Omalizumab Injection
Omalizumab Injection (Xolair, Xolair PFS) is an anti-IgE antibody given under the skin for allergic asthma, chronic rhinosinusitis with nasal polyps, IgE-mediated food allergy, and chronic spontaneous urticaria (long-lasting hives).
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
Omalizumab (Xolair) is an injected antibody that grabs IgE, the antibody that drives allergies, and keeps it off mast cells and other immune cells; on the market since about 2003, it is a specialist maintenance add-on for allergic asthma, nasal polyps and chronic hives (chronic spontaneous urticaria) not controlled by standard treatment, and it reduces reactions to accidental food exposure. Most people tolerate it well, noticing mild joint pain, tiredness or itching if anything. The boxed warning is anaphylaxis, a severe allergic reaction that can strike after the first dose or more than a year in, so get emergency help for wheezing, fainting, hives or throat or tongue swelling.
Clinical pearls
- Xolair never replaces your rescue inhaler or epinephrine, and it is not for an asthma attack or allergic reaction underway.
- Do not stop inhaled or oral steroids when Xolair starts, because your prescriber will lower them gradually.
- Joint pain, rash, fever and swollen glands 1 to 5 days after a dose can mean serum sickness, so report it.
- Mention any past anaphylaxis from foods or medicines, since it raises your risk and affects whether home injection is offered.
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
Xolair can cause anaphylaxis, a severe and potentially life-threatening allergic reaction. It can start with the first dose, but it can also happen after more than a year of treatment.
Signs include wheezing or trouble breathing, fainting, low blood pressure, hives, and swelling of the throat or tongue. Treatment is started in a healthcare setting, and you are watched afterward. Get immediate medical care if these symptoms occur. Home injection is only for carefully selected patients.
Patient information guide A plain-language walkthrough of Omalizumab Injection, written from its FDA label.
What Omalizumab Injection is used for
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Omalizumab Injection (Xolair) is approved for these conditions:
- Asthma: moderate to severe persistent allergic asthma in ages 6 and older, with a positive skin test or blood reactivity to a year-round allergen, when inhaled steroids are not enough.
- Chronic rhinosinusitis with nasal polyps: add-on maintenance treatment in adults 18 and older who did not respond well enough to nasal steroids.
- IgE-mediated food allergy: reduces allergic reactions, including anaphylaxis, from accidental food exposure in ages 1 and older. It is used along with avoiding the food.
- Chronic spontaneous urticaria: long-lasting hives in ages 12 and older who still have symptoms despite H1 antihistamines.
It is not for sudden asthma attacks, emergency allergic reactions, or other forms of hives.
How Omalizumab Injection works
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Omalizumab is an anti-IgE antibody. It blocks IgE from binding to receptors on mast cells, basophils and dendritic cells. Those receptors then decrease on the cells, which reduces allergy-driven inflammation.
In chronic spontaneous urticaria, it lowers free IgE, but how this helps hives is unknown.
Omalizumab Injection dosage
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Xolair is given by injection under the skin only. Most uses are every 2 or 4 weeks, and chronic spontaneous urticaria is every 4 weeks.
- For asthma, nasal polyps and food allergy, dose and timing are based on your pre-treatment total IgE level and body weight.
- For chronic spontaneous urticaria, dose does not depend on IgE level or weight.
- Treatment starts in a healthcare setting. Some patients may later use a prefilled syringe or autoinjector at home.
Follow your prescriber and the label for your exact dose and what to do about a missed dose.
Dosing details from the FDA-approved label
From the Omalizumab Injection prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Asthma
- XOLAIR 75 to 375 mg SC every 2 or 4 weeks, determined by serum total IgE level (IU/mL) measured before the start of treatment and body weight (kg)
- Adjust doses for significant changes in body weight during treatment
- Chronic Rhinosinusitis with Nasal Polyps
- XOLAIR 75 to 600 mg SC every 2 or 4 weeks, determined by serum total IgE level (IU/mL) measured before the start of treatment and body weight (kg)
- Adjust doses for significant changes in body weight during treatment
- IgE-Mediated Food Allergy
- XOLAIR 75 mg to 600 mg SC every 2 or 4 weeks, determined by serum total IgE level (IU/mL) measured before the start of treatment and body weight (kg)
- Adjust doses for significant changes in body weight during treatment
- Chronic Spontaneous Urticaria
- XOLAIR 150 or 300 mg SC every 4 weeks
- Dosing is not dependent on serum IgE level or body weight
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION For subcutaneous (SC) administration only. ( 2.2 , 2.3 , 2.4 , 2.5 ) See full prescribing information for administration instructions ( 2.6 , 2.7 , 2.8 ). Asthma : XOLAIR 75 to 375 mg SC every 2 or 4 weeks. Determine dose (mg) and dosing frequency by serum total IgE level (IU/mL), measured before the start of treatment, and body weight (kg). See the dose determination charts. ( 2.2 ) Chronic Rhinosinusitis with Nasal Polyps : XOLAIR 75 to 600 mg SC every 2 or 4 weeks. Determine dose (mg) and dosing frequency by serum total IgE level (IU/mL), measured before the start of treatment, and body weight (kg). See the dose determination charts. ( 2.3 ) IgE-Mediated Food Allergy : XOLAIR 75 mg to 600 mg SC every 2 or 4 weeks. Determine dose (mg) and dosing frequency by serum total IgE level (IU/mL), measured before the start of treatment, and body weight (kg). See the dose determination chart. ( 2.4 ) Chronic Spontaneous Urticaria : XOLAIR 150 or 300 mg SC every 4 weeks. Dosing in CSU is not dependent on serum IgE level or body weight. ( 2.5 ) 2.1 Overview of Dosage Determination Asthma, and Chronic Rhinosinusitis with Nasal Polyps, and IgE-Mediated Food Allergy Determine dosage of XOLAIR by serum total IgE level (IU/mL) measured before the start of treatment, and by body weight (kg). For patients with asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), and IgE-mediated food allergy, dosage determination should be based on the primary diagnosis for which XOLAIR is being prescribed. Adjust doses for significant changes in body weight during treatment. Refer to Tables 1 and 2 for the recommended dosage for treatment of asthma, Table 3 for treatment of CRSwNP, and Table 4 for treatment of IgE-mediated food allergy. Total IgE levels are elevated during treatment and remain elevated for up to one year after the discontinuation of treatment. Therefore, re-testing of IgE levels during XOLAIR treatment cannot be used as a guide for dose determination. Interruptions lasting less than one year: Dose based on serum IgE levels obtained at the initial dose determination. Interruptions lasting one year or more: Re-test total serum IgE levels for dose determination ( Table 1 or 2 for treatment of asthma, based on the patient's age, Table 3 for treatment of CRSwNP, and Table 4 for treatment of IgE-mediated food allergy).
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Omalizumab Injection side effects
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In asthma studies of people 12 and older, the most common side effects were:
Common side effects
- Joint pain (arthralgia)
- General pain, leg pain or arm pain
- Tiredness (fatigue)
- Dizziness
- Fractures
- Itching (pruritus)
- Skin inflammation (dermatitis)
- Earache
When to get medical help
- Get emergency help right away for wheezing or trouble breathing, fainting, low blood pressure, hives, or swelling of the throat or tongue. These can be signs of anaphylaxis (a severe allergic reaction).
- Call your doctor if you develop joint pain, rash, fever and swollen lymph nodes 1 to 5 days after an injection. These can look like serum sickness, and Xolair should be stopped.
- Call your doctor if your asthma stays uncontrolled or gets worse during treatment.
- Tell your doctor about a rash that looks like blood vessel inflammation, worsening lung symptoms, heart problems, or numbness or tingling. This is especially important when lowering oral steroids.
- Tell your doctor about any new lumps or other concerns, since cancers were seen more often in treated patients in clinical studies.
Seek emergency care for signs of anaphylaxis. Call your doctor for fever, rash, joint pain and swollen glands after an injection.
Omalizumab Injection warnings and precautions
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- Anaphylaxis (boxed warning): can be life-threatening and can occur even after a year or more of treatment. Most cases occur within the first three doses. A history of anaphylaxis raises the risk.
- Not for emergencies: do not use it for acute asthma symptoms or to treat an allergic reaction.
- Cancer: cancers were seen more often in treated patients in early studies. A later observational study showed similar rates, but a risk cannot be ruled out.
- Steroids: do not stop them abruptly. Your doctor will taper them.
- Eosinophilic conditions: rarely, serious eosinophilia with vasculitis-like features can occur, often when oral steroids are reduced.
