Omalizumab

Pronunciation: oh-ma-LIZ-oo-mab.

Generic name: omalizumab
Brand names: XOLAIR
Drug class: Anti-immunoglobulin E (anti-IgE) monoclonal antibody
Form: Single-dose vial, pre-filled syringe, or pre-filled autoinjector/pen depending on country and product
Route: Subcutaneous injection
Legal status: Prescription-only biologic medicine

Supply Rules Vary

Trade names by country: United States · United Kingdom · Canada · Australia

Australia: XOLAIR (4) · Full directory

What omalizumab is and how it works

Omalizumab is a biologic medicine that binds immunoglobulin E (IgE), reducing IgE-driven allergic signalling. Current approved uses include selected allergic asthma, chronic rhinosinusitis with nasal polyps, chronic spontaneous urticaria, and—in the United States—reduction of allergic reactions after accidental exposure to one or more foods in eligible people. (1) (2) (3)

The approved uses and minimum ages differ by country. Omalizumab is add-on or preventive treatment; it does not replace emergency treatment for an asthma attack or food-allergy reaction. A specialist must confirm eligibility and the injection plan.

Mechanism of action: how omalizumab works

Omalizumab is a recombinant humanised IgG monoclonal antibody that binds free human IgE, reducing IgE available to bind high-affinity receptors and down-regulating allergic inflammatory signalling. (1) (3)

What omalizumab is used for

Allergic asthma

Omalizumab may be added to existing treatment for eligible people with inadequately controlled, IgE-mediated allergic asthma. Exact severity, age, testing, lung-function, background-treatment, IgE, and weight criteria are country-label specific. (1) (3)

Chronic rhinosinusitis with nasal polyps

It may be used as add-on maintenance treatment for eligible adults whose nasal-polyps disease remains inadequately controlled; local indication wording and background nasal treatment apply. (1) (3)

Chronic spontaneous urticaria

It may be used for eligible people whose chronic spontaneous hives remain symptomatic despite H1-antihistamine treatment. It is not a general treatment for every form of urticaria. (1) (2) (3)

IgE-mediated food allergy in the United States

The current US label includes reduction of allergic reactions, including anaphylaxis risk, after accidental exposure to one or more foods in eligible adults and children. People must continue avoiding the relevant foods and retain their emergency action plan; omalizumab is not emergency treatment. (1) (2)

Before taking omalizumab

Do not take / not appropriate for

Do not receive omalizumab after a severe hypersensitivity reaction to omalizumab or a product ingredient unless the responsible specialist determines otherwise under the exact local label. (all products) (1) (3)
Do not use omalizumab to treat a sudden asthma attack, status asthmaticus, or an allergic emergency after food exposure. (all indications) (1) (2)

Tell your clinician about

Any previous anaphylaxis, including reactions to medicines, foods, biologics, latex, or unexplained triggers.
Current asthma control, recent emergency treatment, and every inhaler, corticosteroid, antihistamine, or other background medicine.
A parasitic-worm infection, travel or residence that increases parasite exposure, fever, rash, joint pain, numbness, or tingling.
Pregnancy, plans for pregnancy, breastfeeding, or any vaccine or other biologic treatment.
Whether the intended patient or caregiver can recognise anaphylaxis, inject the exact device correctly, and obtain emergency help.

(1) (2) (3)

How to take omalizumab

Omalizumab is injected under the skin according to an indication- and patient-specific schedule set by the specialist.
Treatment begins in a healthcare setting with observation for anaphylaxis. Home administration is considered only after the prescriber applies the current product criteria and provides device and emergency training.
Do not change the dose, number of injections, interval, device, or injection setting yourself.
Do not abruptly reduce or stop corticosteroids, asthma controllers, antihistamines, food avoidance, or prescribed emergency medicines.

(1) (2) (3)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4)

Missed dose

Contact the prescribing clinic for rescheduling instructions. Do not give an extra injection or alter the next dose or interval without specialist advice.

Overdose

If the wrong strength, number of injections, or product may have been administered, contact the prescribing service or poison-information service urgently. Seek emergency care immediately for any allergic-reaction symptoms. (1) (3)

Side effects

Effects vary with indication and age. Anaphylaxis is uncommon but can be life-threatening and can occur after any dose, including after long-established treatment.

Injection-site reaction

What to notice: Pain, redness, swelling, warmth, bruising, hardness, burning, or itching where the injection was given.

What to do: Tell the treatment team if severe, worsening, persistent, or accompanied by general allergic symptoms. (2) (3)

Headache, joint or limb pain, tiredness, or upper-airway symptoms

What to notice: Symptoms and frequency depend on the treated condition and age group.

What to do: Discuss persistent or troublesome symptoms with the prescribing team rather than stopping treatment yourself. (1) (2)

Fever, joint pain, and rash syndrome

What to notice: Fever, rash, swollen glands, and muscle or joint pain, often developing days after an injection.

What to do: Contact the prescribing team promptly for assessment. (1) (2)

Eosinophilic or vasculitic illness

What to notice: Worsening breathing, rash, chest symptoms, nerve pain, numbness, tingling, weakness, or other new systemic symptoms.

What to do: Seek prompt medical assessment, especially during corticosteroid reduction. (1) (3)

Serious warnings

Anaphylaxis — emergency

Symptoms: Wheezing or breathing difficulty, throat or tongue swelling, throat tightness, trouble swallowing, hives, flushing, faintness, weak or rapid heartbeat, or a feeling of impending danger.

Action: Use prescribed emergency medicine immediately when the action plan directs and call emergency services. Anaphylaxis can occur after any dose and may begin outside the clinic. (1) (2) (3)

Acute asthma attack — emergency

Symptoms: Severe or rapidly worsening breathlessness, inability to speak normally, poor response to the prescribed reliever, drowsiness, or blue/grey lips.

Action: Follow the asthma emergency plan and obtain emergency care. Omalizumab does not relieve an acute attack. (1) (2)

Allergic reaction after accidental food exposure — emergency

Symptoms: Breathing difficulty, throat symptoms, collapse, widespread hives, repetitive vomiting, or other action-plan criteria after exposure.

Action: Use epinephrine/adrenaline and call emergency services as directed by the individual emergency plan. Omalizumab is not rescue treatment and does not replace food avoidance. (1) (2)

Interactions

Medicine or test	Effect	Action
Other asthma, allergy, or urticaria medicines	Omalizumab is generally add-on treatment; stopping background therapy abruptly can worsen disease or cause corticosteroid withdrawal problems.	Change other treatment only through the responsible specialist's staged plan. (1) (2)
Allergen immunotherapy, other biologics, vaccines, and immunomodulating medicines	Evidence and timing may be product- and indication-specific, and combined treatment can complicate adverse-reaction assessment.	Give the specialist and pharmacist a complete treatment and vaccination list before administration. (3)
Laboratory total IgE testing	Total IgE levels rise during treatment and can remain elevated after stopping; repeat values should not be used casually to recalculate asthma or food-allergy dosing.	Dose determination and reassessment must follow the exact indication-specific product algorithm. (1) (3)

Pregnancy, breastfeeding, kidney/liver function, age

Children and adolescents

Minimum age, indication, device, and self-administration permissions differ. A specialist must use the exact local product information; adult criteria cannot be extrapolated to a child. (1) (3)

Pregnancy and breastfeeding

Discuss benefits, disease-control risks, pregnancy data, and breastfeeding with the specialist. Do not stop asthma control treatment abruptly because uncontrolled disease can also be harmful. (1) (3)

People at risk of parasitic infection

Tell the prescriber about relevant travel, residence, symptoms, or previous infection because omalizumab may affect resistance to some helminth infections. (1) (3)

Monitoring

Before starting

Confirm the exact diagnosis, indication, minimum age, background treatment, and local eligibility criteria.
For label-defined indications, record pretreatment total IgE and body weight using the correct product algorithm.
Assess previous anaphylaxis, emergency-plan readiness, asthma control, comorbidities, infection risk, and all medicines.
Select the exact formulation, device, injection setting, observation plan, and trained administrator.

