Reviewed by: HU Medical Review Board | Last Reviewed: May 2022 | Last updated: May 2023
Xolair® (omalizumab) is an injectable medicine used to treat moderate-to-severe persistent asthma in people ages 6 and up whose asthma is not well-controlled with inhaled corticosteroids. You should have a skin or blood allergy test to confirm your allergies before taking Xolair.1
Do not take Xolair if you are having an asthma attack. Use a rescue inhaler instead.1
How does Xolair work?
Xolair works by blocking IgE. 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 biologic drug. Biologics are drugs made from living cells. These cells can come from parts of the blood, proteins, viruses, or tissue. The process of making biologics turns products made from cells into drugs that can prevent, treat, and cure disease. These are different from most traditional drugs. Traditional drugs are made from chemicals in a lab. Their ingredients are not directly derived from living cells.1,4
What are the possible side effects?
The most common side effects of Xolair in adults and children 12 and older include:1,4
- Joint pain, especially in the arms and legs
- Feeling tired
- Bone fractures
- Pain or discomfort in the ears
The most common side effects of Xolair in children ages 6 to 11 include:1,4
- Swelling inside the nose, throat, or sinuses
- Throat infection
- Ear infection
- Stomach pain
- Stomach infection
- Nose bleeds
Xolair may also cause serious side effects, including:1,4
- Blood vessel inflammation
- Fever, muscle aches, and rash
- Parasitic infection
- Heart and circulation problems
Xolair has a boxed warning, the strictest warning from the US Food and Drug Administration (FDA). It has this warning because it may cause a severe allergic reaction, including anaphylaxis. This reaction can occur after the first dose or after many doses. It may also occur right after a Xolair injection or days later. Anaphylaxis is a life-threatening condition that can lead to death. Call 9-1-1 right away if you have any signs of an allergic reaction:1,4
- Wheezing, shortness of breath, cough, chest tightness, or trouble breathing
- Low blood pressure, dizziness, fainting, rapid or weak heartbeat, or anxiety
- Flushing, itching, hives, or feeling warm
- Swelling of the throat or tongue, throat tightness, hoarse voice, or trouble swallowing
Your doctor will monitor you for signs of an allergic reaction while you are receiving Xolair and for a period after treatment.
These are not all the possible side effects of Xolair. Talk to your doctor about what to expect when taking Xolair. You also should call your doctor if you have any changes that concern you when taking Xolair.
Other things to know
When starting treatment, Xolair is given in your doctor’s office by your doctor or nurse. Your doctor will decide if you or your caregiver can learn how to give Xolair at home. Pre-filled syringes are available to those who self-inject.1,4
Before taking Xolair, tell your doctor if you have:1,4
- Have seasonal allergies or allergies to latex or food
- Have sudden breathing problems
- Have ever had anaphylaxis
- Have or have had a parasitic infection
- Have or have had cancer
There is not enough data to know if Xolair is safe to take while pregnant or breastfeeding. Before taking Xolair, tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.1,4
Before beginning treatment for asthma, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.
For more information, read the full prescribing information of Xolair.