Nucala (mepolizumab) is a prescription drug used to treat a severe type of asthma and certain other inflammatory conditions. Nucala comes as an injection that you give under your skin.

If you have asthma, nasal polyps, or certain other inflammatory conditions, your doctor may suggest treatment with Nucala (mepolizumab). It’s a prescription drug that’s used to treat:

Note: If you’re prescribed Nucala for asthma, you should not use the drug for an asthma attack. If you have an asthma attack, use your rescue inhaler as directed by your doctor. (To learn more, see “Receiving other drugs with Nucala” in the “How is Nucala administered?” section.)

Nucala basics

Nucala contains the active ingredient mepolizumab. (An active ingredient is what makes a drug work.) Nucala is available in three forms, all of which are given as an injection under the skin:

  • liquid solution inside a prefilled syringe
  • liquid solution inside a prefilled auto-injector
  • powder inside a vial, which is mixed into a liquid

Nucala is a biologic medication. Biologics are made using parts of living organisms. Nucala is not available in a biosimilar form.

Biosimilars are like generic drugs, but they’re not exact substitutes of brand-name drugs, like generic drugs. A generic is an exact copy of the active ingredient in a brand-name medication. Biosimilars are a close alternative to the biologic (reference) drug. They’re considered to be as safe and effective as their reference drug. Like generics, biosimilars tend to cost less than brand-name medications.

Keep reading to learn more about Nucala, including the drug’s side effects, price, and dosage.

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All the conditions Nucala treats are caused by a high level of eosinophils, a kind of white blood cell that can cause inflammation (swelling and damage). Although the way Nucala works isn’t fully understood, the drug blocks proteins that increase inflammation. This reduces inflammation, which is thought to help treat symptoms of these conditions.

Nucala for eosinophilic asthma

Nucala is prescribed for eosinophilic asthma in adults and children ages 6 years and older. Eosinophilic asthma is a type of severe asthma characterized by a high level of eosinophils, a kind of white blood cell. Your body naturally makes eosinophils, and they usually help fight infection.

However, in people with eosinophilic asthma, eosinophils cause inflammation in the airways. Usually, a higher eosinophil level means you have more severe symptoms.

Symptoms of eosinophilic asthma include:

Nucala is used with other asthma medications to treat eosinophilic asthma and help prevent asthma attacks.

Note: If you’re prescribed Nucala for asthma, you should not use the drug for an asthma attack. Instead, use your rescue inhaler for an asthma attack, as directed by your doctor. (To learn more, see “Receiving other drugs with Nucala” in the “How is Nucala administered?” section.)

Nucala for chronic rhinosinusitis with nasal polyps

Nucala is prescribed for chronic rhinosinusitis with nasal polyps in adults. Chronic rhinosinusitis causes chronic (long-term) irritation and inflammation in your sinuses and nose. Nasal polyps are benign (noncancerous) growths in your nose.

Symptoms of chronic rhinosinusitis with nasal polyps include:

  • congestion in your nose and sinuses
  • reduced ability to smell, or loss of smell
  • nasal discharge
  • pain or pressure in your face

Nucala is usually prescribed with other treatments for this condition.

Nucala for eosinophilic granulomatosis with polyangiitis

Nucala is prescribed for eosinophilic granulomatosis with polyangiitis (EGPA), previously called Churg-Strauss syndrome, in adults. With EGPA, your blood vessels become inflamed. This means they become narrowed, which limits how much blood can flow through them. As a result, certain organs may not receive enough blood.

Symptoms of EGPA depend on how the condition affects your body and which areas it affects. Examples of symptoms include:

Nucala for hypereosinophilic syndrome

Nucala is prescribed for hypereosinophilic syndrome (HES) in adults and children ages 12 years and older. HES refers to a group of conditions characterized by a high level of eosinophils, a type of white blood cell. Your body naturally makes eosinophils, and they usually help fight infection. But with HES, your eosinophil level is very high, and eosinophils spread into tissues throughout your body.

The most commonly affected organs are the skin, heart, lungs, and nervous system, but it can affect any organ. This means symptoms can vary depending on which part of the body is affected. Examples of symptoms include:

Nucala is used to treat HES that doesn’t have a known blood-related cause. Examples of blood-related causes may include chronic eosinophilic leukemia, other blood cancers, or parasitic infections.

If you’re prescribed Nucala, you may wonder how it works to treat your condition. (This is also called a drug’s mechanism of action.)

Nucala is prescribed to treat four conditions. All these conditions are caused by a high level of eosinophils, a kind of white blood cell that causes inflammation (swelling and damage).

