Fasenra (benralizumab) is a prescription drug that’s used to treat conditions such as eosinophilic asthma. Fasenra is given as an injection under your skin.

Fasenra is used to treat:

This drug should not be used in certain cases. To learn more, see the “What is the Fasenra injection used for?” section below.

Fasenra basics

Fasenra’s active drug is benralizumab. (An active drug is an ingredient that makes a medication work.) It’s a kind of biologic drug. A biologic is made from parts of living organisms.

Fasenra belongs to a drug class called interleukin-5 monoclonal antibodies.

Fasenra is not available in a biosimilar form. (Biosimilars are like generic drugs. But unlike generics, which are made for non-biologic drugs, biosimilars are made for biologic drugs.)

Like most drugs, Fasenra may cause mild or serious side effects. The lists below describe some of the more common side effects that Fasenra may cause. These lists don’t include all possible Fasenra injection side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of Fasenra. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a short list of some of the mild side effects that Fasenra can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Fasenra’s prescribing information.

Mild side effects of Fasenra that have been reported include:

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Fasenra can occur, but they aren’t common. If you have serious side effects from Fasenra, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

The only serious side effect reported in studies of Fasenra was allergic reaction. To learn more about this side effect, see “Allergic reaction” just below.

Allergic reaction

For some people, Fasenra can cause an allergic reaction. But in studies of the drug, this side effect wasn’t common.

In general, symptoms of allergic reaction can be mild or serious.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should keep taking Fasenra.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Fasenra, they may have you switch to a different treatment.

Fasenra is used to treat:

  • severe eosinophilic asthma in adults and in children ages 6 years and older.
  • eosinophilic granulomatosis with polyangiitis (EGPA) in adults

Eosinophilic asthma results from a high level of white blood cells called eosinophils. These cells are part of your immune system. But with this condition, the cells mistakenly attack your body’s airways. This leads to swelling and damage, causing symptoms such as coughing, chest tightness, and nasal polyps.

With EGPA (also called Churg-Strauss syndrome), eosinophils cause your blood vessels to become inflamed and narrowed. This limits how much blood can flow through them. As a result, some organs may not receive enough blood, which can lead to organ damage. EGPA can cause symptoms such as shortness of breath, chest pain, and numbness in your hands or feet.

Fasenra works by attaching to eosinophils. It then sends signals to other cells in your body to destroy the eosinophils. This lowers the level of eosinophils in your body, helping to relieve symptoms.

Note: Fasenra should not be used to treat an asthma attack (sudden worsening of asthma symptoms). For this purpose, you should use a rescue inhaler, such as an albuterol inhaler (ProAir, Ventolin HFA), according to your doctor’s instructions.

Costs of prescription drugs can vary depending on many factors. These factors include what your insurance plan covers and which pharmacy you use.

If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. A program called Fasenra 360 may also help lower the cost of the drug.

Learn more about saving on your prescriptions and Fasenra and cost.

Your doctor will recommend the dosage of Fasenra that’s right for you. Below are commonly used dosages, but always take the dosage your doctor prescribes.

Forms and strength

Fasenra is a liquid solution given as an injection under the skin. It’s available in two forms:

  • single-dose, prefilled autoinjector pens
  • single-dose, prefilled syringes

Fasenra pens come in one strength: 30 milligrams (mg) per milliliter (mL) of solution (30 mg/mL).

Fasenra syringes come in two strengths: 10 mg/0.5 mL and 30 mg/mL.

Recommended dosages

Your doctor will recommend the dosage of Fasenra that’s right for you. Below are commonly used dosages, but the dosage you receive will be determined by your doctor.

Dosage for asthma

For treatment of asthma in adults and children ages 12 years and older, your doctor will likely prescribe a starting dose of one injection every 4 weeks for the first 12 weeks. Then your dosage will change to one dose every 8 weeks. You’ll receive 30 mg of Fasenra with each injection.

For children ages 6 to 11 years, Fasenra’s dosage is based on the child’s body weight in kilograms (kg). One kg equals about 2.2 pounds (lb). The dosage per kg is measured in milligrams per kilogram (mg/kg) and is calculated by your child’s doctor.

The following table shows the Fasenra’s usual dosages for children ages 6 to 11.