During treatment

Observe for anaphylaxis according to current product and local clinical protocols and maintain readiness for emergency treatment.
Reassess disease control, exacerbations or accidental reactions, background-treatment needs, adverse effects, adherence, and continued eligibility.
Reassess whether home administration remains appropriate and whether the patient or caregiver can use the device and emergency plan correctly.
Do not infer treatment failure or recalculate treatment from an on-treatment total IgE value outside the product algorithm.

(1) (2) (3)

Storage

Keep the exact product refrigerated and protected from light as directed by its packaging. Do not freeze, shake, heat, or use a device with an uncertain storage history. Follow the product-specific permitted room-temperature window and single-use sharps-disposal instructions.

Professional information

Clinician-facing context only. Use the current local indication, dosing table, formulation/device instructions, anaphylaxis protocol, and background-disease guideline.

All regions

Indication: Any omalizumab use

Dose summary: No universal dose is displayed. Determine dose, interval, injection count, device, and reassessment from the exact indication, age, pretreatment IgE where applicable, body weight where applicable, and current local label.

Renal context: Renal or hepatic impairment, frailty, comorbidity, infection risk, and concomitant therapy require individual assessment; do not infer a web-based adjustment. (1) (3)

Mechanism of action

Hepatic guidance

Use local product information and specialist judgement; this page does not provide impairment-specific dosing.

Overdose note

Medication errors require product identification, dose reconstruction, anaphylaxis readiness, poison-centre or specialist advice, and supportive monitoring. (1) (3)

Frequently asked questions

Can omalizumab replace my reliever inhaler or epinephrine/adrenaline?

No. Omalizumab is preventive or add-on treatment. Continue the prescribed asthma or food-allergy emergency plan and carry emergency medicines as directed. (1) (2)

Can omalizumab cause anaphylaxis after I have used it safely for months?

Yes. Serious allergic reactions can occur after any dose, including after established treatment. Know the symptoms and follow the emergency plan immediately. (1) (2)

Can I inject omalizumab at home?

Only if the prescriber confirms that the exact product and patient meet current criteria and provides injection and anaphylaxis training. Some patients or products are not suitable for home use. (1) (2)

What is the mechanism of action of omalizumab?

What is the generic name of Omalizumab?

The generic name is omalizumab. It is sold under brand names including XOLAIR. (1) (2) (3)

What class of drug is omalizumab?

Omalizumab is classed as: Anti-immunoglobulin E (anti-IgE) monoclonal antibody. (1) (2) (3)

References

XOLAIR (omalizumab) — prescribing informationU.S. Food and Drug Administration · United States · dated 2024 · accessed 2026-07-22 · source 1
Omalizumab Injection: MedlinePlus Drug InformationMedlinePlus, U.S. National Library of Medicine · United States · accessed 2026-07-22 · source 2
Xolair 75 mg solution for injection in pre-filled syringe — Summary of Product Characteristicselectronic Medicines Compendium (UK) · United Kingdom · accessed 2026-07-22 · source 3
XOLAIR omalizumab 300 mg solution for injection pre-filled syringe — ARTG 429450Therapeutic Goods Administration · Australia · dated 2024-09-04 · accessed 2026-07-22 · source 4

Brand names by country

Single-ingredient omalizumab names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

Xolair75 mg/.5mL, 150 mg/mL, 150 mg.2mL, 300 mg/2mL · genentech, inc.

United Kingdom

Xolair (3)current licensed product · 75 mg product example · Novartis Pharmaceuticals UK Ltd

Canada

XOLAIR

Australia

XOLAIR (4)current register product example · 300 mg · Novartis Pharmaceuticals Australia Pty Ltd

View brands in additional countries.