Although the way Nucala works isn’t fully understood, the drug blocks a certain protein that increases inflammation. This reduces inflammation, which is thought to help treat symptoms of these conditions.

If you’re interested in learning more about how Nucala works, talk with your doctor or pharmacist.

Your doctor will recommend the dosage of Nucala that’s right for you. The following table includes commonly used dosages, measured in milligrams per milliliter (mg/mL) of solution. Always use the dosage your doctor prescribes.

Forms and strengths

Nucala comes in three forms, all of which are given as an injection under the skin of the thigh, upper arm, or abdomen:

FormStrengthHow it’s given
liquid solution inside a prefilled syringe• 40 mg/0.4 mL*
• 100 mg/mL		Given by a healthcare professional at a doctor’s office or clinic. In some cases, your doctor can show you or a caregiver how to administer the injections at home.
liquid solution inside a prefilled auto-injector• 100 mg/mLGiven by a healthcare professional at a doctor’s office or clinic. In some cases, your doctor can show you or a caregiver how to administer the injections at home
powder inside a vial• 100 mgA healthcare professional will mix the powder with water and give it as an injection at a doctor’s office or a clinic.

* Note the 40 mg/0.4 mL dose is only for use in children ages 6 to 11 years.

Recommended dosage

The recommended dosage of Nucala is 1 injection every 4 weeks. This is the usual dosage regardless of the condition you’re using Nucala to treat. However, your doctor will determine what your specific dosage should be based on your age and condition.

Questions about Nucala’s dosing

Here are some common questions about Nucala’s dosing.

  • What if I miss a dose of Nucala? If you miss a Nucala dose, inject it as soon as you remember. Then, inject your next dose as scheduled. Do not inject more than one dose of Nucala to make up for a missed dose. This could raise your risk of side effects. If you miss an appointment to receive a Nucala injection, call your doctor’s office as soon as possible to reschedule.
  • Will I need to use Nucala long term? If you and your doctor agree that Nucala is safe and working well for you, you’ll likely use it long term.
  • How long does Nucala take to work? Nucala begins working shortly after your first dose. But it’s likely to take several weeks or even months before you notice your symptoms begin to ease.

Your doctor will explain how to inject Nucala (if you use it at home) or how it’ll be administered to you. If you self-inject Nucala, be sure to follow your doctor’s instructions.

Using Nucala

Nucala comes in three forms, all of which are given as an injection under the skin:

  • liquid solution inside a prefilled syringe
  • liquid solution inside a prefilled auto-injector
  • powder inside a vial, which is mixed into a liquid

The drug is injected under the skin of your thigh, upper arm, or abdomen.

You can receive any of these forms as injections at your doctor’s office or another healthcare facility. In some cases, your doctor may show you or a caregiver how to give Nucala injections at home using the prefilled syringes or auto-injector. Injections using the powder form are only given by healthcare professionals.

Accessible medication containers and labels

If it’s hard for you to read the label on your prescription, tell your doctor or pharmacist. 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 Nucala with other drugs

If you’re prescribed Nucala for asthma, you’ll also be prescribed a rescue inhaler to treat asthma attacks. You should not use Nucala to treat an asthma attack.

Examples of rescue inhalers include albuterol (ProAir HFA, others) and certain combination inhalers, such as budesonide/formoterol (Symbicort).

Talk with your doctor if you have questions about using your rescue inhaler during your Nucala treatment.

Whether or not you have health insurance, cost may be a factor when considering Nucala. What you’ll pay for Nucala may also depend on factors such as your treatment plan and the pharmacy you use.

If you have questions about how to pay for your prescription or the cost per dose, talk with your doctor or pharmacist. A program called Gateway to Nucala may also be available to you. You may be eligible for the drug’s Copay Program or Patient Assistance Program.

Like most drugs, Nucala may cause mild or serious side effects. The following lists describe some of the most common side effects of Nucala. These lists don’t include all possible 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 Nucala. They can also suggest ways to help reduce side effects.

Mild side effects

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

Mild side effects of Nucala 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.

Besides the side effects listed, people who used Nucala for chronic rhinosinusitis with nasal polyps also reported having additional mild side effects. (These side effects weren’t reported by people who used Nucala to treat other conditions.) These additional side effects included:

  • diarrhea
  • dryness in the nose
  • fever
  • joint pain
  • pain affecting the tongue, tonsils, throat, or roof of the mouth
  • skin rash

Serious side effects

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

A serious side effect of Nucala that has been reported is shingles.

Allergic reaction

Some people may have an allergic reaction to Nucala, including severe allergic reaction. This side effect occured after the drug was approved for use.

Symptoms of a severe allergic reaction may include:

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 continue your Nucala treatment.

