If you have an asthma, your doctor may prescribe a drug called Fasenra.

Fasenra is a prescription medication used to treat severe eosinophilic asthma in adults and some children.

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 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.)

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

  • Prefilled needles.
  • Prefilled autoinjector pens.

“Information about the drug’s side effects, uses, and dosage can be found in this section.”

Mild or serious side effects may occur with Fasenra. Some of the more common side effects of Fasenra are described in the lists below. There are no lists that include all possible side effects of the injection.

Side effects of a drug can depend on other factors.

  • Your age.
  • You have other health conditions.
  • You take other drugs.

The doctor or the pharmacy can tell you more about the side effects of Fasenra. They can suggest ways to 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.

There are some mild side effects of Fasenra that have been reported.

  • There is a high degree of fever.
  • There is a throbbing head.
  • Injection site reaction
  • sore throat.

The side effects of many drugs can be gone in a few days. If they become intolerable, talk to your doctor or pharmacist.

Serious side effects

Serious side effects from Fasenra are not common. If you have serious side effects, call your doctor. If you think you have a medical emergency, you should call the 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

Some people may have an allergic reaction to Fasenra. But in studies of the drug, this side effect wasn’t common.

A mild allergic reaction can include some symptoms.

A more severe allergic reaction is not uncommon. A severe allergic reaction can cause swelling under your skin, usually in your lips, hands, or feet. They can include swelling of your mouth, throat, and tongue, which can cause breathing problems.

If you have an allergic reaction to Fasenra, call your doctor. If you think you have a medical emergency, call the emergency number.

Fasenra is used to treat severe eosinophilic asthma in adults and in children ages 12 years and older.

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:

Symptoms get worse with higher levels of eosinophils.

The works by attaching to eosinophils. It sends signals to other cells to destroy the eosinophils. This lowers the eosinophils in your body, which will help to relieve symptoms.

Note: Fasenra should not be used to treat other conditions caused by a high level of eosinophils. And it 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.

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:

  • Prefilled needles.
  • Prefilled autoinjector pens.

The pens and needles come in one strength, 30 milligrams per liter of solution.

Recommended dosages

The first 12 weeks of the program are when the starting dose is given. Every 8 weeks, your dose will change to one dose.

You may need to go to a doctor’s office to have your injections. Or you may be able to give yourself injections at home. For details, see the “How is Fasenra used?” section below.

Questions about Fasenra’s dosage

Some questions about the dosage of Fasenra are listed below.

  • 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 improvement in your asthma symptoms.

Find out what the answers are to some questions.

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

Themechanism of action is what a drug works on.

Fasenra is used to treat severe eosinophilic asthma in adults and some children. (For more information, see the “What is the Fasenra injection used for?” section above.)

The white blood cells called eosinophils are attached to Fasenra. When you have Fasenra in your body, it sends signals to other cells to destroy eosinophils. This lowers the level of eosinophils in your body, which is a relief for symptoms of asthma.

Can Fasenra be used to treat There are nasal polyps.?

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

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

If you’re interested in learning more about treatments for There are 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.

Some of the drugs have differences. Dupixent is also used for treating other conditions.

Ask your doctor or pharmacist if you know how Fasenra and Dupixent are different. They can discuss 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.

Side effects that last for long are also called long-term side effects.

  • After you end treatment, start after taking a drug for a long time.
  • Continue for a long time after treatment ends.

Your doctor or pharmacist can answer questions about the drug.

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, see this article, or talk with your doctor or pharmacist.

Both Fasenra and Nucala (mepolizumab) are prescribed to treat severe eosinophilic asthma in adults and some children.

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 this side-by-side comparison. You can also ask your doctor if one of these drugs may be right for you.

Both Xolair and Fasenra are used to treat asthma. The kinds of asthma they 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 this article. Your doctor can also tell you more about how these drugs are alike and different.

“You can either get a dose at a doctor’s office or at home. You and your doctor will make a decision.”

“If you give yourself doses at home, you should follow your doctor’s instructions.”

Using Fasenra

Fasenra is given as an injection under the skin.

If you give yourself a home-delivered dose of Fasenra, your doctor will prescribe it to you. Each pen contains a single dose of the drug.

