Health Information

Omalizumab Injection

  • Home
  • Health Information
Omalizumab Injection 

En Español (Spanish Version)

(oh mah lye zoo' mab)


Omalizumab injection may cause a serious or life-threatening allergic reaction. An allergic reaction may occur immediately after an injection of omalizumab is given or 24 hours or longer after the injection is given. People who did not have an allergic reaction to their first dose of omalizumab may have an allergic reaction after they receive another dose of the medication.

Tell your doctor if you have ever had an allergic reaction after receiving an injection of omalizumab. You should not receive omalizumab injection if you have ever had an allergic reaction to the medication.

You will receive each injection of omalizumab in your doctor's office. You will stay in the office for some time after you receive the medication so your doctor can watch you closely. Tell your doctor if you experience any of the following symptoms of an allergic reaction: wheezing or difficulty breathing, shortness of breath, cough, chest tightness, dizziness, fainting, fast or weak heartbeat, anxiety, feeling that something bad is about to happen, flushing, itching, hives, feeling warm, swelling of the throat or tongue, throat tightness, hoarse voice, or difficulty swallowing. Get immediate emergency medical attention if you experience any of these symptoms after you leave your doctor's office.

Your doctor will give you the manufacturer's patient information sheet (Medication Guide) each time you receive an injection of omalizumab. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website ( or the manufacturer's website to obtain the Medication Guide.

Talk to your doctor about the risks of using omalizumab.

WHY is this medicine prescribed?

Omalizumab injection is used to decrease the number of asthma attacks (sudden episodes of wheezing, shortness of breath, and trouble breathing) in people with allergic asthma (asthma caused by inhaling substances such as dander, pollen, and dust mites) whose symptoms are not controlled with inhaled steroids. Omalizumab is in a class of medications called monoclonal antibodies. It works by blocking the action of IgE, a natural substance in the body that causes the symptoms of allergic asthma.

HOW should this medicine be used?

Omalizumab injection comes as a solution (liquid) to inject subcutaneously (under the skin). It is usually injected in a doctor's office once every 2 weeks or every 4 weeks. You may receive one or more injections at each visit, depending on the dose prescribed by your doctor.

It may take some time before you feel the full benefit of omalizumab. Call your doctor if your asthma symptoms worsen. Talk to your doctor so that you know what to do if you have an asthma attack or breathing problems while using omalizumab. Omalizumab will not relieve the symptoms of a sudden asthma attack.

Omalizumab injection may be used along with other medications for asthma. Do not decrease your dose of any other asthma medication or stop taking any other asthma medication that has been prescribed by your doctor, unless your doctor tells you to do so. Your doctor may want to decrease your dose of some other asthma medications gradually.

Are there OTHER USES for this medicine?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before using omalizumab injection,

  • tell your doctor and pharmacist if you are allergic to any medications.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.
  • tell your doctor if you have any other medical conditions and if you are being treated with allergy immunotherapy (allergy shots; a series of injections given regularly to prevent the body from developing allergic reactions to specific substances).
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while using omalizumab, call your doctor.
  • talk to your doctor about whether there is a risk that you will develop a hookworm, roundworm, whipworm, or threadworm infection (infection with worms that live inside the body). If you are at high risk of developing this type of infection, using omalizumab may increase the chance that you will actually become infected. Most of these infections are rare in the United States, but if you are at risk of developing an infection, your doctor can suggest ways to prevent infection and will monitor you carefully during your treatment.

What SPECIAL DIETARY instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do IF I FORGET to take a dose?

If you miss an appointment to receive an injection of omalizumab, you should call your doctor as soon as possible. The missed dose should be given as soon as it can be rescheduled.

What SIDE EFFECTS can this medicine cause?

Omalizumab injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • pain, redness, swelling, warmth, burning, stinging, bruising, hardness (bump), or itching in the place omalizumab was injected
  • pain, especially in the joints, arms, or legs
  • tiredness
  • ear pain

Omalizumab may increase the risk of developing cancer, including breast, skin, parotid (salivary gland, located near the mouth), and prostate cancer. Talk to your doctor about the risks of using this medication.

Omalizumab may cause other side effects. Call your doctor if you have any unusual problems while using this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at ] or by phone [1-800-332-1088].

What should I know about STORAGE and DISPOSAL of this medication?

Your doctor will store this medication in his or her office.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

What OTHER INFORMATION should I know?

Keep all appointments with your doctor.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking or have taken omalizumab.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Brand Names

  • Xolair®

Medication Information

The information contained in this tool is intended as an educational aid only. It is not intended as medical advice for individual conditions or treatment. It is not a substitute for a medical exam, nor does it replace the need for services provided by medical professionals. Talk to your doctor, nurse or pharmacist before taking any prescription or over the counter drugs (including any herbal medicines or supplements) or following any treatment or regimen. Only your doctor, nurse, or pharmacist can provide you with advice on what is safe and effective for you.

The use of this tool is at your sole risk. These products are provided "AS IS" and "as available" for use, without warranties of any kind, either expressed or implied. HCA makes no representation of warranty as to the accuracy, reliability, timeliness, usefulness or completeness of any of the information contained in the products. Additionally, HCA makes no representation or warranties as to the opinions or other service or data you may access, download or use as a result of use of this tool. ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE OR USE ARE HEREBY EXCLUDED. HCA does not assume any responsibility or risk for your use of this tool.

By searching using the form below, you hereby agree to the above conditions.


If you are not certain how to spell the term, try using the first few letters to get a list of possible matches. (i.e. as for Aspirin)