Prescription medication · Anti-IgE Monoclonal Antibody
omalizumab
Also sold as Xolair. Xolair can treat moderate to severe asthma in people 6 years and older who have allergies.
Data updated 2026-05-15
- 79,748
- FDA reportsOften reported
- Rx
- Availability
omalizumab (Xolair) is a prescription Anti-IgE Monoclonal Antibody. Xolair can treat moderate to severe asthma in people 6 years and older who have allergies.
Xolair is a medicine that can help with asthma, nasal polyps, food allergies, and chronic hives. It works by blocking a substance in your body called IgE.
Verify with FDA → · CMS NADAC pricing →
What it does
Xolair can treat moderate to severe asthma in people 6 years and older who have allergies.
Common side effects
Joint pain, General pain, Leg pain
Key warnings
Xolair can cause a severe allergic reaction called anaphylaxis, even after the first dose or after you have been taking it for a year or more.
The sections below are summarized in plain English from omalizumab's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Xolair is a special type of medicine called an anti-IgE monoclonal antibody. It blocks immunoglobulin E (IgE) in your body. IgE is a substance that causes allergic reactions and inflammation.
Side Effects (from patient reports)
Based on 79,748 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for omalizumab, by number of reports
- Asthma
Asthma
11,601 reports
- Urticaria
Urticaria
10,326 reports
- Dyspnoea
Dyspnoea
9,876 reports
- Cough
Cough
6,767 reports
- Pruritus
Pruritus
5,942 reports
- Fatigue
Fatigue
5,824 reports
- Malaise
Malaise
5,429 reports
- Wheezing
Wheezing
5,239 reports
- Headache
Headache
5,206 reports
- Pneumonia
Pneumonia
4,979 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for omalizumab each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where omalizumab sits
omalizumab has more FDA adverse-event reports than 82% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is omalizumab; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 79,748 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
79,748
Reports Mentioning Death
2,390
3.0% of reports — not proof of cause
Hospitalization Reports
15,129
Top Indication
Asthma
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | ASTHMA | 11,601 |
| 2 | URTICARIA | 10,326 |
| 5 | DYSPNOEA | 9,876 |
| 7 | COUGH | 6,767 |
| 8 | PRURITUS | 5,942 |
| 9 | FATIGUE | 5,824 |
| 10 | MALAISE | 5,429 |
| 11 | WHEEZING | 5,239 |
| 12 | HEADACHE | 5,206 |
| 13 | PNEUMONIA | 4,979 |
| 14 | PAIN | 4,103 |
| 15 | ANAPHYLACTIC REACTION | 3,984 |
| 16 | NASOPHARYNGITIS | 3,844 |
| 17 | ARTHRALGIA | 3,625 |
| 18 | HYPERSENSITIVITY | 3,398 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Xolair can cause a severe allergic reaction called anaphylaxis, even after the first dose or after you have been taking it for a year or more. This reaction can cause trouble breathing, low blood pressure, fainting, hives, and swelling of the throat or tongue. Because of this risk, your doctor should give you Xolair in a healthcare setting where they can treat anaphylaxis. Watch for signs of anaphylaxis after each Xolair injection and seek immediate medical care if symptoms occur.
Common Questions
Can Xolair cure my asthma?
Can I use Xolair for a sudden asthma attack?
How long does it take for Xolair to work?
Will Xolair get rid of my nasal polyps?
Do I still need to avoid foods I am allergic to while taking Xolair?
Can Xolair completely prevent allergic reactions to food?
Can I stop taking my other allergy medicines while on Xolair?
What should I do if I have an allergic reaction after getting a Xolair injection?
Will Xolair cause me to gain weight?
Can I give myself Xolair injections at home?
What are the common side effects of omalizumab?
What drug class is omalizumab?
What pregnancy or breastfeeding source fields are listed for omalizumab?
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Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for omalizumab: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 79,748.
- montelukast Δ 1,389 reports · Leukotriene Receptor Antagonist 78,359reports
- diclofenac Δ 2,417 reports · Nonsteroidal Anti-Inflammatory Drug (NSAID) 82,165reports
- golimumab Δ 2,874 reports · TNF-Alpha Inhibitor (Biologic) 82,622reports
- sulfasalazine Δ 3,478 reports · Disease-Modifying Antirheumatic Drug (DMARD) 76,270reports
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 3.00%.
- imiquimod Δ 0.01 pts · 2,179 reports · Immune Response Modifier (Topical) 2.98%death share
- biotin Δ 0.05 pts · 29,879 reports · Vitamin B7 Supplement 3.05%death share
- conjugated estrogens Δ 0.08 pts · 57,675 reports · Conjugated Estrogen 3.08%death share
- guanfacine Δ 0.09 pts · 7,386 reports · Central Alpha-2 Agonist 3.09%death share
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
FDA bioequivalence and label-record context for narrow therapeutic index medicines
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for omalizumab
The FDA label for omalizumab (sold under brand names such as Xolair) classifies it as a prescription-only medication in the Anti-IgE Monoclonal Antibody class. Xolair can treat moderate to severe asthma in people 6 years and older who have allergies. Official labeling lists 24 commonly reported side effects, including Joint pain, General pain, Leg pain.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 79,748 voluntary reports. Interaction data is drawn directly from FDA-approved prescribing information. Acquisition-cost data is surveyed weekly by CMS and updated as manufacturers report changes.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: December 2, 2025
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages