mepolizumab Side Effects
Also known as: Nucala
Analysis of 47,215 adverse event reports submitted to the FDA from 2008 to 2025.
Total Reports
47,215
Death-Related
3,552
7.5% of reports
Hospitalizations
15,164
32.1% of reports
Top Indication
Product Used For Unknown Indication
Most Reported Adverse Reactions
Who Reports Side Effects
Gender Distribution
Age Distribution
Reporting Trend by Year
Reactions in Death Reports
Top reactions reported in 3,552 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| DEATH | 1,677 |
| OFF LABEL USE | 889 |
| PAIN | 719 |
| CONFUSIONAL STATE | 685 |
| MATERNAL EXPOSURE DURING PREGNANCY | 685 |
| PEMPHIGUS | 680 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 677 |
| INFUSION RELATED REACTION | 670 |
| CONDITION AGGRAVATED | 666 |
| SYNOVITIS | 664 |
| SYSTEMIC LUPUS ERYTHEMATOSUS | 654 |
| PRODUCT USE IN UNAPPROVED INDICATION | 651 |
| LUNG DISORDER | 649 |
| DYSPNOEA | 648 |
| WOUND | 647 |
| GASTROOESOPHAGEAL REFLUX DISEASE | 642 |
| PSORIATIC ARTHROPATHY | 642 |
| GLOSSODYNIA | 641 |
| RASH | 638 |
| DRUG INEFFECTIVE | 636 |
Reactions in Hospitalization Reports
Top reactions in 15,164 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| ASTHMA | 6,643 |
| DYSPNOEA | 5,330 |
| WHEEZING | 3,748 |
| PNEUMONIA | 2,743 |
| THERAPEUTIC PRODUCT EFFECT INCOMPLETE | 2,457 |
| LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES | 2,287 |
| COUGH | 2,205 |
| DRUG INEFFECTIVE | 2,048 |
| HOSPITALISATION | 1,977 |
| SLEEP DISORDER DUE TO A GENERAL MEDICAL CONDITION | 1,633 |
| CONDITION AGGRAVATED | 1,408 |
| PAIN | 1,386 |
| FATIGUE | 1,365 |
| MALAISE | 1,356 |
| OBSTRUCTIVE AIRWAYS DISORDER | 1,159 |
| OFF LABEL USE | 1,108 |
| LUNG DISORDER | 1,094 |
| HEADACHE | 1,087 |
| PRODUCT DOSE OMISSION ISSUE | 1,013 |
| ASTHENIA | 1,003 |
Nearby — Related Medications
What the FAERS Data Reveals About mepolizumab Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 47,215 voluntary reports linked to mepolizumab and its brand equivalents (Nucala), spanning 2008 through 2025. Of those, 3,552 (7.5%) listed death as an outcome and 15,164 (32.1%) involved hospitalization. The most common indication reported alongside adverse events was Product Used For Unknown Indication.
Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 68% were female and 32% male; age distribution skews toward 45-64, with 7,567 reports in that bracket. The single most reported reaction is asthma with 12,416 submissions, followed by dyspnoea and wheezing.
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.
Read our methodology — how this data is sourced, computed, and verified.