Nucala side effects and how to avoid them

Nucala is the brand name for an FDA-approved medication manufactured by GlaxoSmithKline (GSK) taken to reduce symptoms and prevent flare-ups of the following inflammatory autoimmune disorders:

  • Asthma in adults and children 6 years of age and over (Nucala is an add-on maintenance treatment for patients with severe eosinophilic asthma)
  • Eosinophilic granulomatosis with polyangiitis (EGPA) in adults
  • Hypereosinophilic syndrome (HES) in adults and children aged 12 years and over

While Nucala is generally well tolerated, there are some potential side effects that people should be aware of. The most common side effects of Nucala include injection site reactions. Less common, but more serious side effects, can include severe allergic reactions.

Learn more about the side effects of Nucala and what you can do to avoid them.

How do I take Nucala?

The medication is injected under your skin (subcutaneous injection) once every 4 weeks. The injection can be given by your doctor or another healthcare professional. It can also be administered at home using a prefilled syringe or prefilled autoinjector, either by yourself or by a caregiver. Nucala reduces how much inflammation you have in your body, easing your symptoms and making flare-ups of more severe symptoms less likely.

How does Nucala work?

The active ingredient in Nucala is called mepolizumab. Mepolizumab is a type of medicine called a humanized monoclonal antibody that has been designed to target the substance in your body that triggers inflammation.

Your immune system triggers inflammation in your tissues through a complex process with a number of steps. Mepolizumab works by blocking one of these steps. It attaches to and blocks a signaling molecule released by your white blood cells called interleukin. This stops interleukin from activating the next step in the inflammatory process and reduces how much inflammation you have in your body.

Inflammation in the body is an important part of how asthma develops, and eosinophils are one of the many cells in your body involved in inflammation. Blocking interleukin helps to reduce the production of eosinophils, reduce inflammation and help to treat asthma.

What are the most common side effects of Nucala?

The most common side effects caused by Nucala compared to placebo include:

  • Injection site reactions – pain, itching, a burning feeling, redness, and swelling
  • Urinary tract infections
  • Eczema
  • Headaches
  • Back pain
  • Tiredness

Serious side effects of Nucala

In rarer instances, Nucala can cause more serious side effects. These include:

  • Severe allergic reactions (hypersensitivity) to the medication which can trigger anaphylaxis. This can also cause rashes and hives to break out on your skin, as well as a fall in blood pressure, feeling lightheaded, and dizzy, and swelling of your face, mouth, and throat, breathing problems
  • Red or blistering skin rash and a burning or tingling sensation in your body
  • Reactivation of herpes zoster infection (shingles) if you have previously had the infection

These are not all the possible side effects of Nucala. Call your healthcare provider for medical advice about your side effects. Report negative side effects of prescription drugs to the FDA. Visit, or call 1-800-FDA-1088.

Nucala warnings and precautions

Nucala is not intended to relieve the sudden onset of asthma symptoms. If you experience a sudden onset of symptoms or have a severe asthma attack, use a rescue inhaler or other medicine you have been prescribed for sudden and severe symptoms.

Nucala should not be given to:

  • Adults under 18 years of age to treat eosinophilic granulomatosis with polyangiitis
  • Children under 12 years of age to treat hypereosinophilic syndrome
  • Children under 6 years of age to treat asthma
  • Treat sudden breathing problems

Nucala is not suitable for everyone. Do not take Nucala if you are allergic to the active ingredient mepolizumab or any of the other ingredients in Nucala.

Talk to your doctor about your medical conditions before taking Nucala if you:

  • Are taking any medications that contain steroids or corticosteroids for your asthma
  • Have a parasitic infection (roundworm or tapeworm)
  • Are over 65 years of age
  • Are pregnant or are planning to become pregnant
  • Are breastfeeding or are planning to breastfeed – It is not known if this medication passes into breast milk

Tell your healthcare provider about all the medicines you take, including prescription drugs and over-the-counter medicines, vitamins, and herbal supplements. You are also advised to read the complete drug information provided to you with your medication.

Does Nucala cause weight gain?

Weight gain is not a side effect of Nucala that has been reported during clinical trials.

Does Nucala weaken the immune system?

Nucala reduces the number of eosinophils, a type of white blood cells in the body. White blood cells normally help the body fight infections, but a reduction in their number can increase the risk of developing infections.

How long do Nucala side effects last?

Nucala is injected every 4 weeks. In this regard you should expect any side effects of Nucala to last at least 4 weeks.

What are the long-term side effects of Nucala?

Patients using Nucala long-term developed bronchitis, lower respiratory tract infections, dyspnea, nasal congestion, pharyngitis, nasopharyngitis, and viral respiratory tract infection as long-term side effects.

Does Nucala cause shingles?

Nucala can cause the reactivation of herpes zoster infection (shingles) if you have previously had the infection.

Dioes Nucala cause hair loss?

Hair loss is not a side effect reported in clinical trials of Nucala.

How to avoid Nucala side effects

The best way to avoid side effects is to take Nucala as directed by your doctor. Follow your doctor’s instructions carefully and do not take more or less than prescribed.

If you experience any side effects, talk to your doctor or pharmacist. They may be able to recommend ways to help reduce or prevent some of the side effects.

1. Stick to the recommended dosage

Take your prescribed dose of Nucala that has been recommended by your healthcare professional. Do not take more or less than prescribed.

2. Monitor your blood sugar levels

If you have diabetes, it is important to monitor your blood sugar levels closely while taking Nucala. Check your blood sugar levels as directed by your doctor and report any changes to your doctor immediately.

3. Drink plenty of fluids

Drink eight to 10 glasses of water or fluids every day to help prevent dehydration, which can make side effects worse.

4. Avoid alcohol

Avoid drinking alcohol while taking Nucala as it can increase your risk of mild, moderate, and severe side effects.

5. Don’t skip meals

Eating regular meals and snacks will help to prevent low blood sugar levels (hypoglycemia).

6. Check your feet

If you have diabetes, check your feet for any cuts, sores, or redness regularly. Tell your doctor if you experience any problems with your feet while taking Nucala.

7. Know the signs and symptoms of Nucala side effects

Signs and symptoms of side effects include severe allergic reactions. If you experience any of these symptoms speak to your doctor for medical advice.

8. Tell your doctor about all medications you’re taking

Be sure to tell your doctor about all other medications you’re taking, including over-the-counter drugs, vitamins, and herbal supplements, as they can interact with Nucala.

9. Get regular medical check ups

It is important to get regular medical check ups and monitor your medical conditions. Your doctor will monitor your side effects and may adjust your dose of Nucala as needed.

Medically reviewed

A medical professional has reviewed this article.

Jamie Winn, PharmD
Jamie Winn, PharmD

Jamie Winn, PharmD

Medical Writer & Reviewer

Jamie Winn, PharmD

Medical Writer & Reviewer

Dr. Jamie Winn received his Doctor of Pharmacy in 2002 from the University of South Carolina College of Pharmacy, Columbia, SC. Jamie is a medical reviewer for NiceRx.

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Sources (2)

  1. FDA - highlights of prescribing information for Nucala

  2. Nucala official website - Risks & side effects

The content on this website is intended for information purposes only. It does not constitute medical advice. The information on this website should not be relied upon and is not a substitute for professional medical advice. You should always speak to your doctor regarding the risks and benefits of any treatment.