- Serum sickness-like reaction: arthritis, rash, fever and swollen lymph nodes 1 to 5 days after an injection. Xolair should be stopped.
- Parasites: people at high risk of worm infections should be monitored.
Omalizumab Injection interactions
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No formal drug interaction studies have been done, but the label notes these points:
- Allergen immunotherapy: use together has not been evaluated for asthma, nasal polyps or food allergy.
- Immunosuppressive therapies: not studied together with Xolair in chronic spontaneous urticaria.
- Corticosteroids: do not stop them suddenly when starting Xolair for asthma or nasal polyps. Use with steroids in chronic spontaneous urticaria has not been evaluated.
Interactions listed in the FDA-approved label
From the Omalizumab Injection prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.
- XOLAIR (general drug interactions): No formal drug interaction studies have been performed with XOLAIR.
- Allergen immunotherapy: In patients with asthma, CRSwNP, and IgE-mediated food allergy, concomitant use with XOLAIR has not been evaluated.
- Immunosuppressive therapies: In patients with CSU, use of XOLAIR in combination with immunosuppressive therapies has not been studied.
Read the label’s full interactions text
7 DRUG INTERACTIONS No formal drug interaction studies have been performed with XOLAIR. In patients with asthma, CRSwNP, and IgE-mediated food allergy the concomitant use of XOLAIR and allergen immunotherapy has not been evaluated . In patients with CSU, the use of XOLAIR in combination with immunosuppressive therapies has not been studied. No formal drug interaction studies have been performed. ( 7 )
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Omalizumab Injection
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- Do not use it if you have had a severe allergic reaction to Xolair or its ingredients.
- Tell your doctor if you have ever had anaphylaxis from any cause.
- Pregnancy: Xolair may pass to the baby. A registry showed no increase in major birth defects or miscarriage, but more low birth weight, possibly related to more severe asthma. Poorly controlled asthma also carries risks in pregnancy.
- Breastfeeding: omalizumab is an antibody that may be in milk in small amounts. Discuss the benefits and risks with your doctor.
- Children: asthma use is established from age 6. Other uses start at age 1 (food allergy) or 12 (chronic spontaneous urticaria).
- Tell your doctor if you have a history of cancer or high cancer risk, or are at high risk of worm infections.
What Omalizumab Injection does in the body
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Xolair lowers free IgE (the unattached form) by more than 96% at recommended doses in asthma, within about 1 hour of the first dose. Total IgE rises because omalizumab-IgE complexes clear slowly. This effect is reversible and total IgE may stay above baseline for up to a year after stopping. In asthma, it reduces eosinophils and inflammatory chemicals such as IL-4, IL-5 and IL-13.
How your body processes Omalizumab Injection
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After an injection under the skin, about 62% of omalizumab reaches the bloodstream. Levels peak after about 7 to 8 days. Omalizumab is cleared by the same processes the body uses for antibodies, plus binding to IgE. Its half-life is about 26 days in asthma and 24 days in chronic spontaneous urticaria. Higher body weight increases clearance.
How to store Omalizumab Injection
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XOLAIR prefilled syringe and autoinjector should be shipped and stored under refrigerated conditions 2°C to 8°C (36°F to 46°F) in the original carton. Protect from direct sunlight. refrigerator if needed.
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Omalizumab Injection
53 supplements and herbal products have documented interactions with Omalizumab Injection in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Moderate · 52
- Minor · 1
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Omalizumab Injection: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Omalizumab Injection — the kind of thing our pharmacy team would talk through with you at the counter.
What is Xolair actually for?
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Can I use it if I'm having an asthma attack or allergic reaction?
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Why do I have to get the first doses in a clinic?
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What side effects should I expect?
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Can I stop my steroid medicine once I start?
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Is it safe in pregnancy?
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Is Omalizumab Injection available over the counter?
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When was Omalizumab Injection first available?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Omalizumab Injection on HelloPharmacist
Omalizumab Injection forms and strengths (how it comes)
Omalizumab Injection is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Injection
How this form is used
- Xolair is used for moderate to severe persistent allergic asthma, chronic rhinosinusitis with nasal polyps, IgE-mediated food allergy, and chronic spontaneous urticaria.
- Xolair is not for acute bronchospasm, status asthmaticus, or emergency treatment of allergic reactions.
- Xolair is for subcutaneous (under the skin) use only.
- Xolair therapy is started in a healthcare setting with observation afterward.
