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How long before Xolair starts working?

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:

Xolair is also approved to treat:

Xolair is administered by injection under the skin (subcutaneously) once every two to four weeks. The dosage of Xolair is based on body weight. Xolair is absorbed slowly, with peak concentrations being reached approximately 7 to 8 days after administration.

Although some improvement in symptoms may be noted after a few weeks, it may take several months for Xolair to start working properly in your body. Significant improvements have been noted in trials in asthma patients of four months, in trials of people with urticaria of three months, and in trials of people with Ig-E-mediated food allergies of 16 to 20 weeks.

Related questions

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.

Xolair forms stable Xolair/IgE complexes which are more slowly excreted from the body than free IgE. This means that total serum IgE levels (bound and unbound) will show an increase in laboratory testing; however, serum-free IgE levels are decreased within an hour of injection, and decreases of greater than 96% have been reported.

References

Read next

How does Xolair affect IgA and IgE levels?

Xolair demonstrates a highly selective effect on immunoglobulin levels in the body, with significant impacts on IgE but no meaningful effect on IgA or other immunoglobulin classes. This selective action is central to omalizumab's therapeutic value in treating IgE-mediated allergic conditions while minimizing broader immune system disruption.

Continue reading

Does Xolair cause hair loss?

Hair loss (alopecia), has been reported in Xolair clinical studies in at least 2% of people with chronic hives. Hair loss has also been noted in several case reports with Xolair. The hair loss effect appears to be transient, lasting from 3 to 4 months. Due to limited data, the exact cause of hair loss or how often it occurs is not known. Continue reading

Does Xolair cause cancer?

Xolair is associated with a slightly higher risk of cancer, but cancer specialists have determined that this does not mean that Xolair causes cancer. Research has shown that cancer occurred in 20 out of 4127 trial participants (0.5% of Xolair-treated study volunteers) and 5 out of 2236 (0.2%) of people who were assigned an inactive treatment. Continue reading

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