onpro to complete your dose. Neulasta should not be given during the 14 days before your chemotherapy appointment or for 24 hours after.

Your doctor will explain the details of when and how you’ll receive Neulasta. In most cases, a healthcare professional will either give your dose using the prefilled syringe or apply the Onpro form (an on-body injector).

Dosage for radiation sickness

Neulasta is also approved to help treat acute radiation sickness. In this case, the recommended dose of Neulasta is two 6-mg doses. You’ll get your first dose as soon as possible after radiation exposure. Then, you’ll get your second dose 1 week later.

For radiation sickness, Neulasta is given by a healthcare professional using the syringe form of the drug. As a delayed-release system, Neulasta Onpro is not approved for this use.

Children’s dosage

As with adults, Neulasta is approved to prevent infection in children during chemotherapy. In addition, it’s also approved to treat radiation sickness.

The dosage is based on the child’s body weight in kilograms (kg). One kg equals about 2.2 pounds (lb).

The table below lists the typical dose for children receiving Neulasta:

less than 10 kg0.1 mg per kg of body weight
10–20 kg1.5 mg
21–30 kg2.5 mg
31–44 kg4 mg

If your child’s doctor prescribes Neulasta, they will likely prescribe the prefilled syringe form. If your child weighs 45 kg or more, they will receive the same dose as an adult. For more information, see the sections above. Talk with your child’s doctor if you have questions about their dosage.

Long-term treatment

How long you’ll use Neulasta depends on the condition it’s being prescribed to prevent or treat.

For preventing infection related to chemotherapy, Neulasta may be prescribed short term or long term. This depends on the length of your chemotherapy treatment.

For treating radiation sickness, Neulasta is a short-term treatment.

Talk with your doctor if you have questions about how long you can expect to take Neulasta.

The Neulasta dosage your doctor prescribes will depend on several factors. These include:

  • your age
  • body weight in children
  • the condition you’re using Neulasta to treat or prevent

Other medical conditions you have can also affect your Neulasta dosage.

Neulasta comes as a solution in a single-dose prefilled syringe. It’s also available in a Neulasta Onpro kit, which contains a prefilled syringe along with an on-body injector. If you have questions about which form of the drug is right for you, talk with your doctor.


Neulasta is given as a subcutaneous injection (an injection given under your skin). If you’re using the single-dose prefilled syringe, your doctor will give you your first dose. Then, they may show you or your caregiver how to do it. Make sure to inject Neulasta according to your prescribed instructions.

For more information about the typical dosing schedule for Neulasta, see the “Neulasta dosage” section above.

Neulasta Onpro

If you’re prescribed the Neulasta Onpro kit, you’ll receive a prefilled syringe along with an on-body injector. On the day of your chemotherapy appointment, a healthcare professional will load the injector with medication. Then, they’ll place the device on the skin of your abdomen or the back of your arm.

The on-body injector will release the drug about 27 hours after it’s applied to your skin. It will release the dose over about 45 minutes.

For step-by-step instructions on how to inject your dose of Neulasta or what to expect with Neulasta Onpro, see the prescribing information. If you have additional questions about Neulasta or Neulasta Onpro, talk with your doctor or pharmacist.


Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

If you miss giving yourself a dose of Neulasta with the prefilled syringe, contact your doctor. They can recommend when the best time would be to give your missed dose.

If you miss your appointment for a Neulasta injection at your doctor’s office, call the office to reschedule.

Once you have your Neulasta Onpro device applied to your skin, it’s important to monitor the device to be sure that it properly releases your dose of Neulasta. It’s possible that the device may leak or may not administer the medication as expected. If you notice this, be sure to call your doctor’s office right away. They can make sure that you get your dose of Neulasta.

If you miss your appointment for your Neulasta injection, call your doctor’s office as soon as possible to reschedule. If you need help remembering your appointments, try setting an alarm or downloading a reminder app on your phone.

It’s important that you do not use more Neulasta than your doctor prescribes. For some medications, taking more than the recommended amount may lead to harmful effects or overdose.

Symptoms of an overdose

Overdose symptoms of Neulasta can include:

If you receive more than the recommended amount of Neulasta

Call your doctor right away if you believe you’ve taken too much Neulasta. Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

Below are some frequently asked questions about Neulasta.

Is the dosage of Neulasta similar to the dosage of filgrastim?

It’s difficult to compare the dosages of Neulasta and Neupogen (filgrastim) for several reasons. These medications contain different active drugs and may be given in different ways.

For example, both Neulasta and filgrastim may be given as subcutaneous injections. However, filgrastim may also be given as an IV infusion. In contrast, Neulasta may be given as a delayed-release injection with the Neulasta Onpro kit.

In addition, drug dosages can vary depending on the condition you’re using it to treat. For instance, Neulasta is given once per chemotherapy cycle to help prevent infection caused by chemotherapy. For the same use, filgrastim may be given once per day for up to 2 weeks each chemotherapy cycle.

To learn more about how these drugs compare, talk with your doctor. They’ll prescribe the drug and dosage that’s right for you.

How long does it take for Neulasta to start working?

Neulasta starts to work right after you receive your first dose. However, you likely won’t feel the drug working in your body. Your doctor will monitor your condition through blood tests to check whether the drug is working.

It may take days or even weeks before the drug is fully effective to prevent infection or treat radiation sickness.

Talk with your doctor if you have questions about what to expect with Neulasta treatment.

The dosages in this article are typical dosages provided by the drug’s manufacturer. If your doctor recommends Neulasta for you, they will prescribe the dosage that’s right for you. Always follow the dosage that your doctor prescribes.

As with any drug, never change your dosage of Neulasta without your doctor’s recommendation. If you have questions about the dosage of Neulasta that’s best for you, talk with your doctor.

Besides learning about dosage, you may want other information about Neulasta. These additional articles might be helpful:

  • More about Neulasta: For information about other aspects of Neulasta, refer to this article.
  • Side effects: To learn about side effects of Neulasta, see this article. You can also look at the Neulasta prescribing information.
  • Details about cancer: For details about cancer and its treatments, see our cancer hub.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.