What Xolair Side Effects Should I Be Concerned With?

Xolair and Asthma

An elderly patient talks with her doctor.

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Xolair is primarily used in the treatment of allergic asthma. The medication acts on the body's immune system to prevent an allergic response to trigger such as pollen or dust mites. Xolair interferes with the cascade of events that lead to asthma symptoms.

Your healthcare provider will usually recommend Xolair when you have moderate to severe asthma that has not responded to other treatments. It is not used as an initial asthma treatment and patients usually also have an elevated IgE level.

While Xolair (omalizumab) is generally well tolerated, there are a number of Xolair side effects you should consider, monitor for, and talk about with your healthcare provider if you experience them.

An elderly patient talks with her doctor.
Terry Vine / Getty Images

Xolair Side Effects - What Should I Be Concerned With About Xolair?

The most common Xolair side effects, and the percent of people who experienced them in clinical studies, are:

  • Injection site reactions (45%)-
  • Viral infections (23%)
  • Upper respiratory tract infections (20%)
  • Sinusitis (16%)
  • Headache (15%)
  • Pharyngitis (11%)

These Xolair side effects, however, were not seen more frequently than in those patients receiving a placebo injection.

There are a number of serious, potential Xolair side effects you should be aware of, though they only occur in less than 1% of patients taking Xolair. Xolair has been associated with:

  • Anaphylaxis - You will want to discuss with your healthcare provider if you need to be prescribed an emergency epinephrine pen in case this side effect occurs.
  • Serum sickness
  • Hives

Safety of Xolair

A study was started to examine the long-term safety of Xolair. While the study is not yet complete, the FDA issued a statement suggesting a potential risk of heart attack and stroke in patients taking Xolair. This has never been seen in prior studies, and the FDA did not make any changes based on the study's preliminary results. The FDA stated that it was not making any changes to the prescribing information for Xolair or advising patients to stop taking Xolair. Rather, FDA advised healthcare providers and their patients to be aware of these potential new risks and to report any problems encountered while taking Xolair to the FDA.

Talking With Your Healthcare Provider

You and your healthcare provider should have a conversation before starting a Xolair treatment program that covers, at a minimum, the following:

  1. The nature and the purpose of you being on Xolair.
  2. Risks of treatment including anaphylaxis and the other potential side effects mentioned in this article.
  3. Proper use of an epinephrine autoinjector in the event anaphylaxis occurs.
  4. The potential that Xolair may not benefit your asthma, but that you will be at some risk during treatment.
  5. Expected and possible outcomes of treatment with Xolair.
  6. Any alternative treatments to Xolair.
  7. Problems that may develop if you do not follow treatment regimen or instructions correctly.
  8. The need for regular follow-up and monitoring of asthma symptoms as well as notifying your healthcare provider of any unscheduled office or ER visits.

You should make sure that you fully understand the answers to these questions as well as any additional questions you have about your treatment.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Thomson NC, Chaudhuri R. Omalizumab: clinical use for the management of asthma. Clin Med Insights Circ Respir Pulm Med. 2012;6:27-40. doi:10.4137/CCRPM.S7793

Additional Reading
  • Approval History, Letters, Reviews, and Related Documents. XOLAIR (OMALIZUMAB) Review Document

  • Xolair Web Site. Xolair Prescribing Information

  • Lanier B. Unanswered clinical questions and speculation about the role of anti–immunoglobulin E in atopic and nonatopic disease. Allergy Asthma Proc 27:S37–S42, 2006)