“If you go to a doctor’s office, they will use prefilled needles for Fasenra.”

Accessible medication containers and labels

If you use a pen that is hard to read on your prescription, you should tell your doctor or pharmacist. Some pharmacies may provide medication labels.

  • Have a large print.
  • Use the visual aids.
  • You can use a code on a phone to change the text into audio.

“If your current pharmacy doesn’t offer these options, your doctor or pharmacist may be able to recommend a new pharmacy.”

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 took other asthma medications besides the one they were using. You will be told more about the other asthma medications you take 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

Some questions about taking Fasenra are listed below.

  • Should I take Fasenra with food? You may receive 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 your treatment plan. Discuss your concerns with your doctor.

Here are a few tips that might help you.

  • Before your appointment, write down questions such as:
    • How will the effects of Fasenra affect me?
  • Bring someone with you to your appointment to make you feel more comfortable.
  • “If you don’t understand something, ask your doctor to explain it.”

“Your doctor and other healthcare professionals are available to help you. They want you to get the best care possible. Don’t be afraid to ask questions or give feedback on your treatment”

Some factors may affect how well Fasenra works. Your medical history and any medications you take are included. Before you start receiving Fasenra, you should have a discussion with your doctor.


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

There are no known interactions between Fasenra and other drugs.

It is still important to tell your doctor and pharmacist about your other medications. This can help avoid drug interactions.


If you have a medical condition that affects your health, it may not be right for you to use Fasenra. contraindications are conditions or factors that could prevent your doctor from giving you a medication. Before you take Fasenra, talk to your doctor about your health history. The factors to consider are listed below.

  • Parasitic infection. It’s not known whether treatment with Fasenra affects your body’s ability to fight a parasitic infection. If you have a parasitic infection, your doctor will likely treat this first before prescribing Fasenra.
  • Allergic reaction. If you’ve had an allergic reaction to Fasenra or any of its ingredients, your doctor will likely not prescribe the drug. Ask them what other medications are better options for you.

Fasenra and alcohol

There is no known interaction between alcohol and Fasenra.

Some people may have asthma attacks if they drink alcohol. If you have asthma, you should talk to your doctor about whether you should drink alcohol.

Pregnancy and breastfeeding

It is not known if it is safe to take Fasenra while pregnant or breastfeeding.

If you receive Fasenra while pregnant, consider joining the Fasenra pregnancy registry. Pregnancy registries gather data on the safety of using medications such as Fasenra during pregnancy. This helps doctors in making recommendations about the care of their patients. To learn more about the registry, visit the website or call 877-311-8972.

If you are pregnant or breastfeeding, you should talk to your doctor about the benefits and risks of Fasenra treatment.

There are many factors that affect the cost of prescription drugs. What your insurance plan covers is one of the factors.

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.

You can also check out this article to learn more about saving money on prescriptions.

Do not take more than your doctor prescribes. Side effects can be serious if you use more than this.

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 the American Association of Poison Control 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.

If you have severe eosinophilic asthma, your doctor may suggest you use Fasenra. Before you begin treatment, talk with your doctor and pharmacist about this. Asking questions can help you decide if the drug is a good treatment option for you. Here are a few examples to help get you started:

  • What should I know about my asthma treatment?
  • Will I take other asthma medications with Fasenra?
  • Is there a lower dose I can try if I have side effects from Fasenra?

This article will give you more information about treatments for your condition.

To receive news about treatments and advice on managing your condition, consider signing up for Healthline’s allergies and asthma newsletter.


I am giving myself a dose of the drug at home. I need to know how to store my pens.



These tips for storing your pens at home are available.

  • Keep the pen in its original carton until you need it. Keeping the drug out of the light is a benefit.
  • Do not expose the pens to heat.
  • The pens can be kept in their original cartons in the refrigerator at a temperature between 36F to 46F.
  • You can keep the pens at a room temperature of up to 77F (25C) for 14 days if you need to. You should discard unused medication at room temperature for a long time.
  • After giving yourself a dose, safely dispose of the Fasenra pen in a sharps container.

If you have questions about the storage and disposal of pens, ask your doctor or pharmacist.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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.