Drug side effects
omalizumab Side Effects
The reactions most often reported to the FDA for omalizumab (also sold as Xolair), with demographics, serious outcomes, and reporting trends.
Data updated 2026-05-15
- 79,748
- FAERS reports
Data from the FDA Adverse Event Reporting System (FAERS), 2004 to 2025. A FAERS report records a temporal association, not proof of cause. See our methodology for how figures are compiled and de-duplicated.
The most commonly reported side effects of omalizumab come from 79,748 reports to the FDA, broken down here by frequency, patient demographics, and serious outcomes.
This page analyzes 79,748 reports to the FDA Adverse Event Reporting System (FAERS) for omalizumab (Xolair): the reactions reported most often, who reported them, serious outcomes such as hospitalization, and year-over-year trends. A FAERS report does not prove the drug caused the effect, and report volume tracks how widely a drug is used, not how likely an effect is for any one person. Educational information, not medical advice.
Total Reports
79,748
Reports Mentioning Death
2,390
3.0% of reports — not proof the medicine caused the death
Hospitalizations
15,129
19.0% of reports
Top Indication
Asthma
Most Reported Adverse Reactions
Who Reports Side Effects
Gender Distribution
Age Distribution
Reporting Trend by Year
Reactions in Death Reports
Top reactions reported in 2,390 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| DEATH | 1,455 |
| ASTHMA | 301 |
| PNEUMONIA | 179 |
| DYSPNOEA | 165 |
| MALAISE | 129 |
| FATIGUE | 111 |
| ASTHENIA | 101 |
| COUGH | 99 |
| MYOCARDIAL INFARCTION | 86 |
| WHEEZING | 85 |
| HEART RATE INCREASED | 81 |
| WEIGHT DECREASED | 81 |
| CHRONIC OBSTRUCTIVE PULMONARY DISEASE | 67 |
| FALL | 67 |
| FORCED EXPIRATORY VOLUME DECREASED | 63 |
| LUNG DISORDER | 61 |
| HEADACHE | 60 |
| RESPIRATORY FAILURE | 59 |
Reactions in Hospitalization Reports
Top reactions in 15,129 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| ASTHMA | 5,346 |
| DYSPNOEA | 4,226 |
| COUGH | 3,043 |
| PNEUMONIA | 2,699 |
| MALAISE | 2,262 |
| WHEEZING | 2,208 |
| FATIGUE | 2,039 |
| URTICARIA | 1,872 |
| HEADACHE | 1,727 |
| WEIGHT DECREASED | 1,613 |
| NASOPHARYNGITIS | 1,605 |
| PYREXIA | 1,573 |
| PRURITUS | 1,338 |
| PAIN | 1,320 |
| CHEST DISCOMFORT | 1,313 |
| INFLUENZA | 1,307 |
| PRODUCTIVE COUGH | 1,285 |
| BLOOD PRESSURE INCREASED | 1,234 |
| HYPERSENSITIVITY | 1,216 |
Nearby, Related Medications
What the FAERS Data Reveals About omalizumab Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 79,748 voluntary reports linked to omalizumab and its brand equivalents (Xolair), spanning 2004 through 2025. Of those, 2,390 (3.0%) listed death as an outcome and 15,129 (19.0%) involved hospitalization. The most common indication reported alongside adverse events was Asthma.
Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 73% were female and 26% male; age distribution skews toward 45-64, with 15,541 reports in that bracket. The single most reported reaction is asthma with 11,601 submissions, followed by urticaria and dyspnoea.
How to read these numbers
FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice, speak with a licensed clinician about any side-effect concerns.
Drugs With a Similar FAERS Report Volume
Other medications with a total FDA adverse-event report count closest to omalizumab's 79,748.
Read our methodology - how this data is sourced, computed, and verified.