Omalizumab
Omalizumab is a monoclonal antibody that binds to immunoglobulin E (IgE), preventing it from attaching to receptors on mast cells and basophils. This reduces allergic inflammation and is used to treat moderate-to-severe allergic asthma, chronic rhinosinusitis with nasal polyps, and IgE-mediated food allergy.
Omalizumab is an injectable biologic that blocks IgE to suppress allergic reactions in asthma, nasal polyps, and food allergies.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- R03DX05
- RxNorm
- 302379
- Generic
- Omalizumab
- Class
- atc-r03d
- Brands
- Omlyclo, Xolair
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- prefilled syringe, injection
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Omalizumab is indicated for moderate-to-severe persistent allergic asthma in patients 6 years and older, chronic rhinosinusitis with nasal polyps (CRSwNP) in adults inadequately controlled with nasal corticosteroids, and IgE-mediated food allergy to reduce allergic reactions from accidental exposure.
Omalizumab is a recombinant DNA-derived IgG1 monoclonal antibody that binds to free IgE, inhibiting its interaction with FcεRI receptors on mast cells, basophils, and dendritic cells. This results in downregulation of FcεRI expression and suppression of the inflammatory cascade responsible for allergic responses.
Administered as subcutaneous injection every 2-4 weeks with dosing based on body weight and serum IgE level. Requires monitoring for anaphylaxis (most common within first 2 hours of administration), may increase susceptibility to parasitic infections, and should only be initiated by specialists experienced in managing severe allergic or asthmatic conditions.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy