Karen Berger, PharmD, is a community pharmacist and medical writer/reviewer.

David Snyder, PharmD, BCPP, is a board-certified clinical pharmacist and psychopharmacology expert at McLean Hospital in Belmont, Massachusetts.

In some cases, a severe and life-threatening allergic reaction called anaphylaxis may occur after Xolair is administered. Anaphylaxis can lead to death. Symptoms can include low blood pressure, dizziness, fainting, anxiety, feeling of "impending doom," wheezing, shortness of breath, cough, chest or throat tightness, swelling of the throat or tongue, flushing, itching, hives, hoarseness, or trouble swallowing. This can occur anytime, from after the first dose, to after a year or more of Xolair treatment. Because of this risk, Xolair must be started in a healthcare setting. A healthcare provider will closely monitor your reaction after the drug is given. The healthcare provider who administers Xolair is trained in managing anaphylaxis. You should always be alert to the above-mentioned symptoms of anaphylaxis and seek emergency medical care if symptoms occur.

Xolair (omalizumab ) is a prescription drug injected subcutaneously (under the skin of the thigh, stomach, or outer arm if given by a caregiver). Xolair is available as a prefilled syringe and as single-dose vials.

Xolair is used to treat:

Xolair works by blocking the action of a substance in the body that causes asthma, polyps, and hives. Xolair is in a drug class called monoclonal antibodies.

Brand Name(s): Xolair

Therapeutic Classification: Monoclonal antibody (Anti-IgE antibody)

Administration Route: Subcutaneous (under the skin)

Dosage Form(s): Solution, powder for solution

The Food and Drug Administration (FDA) approved Xolair for:

Xolair is not used to treat acute bronchospasm (narrowing of the airways that causes wheezing and shortness of breath), acute asthma attacks, other allergic conditions, or other rashes or hives.

Before you start Xolair, make sure to read the prescription label and the information leaflet that comes with your prescription. Consult your healthcare provider if you have any questions.

Use Xolair exactly as directed by your healthcare provider, usually once every two or four weeks. You may receive the injection by a healthcare provider or be trained to self-administer.

For the administration of Xolair:

People who have asthma or polyps will have a blood test for immunoglobulin E (IgE) before starting Xolair. This test measures immunoglobulin E antibodies and shows what the body is reacting to. The test results will help your healthcare provider determine the proper Xolair dosage and frequency. People with CSU do not require this blood test.

Do not change the dose or stop taking your other medications unless instructed by your healthcare provider. Because Xolair dose is based on weight, notify your healthcare provider if you gain or lose weight as you may need a dosage change.

Your symptoms may not improve right away. If your symptoms worsen quickly or if you feel like your asthma medications are not working, contact your healthcare provider.

Ask your healthcare provider if you have any questions or concerns about Xolair.

Store the prefilled syringes in the refrigerator (36 to 46 degrees Fahrenheit) in the original carton. The syringe can be taken out and put back in the refrigerator if needed, but the total time out of the refrigerator cannot be more than two days. Do not use Xolair if it has been exposed to temperatures above 77 degrees Fahrenheit. Do not freeze Xolair, and do not use it if it has been frozen.

The vial form of Xolair is for administration by a healthcare provider in the medical setting and should be stored in the refrigerator.

Sometimes Xolair is used off-label for indications that are not FDA approved. In some cases, healthcare providers may prescribe Xolair off-label to people with severe food allergies.

Xolair is absorbed in the body slowly, taking seven or eight days to reach its highest level. Symptoms will not improve right away. It may take a few weeks for symptoms to improve.

Like other medications, Xolair can cause side effects. Tell your healthcare provider about any side effects you experience while taking this medication.

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 1-800-FDA-1088.

Common side effects of Xolair include:

Call your healthcare provider right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

While many people tolerate Xolair well, long-term or delayed side effects are possible. Some long-term side effects can be mild, such as: 

Moderate long-term side effects can include: 

Severe long-term side effects may include: 

Xolair may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

You may need to use caution when taking Xolair if you are 65 years or older. Studies did not include many older adults, so consult your healthcare provider for guidance. There are no specific guidelines recommended for people with kidney or liver problems. People with kidney or liver conditions should consult their healthcare provider for medical advice before using Xolair.

People who are pregnant, planning to become pregnant, or are breastfeeding, should consult their healthcare provider before using Xolair.

If you miss a dose of Xolair, call your healthcare provider as soon as possible for instructions.

No reports of toxicities related to Xolair intravenous dosing have been established.

If you think you or someone else may have overdosed on Xolair, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Xolair, call 911 immediately.

It is very important that your doctor check your or your child's progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it. Blood tests and other exams may be needed to check for unwanted effects.

If you stop receiving omalizumab injections, your symptoms can be expected to return.

You may not see immediate improvement in your asthma after omalizumab treatment begins. It takes time for the medicine to work. It is important to continue your omalizumab injections until your doctor tells you otherwise.

This medicine may cause a serious type of allergic reaction called anaphylaxis, which can be life-threatening and requires immediate medical attention. Anaphylaxis may occur right away or up to 4 days after receiving this medicine. Tell your doctor right away if you or your child have a rash, cough, chest tightness, trouble breathing, lightheadedness, dizziness, fainting, rapid or weak heartbeat, anxiety, flushing, itching, hives, feeling warm, swelling of the throat or tongue, throat tightness, hoarseness, or trouble swallowing after receiving this medicine.

A rare but serious condition called eosinophilia (increased white blood cells in the body) may occur while you are receiving this medicine. A condition called vasculitis (inflammation of the blood vessels) may also be present. Eosinophilia can be serious and requires immediate medical attention. Tell your doctor right away if you or your child have worsening lung symptoms, rash or bruising of the skin, fever, chest pain, or burning, tingling, or numbness in the hands and feet after receiving this medicine.

Your doctor will ask you or your child to remain at the healthcare facility or clinic for at least 2 hours after each injection to watch for immediate side effects that can be serious.

Some patients who are receiving this medicine may have fever, rash, or muscle or joint pain. Tell your doctor right away if you or your child have any of these symptoms.

Using this medicine may increase your risk of getting certain cancers or infections. Talk to your doctor if you or your child have concerns about this risk.

The needle cap of the prefilled syringe contains dry natural rubber (a derivative of latex), which may cause allergic reactions in people who are sensitive to latex. Tell your doctor if you have a latex allergy before receiving this medicine.

Before you have any medical tests, tell the medical doctor in charge that you are taking this medicine. The results of some tests may be affected by this medicine.

Xolair is not appropriate for everyone. You should not take this medication if you are allergic to omalizumab or any of the inactive ingredients in Xolair. 

Other people who should not take Xolair include:

Xolair may be prescribed with caution in some people, only if the healthcare provider determines it is safe. This includes:

Xolair has not been studied in drug interaction studies. Therefore, no significant interactions are known with other drugs.

Xolair is a monoclonal antibody used for allergic asthma, polyps, or hives. Other monoclonal antibodies include:

People who take Xolair for asthma also take other medications for asthma. A rescue inhaler, also known as a short-acting beta-agonist, is used for acute asthma exacerbations or before exercise in people with exercise-induced bronchospasm. Examples of rescue inhalers are:

Long-acting beta-agonists, also called LABAs, should never be taken alone. A LABA may increase the risk of death if it is not taken with a steroid. Therefore, a LABA should always be taken with an inhaled steroid. This can be done either as two individual separate products or as a combination product. An example of a LABA is Serevent (salmeterol). 

An inhaled corticosteroid (ICS) can be taken alone or with a LABA. Examples of inhaled steroids are:

There are some combination inhaled drugs that contain both a steroid and a LABA. Some examples of steroid/LABA combination inhalers include:

Trelegy Ellipta contains three drugs: fluticasone, which is a steroid; umeclidinium, which is an anticholinergic drug; and vilanterol, which is a LABA. 

There are also other drugs that can be prescribed to control asthma symptoms, for example, oral medications like Singulair (montelukast) or oral steroids, such as prednisone. 

This list is a list of drugs also prescribed for asthma. It is NOT a list of drugs recommended to take with Xolair. Ask your pharmacist or a healthcare provider if you have questions.

Xolair is a monoclonal antibody that can be used in:

Xolair works by blocking the action of a substance in the body that can cause asthma, polyps, and hives.

No drug interaction studies have been done with Xolair, and no significant interactions are known.

Xolair takes seven or eight days to reach its highest level in the body. It may take several weeks for symptoms to improve.

Common side effects include injection site reaction, cough and cold symptoms, headache, muscle and joint pain, tiredness, dizziness, nausea, itching, stomach pain, nosebleed, ear infection, skin irritation, fractures, fever, and anxiety. Serious side effects may occur as well. Symptoms, such as hives, difficulty breathing, and swelling of the face, lips, tongue, or throat, indicate a severe allergic reaction and require emergency attention.

Your healthcare provider will tell you how long to take Xolair.

Before you take Xolair, discuss your medical history and all medication you take with your healthcare provider. When taking Xolair, follow your healthcare provider’s instructions for use. Read the information leaflet that comes with your prescription. Ask your healthcare provider if you have any questions. Be sure to get all of the bloodwork that your healthcare provider orders before and during treatment. 

Before self-injecting Xolair, or before a caregiver injects it, be sure that you or your caregiver have been fully trained. It can feel intimidating to give yourself an injection, but after several times, you will feel more comfortable, and you will begin to feel more confident in your ability to inject yourself. 

Your healthcare provider will advise you if you need to change your other medications. Do not stop taking your steroid medications unless instructed by your healthcare provider.

Xolair does not treat acute bronchospasm or acute exacerbation of asthma. Always carry a fast-acting rescue inhaler. It can be helpful to have two rescue inhalers, so you can keep one inhaler at home and one inhaler at work or school. Check the expiration date and how many puffs are remaining on a regular basis. Call in refills to the pharmacy several days ahead to ensure you never run out.  

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

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DailyMed. Label: xolair - omalizumab injection, solution.

Prescribers’ Digital Reference. Omalizumab - drug summary.

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