Fasenra (benralizumab) is a prescription drug that’s used to treat severe eosinophilic asthma in adults and some children. The drug comes as a liquid solution that’s given as an injection under the skin.

Fasenra is prescribed for adults and children ages 6 years and older to treat eosinophilic asthma.

The active ingredient in Fasenra is benralizumab. Fasenra belongs to a group of drugs called interleukin-5 (IL-5) antagonists.

This article describes the dosages of Fasenra, as well as its strengths and how to take it. To learn more about Fasenra, see this in-depth article.

This section describes the usual dosages of Fasenra. Keep reading to learn more.

What are Fasenra’s forms?

Fasenra is available as a liquid solution that’s given as an injection under your skin.

There are two forms of Fasenra: a single-dose prefilled syringe and a single-dose autoinjector pen.

What strengths does Fasenra come in?

The prefilled syringe comes in strengths of 10 milligrams (mg) per 0.5 milliliters (mL) of solution and 30 mg/mL.

The autoinjector pen comes in a strength of 30 mg/mL.

What are the usual dosages of Fasenra in adults?

The information below describes dosages that are commonly injected or recommended. But be sure to use the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs. In some cases, doctors may adjust your dosage from those shown below.

Dosage for asthma

For your first three injections of Fasenra, one dose of 30 mg is given every 4 weeks. (This is considered a loading dose, meaning that you receive the drug more often at the start of treatment.) After the first three injections, a dose of 30 mg is given every 8 weeks.

What’s the dosage of Fasenra for children?

Fasenra can be used in children ages 6 years and older.

The dosage for children ages 12 years and older is the same as the dosage that’s used in adults. For the first three injections of Fasenra, one dose of 30 mg is given every 4 weeks. After that, a dose of 30 mg is given every 8 weeks.

For children ages 6 through 11 years, their dosage is based on whether they weigh more or less than 35 kilograms (kg), which is about 77 pounds.

  • For children who weigh less than 35 kg: For the first three doses, they’ll receive an injection of 10 mg every 4 weeks. After that, they’ll receive one dose of 10 mg every 8 weeks.
  • For children who weigh 35 kg or more: For the first three doses, they’ll receive an injection of 30 mg every 4 weeks. After that, they’ll receive one dose of 30 mg every 8 weeks.

For more information about Fasenra’s dosage for children, talk with your child’s doctor or a pharmacist.

How to use Fasenra

Fasenra is given as an injection under the skin. If you give yourself injections, you can inject the drug into the front of your thigh or your abdomen. If a caregiver or your doctor gives you the injections, they could also inject the drug into your upper arm.

To learn more about how to inject Fasenra, you can watch this video or see these step-by-step instructions.

Is Fasenra used long term?

Yes, Fasenra is typically prescribed as a long-term treatment. If you and your doctor determine that it’s safe and effective for your condition, you’ll likely use it long term.

If you give yourself injections of Fasenra at home, do not inject more than your doctor prescribes. Doing so can lead to harmful effects.

What to do in case you use too much Fasenra

Call your doctor right away if you think you’ve injected too much Fasenra. You can also call 800-222-1222 to reach America’s Poison Centers, or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

Below are answers to some commonly asked questions about Fasenra’s dosage.

Will my dosage affect the cost of Fasenra?

It could. Fasenra is given more often at the start of your treatment. If you have out-of-pocket costs, such as a copayment or coinsurance, this may mean that you pay more while you’re receiving a dose every 4 weeks. (After the first three doses, you’ll receive a dose every 8 weeks).

Your cost may also depend on whether you self-inject the drug or not. Receiving injections from your doctor may add additional costs for those office visits.

To learn how much you’ll likely pay for Fasenra, talk with your doctor or your insurance provider (if you have coverage). You can also check whether you qualify for the Fasenra 360 Savings Program, which could lower your cost of the drug.

Are side effects from Fasenra more common when I first start treatment?

It’s possible. Fasenra doses are given more often at the start of treatment. (The first three doses are given 4 weeks apart, then you’ll receive a dose every 8 weeks.) Because of this, some people may experience more side effects when beginning their treatment. After the first three doses, some side effects may be reduced as you receive the drug less often and as your body gets used to the medication.

Common side effects of Fasenra include headache and sore throat. To learn more about the drug’s side effects, see this article.

If you’re concerned about side effects during your Fasenra treatment, talk with your doctor or pharmacist.

What should I do if I miss a dose of Fasenra?

If you use Fasenra at home and miss a dose, call your doctor. They can give you instructions on what to do next.

To help make sure you don’t miss a dose, try using a medication reminder. You could also download a reminder app on your phone.

If you miss an appointment to receive a dose of Fasenra, call your doctor’s office as soon as possible to reschedule. They’ll adjust your dosing schedule as needed.

Disclaimer: Healthline 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.