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 Nucala, they may have you switch to a different treatment.

Find answers to some commonly asked questions about Nucala.

Is Nucala an immunosuppressant?

Yes, Nucala may be considered an immunosuppressant. The drug works by inhibiting (stopping) the activity of a certain immune system protein that increases the level of eosinophils. Eosinophils are a type of white blood cell that protects the body against foreign substances. They do this by causing inflammation in the body. But this can also lead to asthma and other inflammatory conditions.

By blocking the protein that increases the levels of eosinophils, Nucala reduces inflammation, which helps treat your condition.

Talk with your doctor or pharmacist to learn more about how Nucala works. You can also see the “How Nucala works” section.

Is Nucala like Dupixent or Cinqair?

Nucala, Dupixent, and Cinqair are similar medications. They belong to the same group of drugs and are all biologic medications. (Biologics are made using parts of living organisms.)

These drugs are all used to treat eosinophilic asthma, but Nucala and Dupixent treat other conditions as well.

Nucala, Dupixent, and Cinqair are all given by injection. Nucala and Dupixent are given as an injection under the skin, while Cinqair is given as an intravenous (IV) infusion (an injection into a vein over a period of time).

To learn more about how Nucala compares with other medications, talk with your doctor.

Are weight gain, weight loss, and hair loss possible side effects of Nucala?

No, Nucala should not cause weight changes or hair loss. These were not reported as side effects in the drug’s studies.

Other drugs prescribed to treat conditions that Nucala also treats may cause these side effects. For example:

  • Corticosteroids such as prednisone, which may be prescribed to treat asthma, can cause weight gain if used long term.
  • Other medications used to treat eosinophilic granulomatosis with polyangiitis, including methotrexate (Trexall, others), can cause hair loss.

If you’re concerned about weight changes or hair loss, talk with your doctor.

Can Nucala be used for chronic obstructive pulmonary disease (COPD)?

In some cases, yes. Nucala is not approved by the Food and Drug Administration (FDA) to treat COPD. But the drug may be prescribed off-label for this use. (With off-label use, doctors prescribe a drug for a purpose other than what it’s approved for.)

Recent studies have shown that Nucala may help treat COPD in some people. However, more research is needed about the drug’s use for this condition.

If you have questions about using Nucala for COPD, talk with your doctor.

There are important considerations to discuss with your doctor before you start treatment with Nucala. This includes a discussion of your medical history and other medications you may take.

Interactions

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

Before using Nucala, be sure to tell your doctor about all medications you take, including prescription and over-the-counter kinds. Also, describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause with Nucala.

There currently aren’t any medications or supplements known to interact with Nucala. But this doesn’t mean drug interactions with Nucala won’t be recognized in the future. For example, new medications may be approved that interact with Nucala.

For this reason, you should still tell your doctor and pharmacist about any medications you take besides Nucala. This way, they can check for any new interactions during your treatment.

For information about drug-condition interactions, see the “Warnings” section.

Nucala and alcohol

There’s no known interaction between alcohol and Nucala.

It’s important to note that Nucala is prescribed to treat certain conditions caused by excess inflammation (swelling and damage), and alcohol is known to increase inflammation in your body. Drinking alcohol may worsen the symptoms of your condition. This may make Nucala appear to not work as effectively to treat your condition.

Talk with your doctor if you have questions about consuming alcohol with Nucala, including whether alcohol could worsen symptoms of your condition.

Pregnancy and breastfeeding

It’s not known whether it’s safe to receive Nucala injections while pregnant. Drugs similar to Nucala can pass into the placenta over time during pregnancy, especially during the second and third trimesters. If you’re pregnant or planning to become pregnant, talk with your doctor about the risks and benefits of using Nucala.

It’s also not known whether breastfeeding is safe during Nucala treatment. If you’re breastfeeding or planning to breastfeed, talk with your doctor before using Nucala.

Warnings

Nucala can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Nucala is a good treatment option for you.

Talk with your doctor about your health history before you use Nucala. Be sure to tell them if any of the following factors apply to you:

Note: You should not use Nucala for an asthma attack. If you have an asthma attack, use your rescue inhaler as directed by your doctor. If you have questions about what to do during an asthma attack, talk with your doctor.

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

What to do in case you use too much Nucala

Call your doctor if you think you’ve injected too much Nucala. 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 questions about whether Nucala is right for you, talk with your doctor or pharmacist.

Questions you may want to ask include:

  • If I’m unable to give myself Nucala injections at home, will I need to pay a separate cost to get injections from a healthcare professional?
  • What happens if my insurance coverage changes while I’m prescribed Nucala?
  • How will we measure whether Nucala is working well for my condition?

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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.