Reviewed on 5/10/2022

What Is Benralizumab and How Does It Work?

Benralizumab is a prescription medicine used for the maintenance treatment of severe asthma in people 12 years and older with an eosinophilic phenotype.

  • Benralizumab is available under the following different brand names: Fasenra

What Are Dosages of Benralizumab?

Adult and pediatric dosage

  • Solution for SC injection (single-dose prefilled syringe)
  • 30mg/mL (single-dose prefilled syringe or autoinjector pen)

Severe Asthma

Adult dosage

  • 30 mg SC every 4 weeks for the first 3 doses, then every 8 weeks thereafter

Pediatric dosage

  • Children below 12 years: Safety and efficacy not established
  • Children above 12 years: 30 mg SC every 4 weeks for the first 3 doses, then every 8 weeks thereafter

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Are Side Effects Associated with Using Benralizumab?

Common side effects of Benralizumab include:

Serious side effects of Benralizumab include:

  • new or worsening asthma symptoms, and 
  • signs of an allergic reaction: hives, rash, difficult breathing, feeling light-headed, swelling of the face, lips, tongue, or throat.

Rare side effects of Benralizumab include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Benralizumab?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

  • Benralizumab has no noted severe interactions with any other drugs.
  • Benralizumab has no noted serious interactions with any other drugs.
  • Benralizumab has no noted moderate interactions with any other drugs.
  • Benralizumab has no noted minor interactions with any other drugs. 

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Benralizumab?


  • Hypersensitivity to benralizumab or any of its excipients

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Benralizumab?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Benralizumab?”


  • Hypersensitivity reactions (eg, anaphylaxis, angioedema, urticaria, rash) were reported; these reactions generally occur within hours of administration, but in some instances have a delayed onset (ie, days); discontinue if hypersensitivity occurs
  • Do not discontinue systemic or inhaled corticosteroids abruptly upon initiating benralizumab; corticosteroid dose reductions, if appropriate, should be gradual and performed under the direct supervision of a physician; monitor for systemic withdrawal symptoms and/or unmasking of conditions previously suppressed by systemic corticosteroid therapy
  • Eosinophils may be involved in the immunological response to some helminth infections; unknown if benralizumab influences immunologic response against helminth infections; treat patients with preexisting helminth infections before initiating therapy; if parasitic infection occurs while receiving treatment and does not respond to antihelminth treatment, discontinue benralizumab until the infection resolves
  • Avoid use in acute asthma symptoms or acute exacerbations; do not use it to treat acute bronchospasm or status asthmaticus

Pregnancy and Lactation

  • No data are available regarding use in pregnant women; a pregnancy exposure registry monitors pregnancy outcomes in women exposed to the drugs during pregnancy; healthcare providers can enroll patients or encourage patients to enroll themselves by calling 1-877-311-8972 or visiting
  • Monoclonal antibodies are transported across the placenta during the third trimester of pregnancy; therefore, potential effects on a fetus are likely to be greater during the third trimester of pregnancy
  • In women with poorly or moderately controlled asthma, evidence demonstrates an increased risk of preeclampsia in the mother and prematurity, low birth weight, and small gestational age in the neonate; closely monitor pregnant women and adjust treatment as necessary
  • Lactation
    • No information is available regarding the presence of benralizumab in human or animal milk, and the effects of benralizumab on the breastfed infant and milk production are not known
    • Humanized monoclonal antibodies and immunoglobulin G are present in human milk in small amounts
    • The development and health benefits of breastfeeding should be considered along with the mother’s clinical need for the drug and any potential adverse effects on the breastfed child or from the underlying maternal condition
Medscape. Benralizumab.

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