Body weight of children ages 6 to 11Dosage
less than 35 kg10 mg given as one injection every 4 weeks for the first 12 weeks, and then every 8 weeks after that
35 kg or more30 mg given as one injection every for the first 12 weeks, and then every 8 weeks after that

Dosage for eosinophilic granulomatosis with polyangiitis

For treatment of eosinophilic granulomatosis with polyangiitis, your doctor will likely prescribe one 30-mg injection every 4 weeks.

To learn more, see this Fasenra dosage article.

Questions about Fasenra’s dosage

Below are some common questions about Fasenra’s dosage.

  • What if I miss a dose of Fasenra? Call your doctor if you miss a dose of Fasenra. They’ll advise you on what to do and help you adjust your dosing schedule, if needed.
  • Will I need to use Fasenra long term? You’ll likely use Fasenra long term, if you and your doctor agree that the drug is working well and is safe for you.
  • How long does Fasenra take to work? Fasenra begins working immediately after you receive a dose. But it may take several weeks before you notice a reduction in your asthma symptoms.

Find answers to some commonly asked questions about Fasenra.

How does Fasenra work (what’s its mechanism of action)?

How a drug works is referred to as its “mechanism of action.”

Fasenra works by attaching to certain white blood cells called eosinophils. When Fasenra binds to eosinophils, it sends signals to other cells in your body to destroy eosinophils. This lowers the level of eosinophils in your body, relieving symptoms of your condition.

For more information about how Fasenra works to treat your condition, see the “What is the Fasenra injection used for?” section.)

Can Fasenra be used to treat nasal polyps?

Fasenra isn’t approved by the Food and Drug Administration (FDA) for treating nasal polyps. But one study found Fasenra effective for treating nasal polyps when used with corticosteroid nasal sprays.

The FDA is currently deciding whether to approve Fasenra for treating nasal polyps.

If you’re interested in learning more about treatments for nasal polyps, talk with your doctor.

What should I know about the Fasenra alternative drug Dupixent?

Fasenra and Dupixent (dupilumab) are both biologic medications prescribed to treat severe eosinophilic asthma in adults and some children. (Biologics are medications made from living cells rather than chemicals.)

Both are given as an injection under the skin.

But these drugs do have some differences as well. For example, Dupixent is also prescribed for treating certain conditions other than eosinophilic asthma.

To learn more about how Fasenra and Dupixent are alike and different, ask your doctor or pharmacist. They can also discuss with you the best treatment for your condition.

Does Fasenra cause any long-term side effects?

No, Fasenra isn’t known to cause long-term side effects. Long-term side effects weren’t reported in studies of the drug.

Long-term side effects are side effects that either:

  • start after you’ve taken a drug for a long time or after you end treatment, or
  • start during treatment and continue for a long time, possibly after treatment ends

Your doctor or pharmacist can answer any questions you may have about Fasenra and its long-term side effects. You can also see this Fasenra side effects article to learn more.

Is Fasenra used for COPD?

No, Fasenra isn’t used to treat chronic obstructive pulmonary disease (COPD).

One study didn’t find that the drug lowered the risk of COPD flare-ups. But another similar study is still gathering data about whether Fasenra might be an effective treatment for COPD.

If you’d like to learn about treatments for COPD, talk with your doctor or pharmacist.

Both Fasenra and Nucala (mepolizumab) are prescribed to treat severe eosinophilic asthma in adults and some children and eosinophilic granulomatosis with polyangiitis (EGPA) in adults. EGPA may also be called Churg-Strauss syndrome.

Fasenra and Nucala are kinds of biologic medications, which means they’re made from living cells rather than chemicals. And they’re both given as an injection under the skin.

To learn more about how Fasenra and Nucala are alike and different, check out the “Fasenra vs. Nucala” section in this Fasenra article. You can also ask your doctor whether one of these drugs may be right for you.

Fasenra and Xolair are both prescribed to treat asthma. But the kinds of asthma they’re used to treat differ.

Both Fasenra and Xolair (omalizumab) are biologic medications, which means they’re made from living cells rather than chemicals. They’re both given as an injection under the skin. While they can cause similar side effects, different side effects are possible with each drug.

To find out more about Fasenra and Xolair, see the “Fasenra vs. Xolair” section in this Fasenra article. Your doctor can also tell you more about how these drugs are alike and different.

