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Xolair in the Treatment of Asthma

Xolair Safety and Side Effects


Updated June 10, 2014

Xolair in the Treatment of Asthma
American College of Allergy, Asthma and Immunology
Updated June 10, 2014

What is Xolair?

Xolair (omalizumab) is an injectable medication used to treat moderate to severe allergic asthma. It can be used in people 12 years and older who still have uncontrolled asthma despite typical asthma medications, such as inhaled steroids. Injections are given in the doctor’s office every 2 to 4 weeks, depending on a person’s weight and allergic antibody (IgE) level. Check to see if your asthma is controlled by taking the asthma control test.

Xolair is a monoclonal anti-IgE antibody, which binds to IgE in the bloodstream, allowing the body to remove them. The drug is produced in mice, and therefore contains approximately 5% mouse protein (it does not appear that an allergy to mouse protein causes problems for people receiving Xolair). This prevents IgE from attaching to mast cells, and binding to allergens, which ultimately results in the release of histamine and other chemicals. It is these chemicals which cause worsening of asthma and other allergy symptoms.

Xolair has been shown to decrease asthma attacks, improve spirometry values, improve overall quality of life for people with asthma, and reduce the amount of corticosteroids needed. Generally, it can take a few months of injections for Xolair to begin to work, and the medication can be very expensive. Xolair is not a cure for asthma; symptoms would be expected to worsen a few months after Xolair therapy is stopped.

What Risks are Associated with Xolair?

Xolair currently has a “black box” warning, which a precautionary statement given to the medication by the Food and Drug Administration (FDA). This warning has come about as a result of reports of people experiencing anaphylaxis after receiving Xolair. During clinical development, the rate of anaphylaxis was less than 0.1% (1 in 1,000 people receiving Xolair injections). Since Xolair has been available for prescription use, this rate has risen to 0.2% (2 people per 1,000 Xolair injections).

While there are no reports of fatal anaphylaxis as a result of Xolair, some cases have been serious, and potentially life-threatening. For this reason, the FDA requires that people receiving Xolair be monitored in the physician’s office for a period of time after their injections. The actual amount of time is determined by the physician, although I monitor patients for 30 to 60 minutes after injections (and for 2 hours after the first Xolair injection).

People who receive Xolair should watch out for the following symptoms of anaphylaxis, which could occur up to 24 hours (or longer) after the injection:

  • Wheezing, shortness of breath, coughing, chest tightness or trouble breathing
  • Low blood pressure, dizziness, fainting, rapid or weak heartbeat
  • Flushing, itching, hives or swelling
  • Nausea, vomiting, diarrhea or abdominal pains
  • Swelling of the throat, tongue, lips, or eyes
  • Throat tightness, hoarse voice, trouble swallowing
  • Sudden severe sneezing, severe runny nose or nasal congestion
  • Anxiety or feeling of panic

Should any of these symptoms occur, it is important to notify your physician immediately. Many physicians prescribe injectable epinephrine for a person to carry for 24 hours after their Xolair injection, to use in the case of anaphylaxis.

During clinical development, rates of cancer were slightly higher in people receiving Xolair (0.5%) compared to people receiving placebo injections (no active medication) (0.2%). The types of cancers seen in people receiving Xolair include various types, and include breast cancer, skin cancers and prostate cancer. It is not yet known what the potential long-term effects of Xolair use may have on people who are prone to getting cancer (such as the elderly).

While it would appear that Xolair has potentially severe side effects, it must be remembered that anaphylaxis and cancer formation occurred only in a very small number of patients. It is still not known why these side effects occur, although studies are ongoing to determine the reason. It is also important to realize that uncontrolled asthma can lead to severe complications, including death. And medications used to treat asthma attacks, such as oral and injected corticosteroids, have a long list of side effects with long term use.

It is therefore important to discuss with your doctor the risks and benefits of taking Xolair for asthma that is not controlled on typical asthma medications.

Can Xolair be used for other Allergic Conditions?

Currently, Xolair is only indicated by the FDA to treat asthma. However, numerous studies have been conducted, and others are ongoing, to use medications like Xolair to treat other allergic diseases, such as food allergy, latex allergy, drug allergy, insect allergy and chronic hives. It is important to realize that the use of Xolair for these conditions is not consistent with FDA dosing indication.

Want to keep learning? Read the patient information sheets on Xolair from the FDA.


Aaronson DW. The “Black Box” Warning and Allergy Drugs. J Allergy Clin Immunol. 2006;117:40-4.

Berger WE. Monoclonal Anti-IgE Antibody: A Novel Therapy for Allergic Airways Disease. Ann Allergy Asthma Immunol. 2002; 88:152-161.

Xolair Package Insert. Genentech and Novartis Pharmaceuticals. 2007.

DISCLAIMER: The information contained in this site is for educational purposes only, and should not be used as a substitute for personal care by a licensed physician. Please see your physician for diagnosis and treatment of any concerning symptoms or medical condition.

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