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What is severe asthma

This page is specifically for patients who have been prescribed Nucala. If you are not a patient who has already been prescribed Nucala, please return to the public website.

What makes my asthma severe

  • One of the ways that asthma can differ is in its severity. In general, patients with ‘severe’ asthma find it difficult to control their daily asthma symptoms
  • Severe asthma patients may continue to have asthma attacks, even when they are taking high doses of prescribed asthma medications

What does refractory mean?

Refractory means that your asthma is difficult to control and/or is resistant to treatment

What are eosinophils?


Eosinophils are a type of white blood cell found throughout your body, which play an important role in your immune system

Scientists have discovered that when eosinophils move from your blood into your lungs, they can cause your airways to become inflamed, increasing the risk of a severe asthma attack

Nucala is a registered trademark of the GlaxoSmithKline group of companies

Adverse events should be reported. Reporting forms and information can be found at or search for MHRA Yellowcard in the Google Play or Apple App store. Adverse events should also be reported to GlaxoSmithKline on 0800 221 441.