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How does Xolair work?

Medically reviewed by Carmen Pope, BPharm. Last updated on Feb 23, 2024.

Official Answer by Drugs.com

Xolair (omalizumab) is an antibody that may be used to treat allergic asthma that is moderate-to-severe, persistent, and not adequately controlled by inhaled corticosteroids, in adults and children aged 6 and over who have had a positive skin test to an allergen or who react to an allergen that is present in their environment year-round.

Xolair is also approved for:

How does Xolair work?

Xolair works by inhibiting the binding of IgE to IgE receptors on mast cells and basophils. Mast cells and basophils are specific cells of the immune system that contain histamine and heparin. As soon as IgE binds to an IgE receptor it causes the release of histamine and heparin from the cell.

Histamine is a chemical that has many inflammatory effects in the body. It contracts the smooth muscle tissue in the lungs, uterus, and stomach; dilates blood vessels causing an increase in permeability and a lowering of blood pressure; stimulates the secretion of gastric acid in the stomach; and speeds up the heart rate. Histamine also causes symptoms such as a runny nose, watery eyes, tissue swelling, itchy skin, and hives.

Because histamine contracts the breathing tubes it can cause wheezing or make it harder to breathe. Histamine is also one of the main chemicals involved in anaphylaxis, a severe and often fatal allergic response to a previously encountered allergen.

Heparin is an anticoagulant that slows the formation of blood clots.

By inhibiting the binding of IgE to the IgE receptor, Xolair prevents the release of histamine and heparin and also reduces the number of IgE receptors on basophils.

IgE levels are increased in people with allergic asthma when they inhale allergens such as pet dander or dust mites which is why Xolair is effective at treating allergic asthma. Xolair will not treat an acute asthma attack or status asthmaticus.

93% of people with moderate-to-severe chronic urticaria have increased total IgE levels.

IgE levels are also increased in people with Ig-E-mediated food allergies when they come into contact with a food allergen.

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Does Xolair cause weight gain?

There were no reports of weight gain or weight loss in clinical trials with Xolair. Weight gain is more likely to be caused by corticosteroids, hydroxyzine, or antihistamines that may also be used to treat allergic asthma or hives. Continue reading

What is omalizumab's mechanism of action?

The omalizumab mechanism of action is designed to target IgE (immunoglobulin E), an antibody produced by the immune system. It works by inhibiting the binding of the IgE antibody to IgE receptors on cells that can lead to inflammation and worsened allergic symptoms. Continue reading

Can Xolair be self-administered at home?

Yes, you or your caregiver can learn how to give Xolair at home if you and your doctor agree that self-injection is appropriate. For children 12 years of age and older, the Xolair prefilled syringe or autoinjector may be self-injected under adult supervision. For children 1 to 11 years of age, only the Xolair prefilled syringe should be used and injected by a caregiver, as the autoinjector is not intended for this age group. Continue reading

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