A healthcare professional can give you doses of Fasenra at a doctor’s office, or you may give yourself doses at home. You and your doctor will decide which option is best for you.

Using Fasenra

Fasenra is given as an injection under the skin.

If you’ll give yourself Fasenra doses at home, your doctor will prescribe Fasenra pens to you. These are prefilled with Fasenra, and each pen contains a single dose of the drug. If you give yourself doses at home, be sure to follow your doctor’s instructions for the administration of Fasenra.

If a healthcare professional will give you Fasenra at a doctor’s office, they’ll use Fasenra prefilled syringes.

Accessible medication containers and labels

Certain pharmacies may provide medication labels that:

  • have large print
  • use braille
  • contain a code you can scan with a smartphone to change the text into audio

Your doctor or pharmacist may be able to recommend a pharmacy that offers these options if your current pharmacy doesn’t.

Using Fasenra with other drugs

Fasenra is used together with other asthma medications to treat severe eosinophilic asthma.

In studies of Fasenra, people took the drug along with a high dose inhaled corticosteroid (ICS) and a long-acting beta agonist (LABA). These kinds of drugs are typically found together in inhalers. Examples include:

People also took other asthma medications besides an ICS/LABA inhaler in these studies. Your doctor will tell you more about the other asthma medications you’ll take together with Fasenra.

Note: You should not use Fasenra to treat an asthma attack (sudden worsening of asthma symptoms). Instead, you should use a rescue inhaler, such as an albuterol inhaler, according to your doctor’s instructions. And if your asthma symptoms ever feel life threatening, call 911 or seek emergency medical help.

Questions about using Fasenra

Below are some common questions about taking Fasenra.

  • Should I take Fasenra with food? You may have Fasenra doses with or without food. Because the drug is given by injection, food won’t affect how well your body absorbs a dose. But some people who get nervous about injections find that eating helps calm their nerves.
  • Should I take Fasenra pens out of the refrigerator before giving myself a dose? Yes. Fasenra’s manufacturer recommends removing a Fasenra pen from the refrigerator about 30 minutes before giving a dose. This allows the medication to warm to room temperature. (A cold injection may be painful.)
Questions for your doctor

You may have questions about Fasenra and your treatment plan. It’s important to discuss all your concerns with your doctor.

Here are a few tips that might help guide your discussion:

  • Before your appointment, write down questions such as:
    • How will Fasenra affect my body, mood, or lifestyle?
  • Bring someone with you to your appointment if doing so will help you feel more comfortable.
  • If you don’t understand something related to your condition or treatment, ask your doctor to explain it to you.

Remember, your doctor and other healthcare professionals are available to help you. And they want you to get the best care possible. So don’t be afraid to ask questions or offer feedback on your treatment.

Certain factors may affect how well Fasenra works to treat asthma. These include your medical history and any medications you may take. Below are some of the important considerations to discuss with your doctor before you start receiving Fasenra.

Interactions

Taking a medication with certain vaccines, foods, and other things can affect how the medication works. These effects are called interactions.

There aren’t known interactions between Fasenra and other medications, foods, or herbal supplements.

But it’s still important to tell your doctor and pharmacist about other medications or herbal supplements you take. This can help avoid any potential drug interactions.

To learn more, see this Fasenra interactions article.

Warnings

Fasenra may not be right for you if you have certain medical conditions or other factors that affect your health. (Conditions or factors that could prevent your doctor from prescribing a medication are called contraindications.) Talk with your doctor about your health history before you take Fasenra. Factors to consider include those in the list below.

Fasenra and alcohol

There’s no known interaction between alcohol and Fasenra.

But alcohol may trigger asthma attacks for some people. If you have asthma, talk with your doctor about whether it’s safe for you to consume alcohol.

Pregnancy and breastfeeding

It’s not known whether it’s safe to take Fasenra while pregnant or breastfeeding.

If you’re pregnant or breastfeeding, or planning to become pregnant or breastfeed, talk with your doctor about the benefits and risks of Fasenra treatment.

Do not take more Fasenra than your doctor prescribes. Using more than this can lead to serious side effects.

What to do in case you take too much Fasenra

Call your doctor if you think you’ve taken 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.

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.

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