- Xolair prefilled syringe or autoinjector may be used outside a healthcare setting by selected patients or caregivers once therapy is established.
Omalizumab Injection on the U.S. market: products, makers and brands
How Omalizumab Injection appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
1 company lists 4 Omalizumab Injection product records with the FDA, mostly as injection; the earliest marketing or approval year on record is 2003. Brand names on the directory include Xolair, Omlyclo, Xolair PFS; the rest are generics.
How widely Omalizumab Injection is used (Medicaid data)
A general measure of how commonly Omalizumab Injection is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Omalizumab Injection is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Omalizumab Injection prescribed? Of the 1,601 medications we measure, Omalizumab Injection ranks #431 by Medicaid prescriptions — more than 73% of them.
Utilization by Omalizumab Injection product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
1 ML omalizumab 150 MG/ML Prefilled Syringe Most dispensed
Summed across the 2 of 3 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2058943
2 ML omalizumab 150 MG/ML Prefilled Syringe
Summed across the 2 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2663917
2 ML omalizumab 150 MG/ML Auto-Injector
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2663920
0.5 ML omalizumab 150 MG/ML Prefilled Syringe
Summed across the 2 of 3 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2058949
omalizumab 150 MG Injection
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1657209
1 ML omalizumab 150 MG/ML Auto-Injector
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2673760
0.5 ML omalizumab 150 MG/ML Auto-Injector
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2673762
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Omalizumab Injection, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 10 of 14 listed Omalizumab Injection NDCs with Medicaid activity.
Compare Omalizumab Injection products
A representative set of FDA-listed product records for Omalizumab Injection — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 75 mg/0.5 mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
| 150 mg/1.2 mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
| 150 mg/mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
| 300 mg/2 mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
Showing 4 of 4 products — FDA National Drug Code Directory. See every product, package size and price: browse all 4 Omalizumab Injection NDCs →
Omalizumab Injection side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Omalizumab Injection — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Omalizumab Injection in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Omalizumab Injection FDA approval history
How Omalizumab Injection went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Omalizumab Injection recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list one Omalizumab recall since July 2021, covering 2 product listings. It is still ongoing. A recall names specific lots from one company, so check the lot number on your own bottle rather than assuming every product is affected; your pharmacist can check whether your supply came from an affected lot.
- Xolair (omalizumab injection), 75 mg/0.5 ml, Rx only, Genentech, Inc., South San Francisco, CA 94080, NDC 50242-214-55 Lots: Lot: 3630004, Expires: 10/31/2025. FDA record D-0572-2025 →
- Xolair (omalizumab injection), 150 mg/ml, 1 auto-injector, Rx only, Genentech, Inc, South San Francisco, CA 9408, NDC: 50242-215-55. Lots: Lot: 3617756, Expires: 12/31/2025. FDA record D-0571-2025 →
Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 302379 3 dose forms · 9 strengths
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Dose form (SCDF) Auto-Injector RxCUI 2663919In current FDA listingsClinical drug / strength (SCD) 0.5 ML omalizumab 150 MG/MLRxCUI 26737621 ML omalizumab 150 MG/MLRxCUI 26737602 ML omalizumab 150 MG/MLRxCUI 2663920 -
Dose form (SCDF) Injection RxCUI 1657208In current FDA listingsClinical drug / strength (SCD) 150 MGRxCUI 1657209 -
Dose form (SCDF) Prefilled Syringe RxCUI 2058942No current FDA listingClinical drug / strength (SCD) 0.5 ML omalizumab 150 MG/MLRxCUI 20589490.5 ML omalizumab-igec 150 MG/MLRxCUI 27260101 ML omalizumab 150 MG/MLRxCUI 20589431 ML omalizumab-igec 150 MG/MLRxCUI 27260012 ML omalizumab 150 MG/MLRxCUI 2663917
Look up RxCUI 302379 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Omalizumab Injection supply and shortage status
Whether Omalizumab Injection is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Omalizumab Injection brand names
Omalizumab Injection is sold under 3 brand names in the FDA directory — Xolair, Omlyclo, Xolair PFS. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Omalizumab Injection: manufacturers and labelers
One company lists Omalizumab Injection products with the FDA. By number of product records, the largest are Genentech, Inc.. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Omalizumab Injection drug class (RxNorm)
Omalizumab Injection belongs to the Anti-IgE class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Omalizumab Injection page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Genentech, Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →