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Pronunciation: Phas-en-ra
Generic name: benralizumab
Dosage form: injection for subcutaneous use
Drug class: Interleukin inhibitors

Medically reviewed by Judith Stewart, BPharm. Last updated on Apr 12, 2024.

What is Fasenra?

Fasenra (benralizumab) is an injectable monoclonal antibody that affects the body's immune system by binding to the interleukin-5 receptor. It may be used as add-on therapy to treat severe eosinophilic asthma (SEA) in adults and children aged 6 years and older.

Fasenra is for people whose asthma is not well controlled with other medications.

Fasenra was FDA-approved on November 14, 2017.


Before you receive Fasenra, tell your doctor about all your medical conditions or allergies, all medicines you use, and if you are pregnant or breastfeeding.

Before taking this medicine

You should not be treated with Fasenra if you are allergic to benralizumab.

Tell your doctor if you have ever had:

Follow your doctor's instructions about receiving this medicine if you are pregnant. Not treating asthma during pregnancy could harm both mother and baby. Tell your doctor if you are pregnant or plan to become pregnant.

It may not be safe to breast-feed a baby while you are using this medicine. Ask your doctor about any risks.

Fasenra should not be given to a child younger than 6 years old.

How is Fasenra given?

Before you start treatment with Fasenra, your doctor may perform tests to measure your eosinophil levels.

Fasenra is injected under your skin (subcutaneously) one time every 4 weeks for the first 3 doses, and then every 8 weeks.

Fasenra comes in a single dose prefilled syringe and in a single dose autoinjector.

A healthcare provider will inject Fasenra using the single-dose prefilled syringe.

If your healthcare provider decides that you or a caregiver can give the injection of Fasenra, you or your caregiver should receive training on the right way to prepare and give the injection using the Fasenra Pen autoinjector.

Follow your doctor's dosing instructions very carefully.

If you've been using a steroid medication, do not stop using it unless your doctor tells you to.

Fasenra is not a rescue medicine for asthma attacks. Use only fast-acting inhalation medicine for an attack. Seek medical attention if your fast-acting medicine does not work.

You may need frequent medical tests to help your doctor determine how long to treat you with Fasenra.

Asthma is often treated with a combination of drugs. Use all medications as directed and read all medication guides. Do not change your dose or dosing schedule without your doctor's advice. Your dose needs may change due to surgery, illness, stress, or a recent asthma attack. Tell your doctor if any of your medicines seem to stop working.

Dosing information

Usual Adult Dose for Asthma:

30 mg subcutaneously once every 4 weeks for the first 3 doses, then once every 8 weeks thereafter

-This drug should be injected into the upper arm (for caregiver administration only), thigh, or abdomen.

Use: For add-on maintenance therapy of patients with severe asthma with an eosinophilic phenotype

Usual Pediatric Dose for Asthma:

12 years and older:

Inject under the skin (subcutaneously) of the upper arm (for caregiver administration only), thigh, or abdomen.

6 years to 11 years of age:

Inject under the skin (subcutaneously) of the upper arm (for caregiver administration only), thigh, or abdomen.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your Fasenra injection.

What happens if I overdose?

Since this medicine is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while receiving Fasenra?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Fasenra side effects

Get emergency medical help if you have signs of an allergic reaction to Fasenra: hives, rash; difficulty breathing, feeling light-headed; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

Common Fasenra side effects may include:

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 FDA at 1-800-FDA-1088.

What other drugs will affect Fasenra?

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

Popular FAQ

Monoclonal antibodies (mAbs) are man-made proteins that mimic the natural antibodies produced by our immune systems. Monoclonal antibodies can be formulated into medicines to treat various types of illnesses, such as cancer, rheumatoid arthritis or psoriasis. Continue reading

Fasenra (benralizumab) works by depleting eosinophils, which are a type of white blood cells and part of the immune system that helps fight infection and cancer. No major safety concerns, however, have been identified to date. Continue reading

Fasenra (benralizumab) significantly decreases eosinophils in the blood within 24 hours of a dose. After 4 weeks of treatment with Fasenra, asthma exacerbations start to reduce and lung function starts to improve. Continue reading

Fasenra (benralizumab) is used as an add-on, maintenance treatment for people with eosinophilic asthma who are 12 years of age or older.

Fasenra targets and removes cells that play a key role in asthma. It blocks interleukin-5 (IL-5) and enhances the action of natural killer (NK) cells. It also depletes the numbers of eosinophils and basophils. Continue reading

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Further information

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