Pronunciation: new-KAH-la
Generic name: mepolizumab
Dosage form: injection for subcutaneous use (prefilled pen, autoinjector, vial)
Drug class: Interleukin inhibitors

Medically reviewed by Carmen Pope, BPharm. Last updated on Apr 23, 2025.

What is Nucala?

Nucala is used to treat severe eosinophilic asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic granulomatosis with polyangiitis (EGPA), and hypereosinophilic syndrome (HES). It is self-administered by injection subcutaneously (under the skin) every 4 weeks, or a healthcare provider or caregiver can give it.

Nucala (mepolizumab) gained FDA approval on November 4, 2015. There is no generic or biosimilar.

FDA approvals and indications

Nucala is approved: 

• as an add-on maintenance treatment of severe asthma with an eosinophilic phenotype in adults and children aged 6 years and older. It is not a rescue medicine for acute bronchospasm or status asthmaticus 
• as an add-on maintenance treatment of chronic rhinosinusitis with nasal polyps (CRSwNP) in adults aged 18 years and older whose disease is not controlled with nasal corticosteroids. Nucala helps reduce symptoms (such as nasal congestion, nasal discharge, mucus in the throat, and loss of smell) and may help prevent surgery for nasal polyps
• to treat eosinophilic granulomatosis with polyangiitis (EGPA) in adults
• to treat hypereosinophilic syndrome [HES] in adults and children 12 years and older that has been present for 6 months or longer without an identifiable non-hematologic secondary cause.

Mechanism

Nucala works by reducing levels of eosinophils in the blood. Eosinophils are a type of white blood cell that are involved in inflammation. The mechanism of action of Nucala involves targeting and preventing the immune system protein interleukin-5 (IL-5) from interacting with its receptor on eosinophils, reducing eosinophil levels and inflammation.

Nucala belongs to the drug class interleukin inhibitors. It may also be called a monoclonal antibody and a biologic.

Side effects

The most common side effects of Nucala are:

• headache

• feeling tired

• mouth or throat pain

• back pain, joint pain

• pain, swelling, redness, burning, or itching where the medicine was injected.

Serious side effects and warnings

Nucala can cause the following serious side effects:

• Allergic (hypersensitivity) reactions, including anaphylaxis. Serious allergic reactions can happen hours or days after you get your Nucala injection. Get emergency medical help if you have signs of an allergic reaction such as hives, a rash, wheezing, chest tightness, difficulty breathing, feeling like you might pass out, or swelling of your face, lips, tongue, or throat.
• Herpes zoster infections. Herpes zoster infections, which can cause shingles, have happened in
  people who received Nucala. Call your doctor if you have symptoms of herpes zoster, such as skin sores or blisters, itching, tingling, burning pain, or a rash on your face or torso. 

If you also use an oral or inhaled steroid medication, do not stop using it suddenly. Talk to your healthcare provider about this.

Nucala injection is not approved for use in:

• HES in a child younger than 12
• Asthma in a child younger than 6
• EPGA or CRSwNP in patients younger than 18.

This is not a complete list of side effects, and others may occur. See the Nucala Prescribing Information for a full list or call your doctor for more information. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before using

Do not use Nucala if you are allergic to mepolizumab, Nucala, or any inactive ingredients in the injection.

Before receiving Nucla, tell your healthcare provider about all your medical conditions, including if you have ever:

• used an oral or inhaled steroid medicine
• had herpes zoster (also called shingles)
• had an infection caused by helminths (worm-like parasites).

Tell your doctor if you are pregnant or plan to become pregnant, or are breastfeeding or plan to breastfeed.

You may be given a zoster (shingles) vaccine before starting your Nucala injection.

Pregnancy

It is not known if Nucala may harm your unborn baby. Tell your doctor if you become pregnant while using this medicine. Your name may be added to a pregnancy registry to track the effects of Nucala on the baby.

Breastfeeding

You and your healthcare provider should decide if you will use Nucala and breastfeed. You should not do both without talking with your healthcare provider first.

How is Nucala administered?

Nucala is injected under the skin, usually once every 4 weeks.

• It can be given under the skin of your thigh or stomach (abdomen) or a caregiver can administer it under the skin of the back of your upper arm.
• A healthcare provider can teach you how to use the medication before you give it to yourself. Or your healthcare provider can give it to you every 4 weeks.
• The single-dose prefilled autoinjector is for use by people 12 years and older, and the single-dose prefilled syringe is for children 6 years and older, to be administered by a caregiver.
• Each Nucala prefilled syringe or autoinjector is for one use only. Throw it away after one use, even if there is still medicine left inside.

Read the Instructions for Use in the Nucala Package Insert that comes with Nucala or contact the MyNucala Patient Support Program for more details about self-administration.

Nucala is not a rescue medicine for asthma attacks. Use only a fast-acting bronchodilator such as albuterol for an asthma attack. Seek medical attention if your breathing problems get worse quickly, or if you think your asthma medications are not working as well.

Nucala dosing information

Severe eosinophilic asthma

Adults and children 12 years and older: 100 mg SC 1 time every 4 weeks.

Children aged 6 to 11 years: 40 mg SC 1 time every 4 weeks.

Chronic rhinosinusitis with nasal polyps (CRSwNP)

Adults: 100 mg SC 1 time every 4 weeks.

Eosinophilic granulomatosis with polyangiitis (EGPA)

Adults: 300 mg (as 3 separate 100mg injections) SC every 4 weeks.

Hypereosinophilic syndrome (HES)

Adults and children aged 12 and older: 300 mg (as 3 separate 100mg injections) SC every 4 weeks.

What happens if I miss a dose?

If you miss a dose, inject a dose as soon as possible. Then continue (resume) your injection on your regular dosing schedule.

If you do not notice that you have missed a dose until it is time for your next scheduled dose, then inject the next scheduled dose as planned. Do not use two doses at one time.

If you are not sure when to inject Nucala, call your healthcare provider.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What other drugs will affect Nucala?

Tell your doctor about all your current medicines and any you start or stop using, especially:

• oral or inhaled steroid medicines.

Other drugs may interact with Nucala, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your healthcare providers about all medicines you use now and any medicine you start or stop using. Formal drug interaction trials have not been performed with Nucala.

Storage

Store the Nucala prefilled syringe or Nucala autoinjector in the original carton in a refrigerator. Do not freeze or shake the medicine.

• After removing the medicine from the carton, you must use it within 8 hours.

You may store the prefilled syringe or autoinjector in the unopened carton at room temperature for up to 7 days.

• Throw away a syringe or autoinjector left out of the refrigerator for longer than 7 days.

Safely throw away medicine that is out of date or no longer needed.

Keep out of the reach of children.

Ingredients

Active Ingredient: mepolizumab.

Inactive Ingredients (vials): polysorbate 80, sodium phosphate dibasic heptahydrate, and sucrose.

Inactive Ingredients (prefilled autoinjectors and prefilled syringes): citric acid monohydrate, EDTA, disodium dihydrate, polysorbate 80, sodium phosphate dibasic heptahydrate, and sucrose.

Nucala for injection is available as:

• 100 mg of lyophilized powder in a single-dose vial for reconstitution
• 100 mg/mL single-dose prefilled autoinjector/syringe
• 40 mg/0.4 mL single-dose prefilled syringe. 

Who makes Nucala?

Nucala (mepolizumab) is a prescription medication manufactured by GlaxoSmithKline (GSK), a multinational pharmaceutical company. GSK's global headquarters are located in Brentford, London, United Kingdom. The company was formed through the merger of Glaxo Wellcome and SmithKline Beecham in 2000.

Nucala Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for Nucala.

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Further information

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