Xolair (omalizumab)

Xolair (omalizumab) is an anti-IgE antibody. Xolair is approved to treat people ages 6 years and up with moderate to severe persistent asthma and a proven allergy to a year-round allergen.1 You should have a skin or blood allergy test to confirm your allergies. Xolair is intended to treat people whose asthma is not controlled with inhaled corticosteroids. It is also approved to treat people with chronic hives without a known cause and people with nasal polyps. It is made by Genentech Inc. Xolair is taken by injection.

Do not take Xolair if you are having an asthma attack.1 Use a rescue inhaler (short-acting beta agonist) instead.

How does Xolair work?

Xolair works by blocking IgE.1 IgE is an antibody that is responsible for many allergy symptoms. Xolair prevents IgE from turning on inflammatory cells called mast cells and basophils. This reduces symptoms such as wheezing, coughing, swelling, itching, and runny nose.2,3 Xolair is a monoclonal antibody made using biotechnology.1

How is Xolair taken?

Xolair is taken by an under-the-skin injection.1 The dose and frequency depends on your IgE levels and body weight. Your IgE levels are checked with a blood test. The injection is given in your health care provider’s office.4

What are the risks of taking Xolair?

Xolair can cause a life-threatening allergic reaction, called anaphylaxis.2 The reaction can happen the first time you take Xolair, but it can also happen after you have taken many doses. You will have to wait in your health care provider’s office after each injection in case of an immediate reaction. However, a reaction also can happen days later. If you have symptoms of an allergic reaction, go to the emergency department immediately. According to the product insert, signs of a serious reaction are:2

  • wheezing, breathlessness, cough, chest tightness, or trouble breathing
  • low blood pressure, dizziness, fainting, rapid or weak heartbeat, anxiety, or feeling of
    “impending doom”
  • flushing, itching, hives, or feeling warm
  • swelling of the throat or tongue, throat tightness, hoarse voice, or trouble swallowing

Studies of Xolair indicate that anaphylaxis occurs in 0.1% to 0.2% of people who take this medication.1

Some people who took Xolair had chest pain, heart attack, blood clots, temporary weakness on one side of the body, slurred speech, or altered vision.2 Whether Xolair caused these symptoms is not known.

What are the possible side effects of taking Xolair?

Common symptoms of taking Xolair are: pain in the arms and legs, dizziness, feeling tired, skin rash, bone fractures, injection site reactions, sore throat, and earache.2 You may have a fever, muscle aches, or rash within five days of taking Xolair.

People who take Xolair may have an increased risk of infections, including a higher risk of a worm (parasitic) infection and certain types of cancer.2 Tell your healthcare provider if you have had cancer or parasitic infections before. This is not an exhaustive list of side effects that could occur with Xolair and others may occur. Please make sure to discuss this with your doctor.

Black box warning

Anaphylaxis has been reported to occur after administration of Xolair. See full prescribing information for details.

These are not all the possible side effects of Xolair. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with Xolair.

Are there people who should not take Xolair?

Do not take Xolair if you are having an asthma attack.1 Use a rescue inhaler instead.

Tell your health care provider about any other allergies you have, such as food or seasonal allergies.2 You should also mention if you have had any sudden breathing problems or anaphylaxis. Tell your health care provider about any prescription or over-the-counter medications and supplements that you take.

Xolair has not been well studied in pregnant or breastfeeding women.2 Little is known about whether this medication passes into breast milk. Talk to your doctor about if you become pregnant or wish to breastfeed while taking Xolair. A pregnancy registry has been set up. The purpose of the registry is to track the outcomes for women who take Xolair while pregnant. Results from the registry were published in 2015.5 Of 188 women who took Xolair during their first trimester, there was no apparent increase in major birth defects.

Is there a generic alternative to Xolair?

No, there is no generic alternative to Xolair.

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Written by: Sarah O'Brien | Last Reviewed: October 2021.