oseltamivir Side Effects
Also known as: Tamiflu
Analysis of 7,575 adverse event reports submitted to the FDA from 2004 to 2025.
Total Reports
7,575
Death-Related
1,149
15.2% of reports
Hospitalizations
2,529
33.4% 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 1,149 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| OFF LABEL USE | 328 |
| DRUG INEFFECTIVE | 257 |
| MULTIPLE ORGAN DYSFUNCTION SYNDROME | 234 |
| SEPSIS | 219 |
| DEATH | 211 |
| HYPONATRAEMIA | 211 |
| CONDITION AGGRAVATED | 203 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 201 |
| NAUSEA | 193 |
| VOMITING | 193 |
| ASCITES | 190 |
| STRESS | 190 |
| ABDOMINAL DISTENSION | 188 |
| APPENDICITIS | 186 |
| APPENDICOLITH | 184 |
| CARDIOGENIC SHOCK | 184 |
| ABDOMINAL PAIN | 181 |
| VENTRICULAR FIBRILLATION | 178 |
| CONSTIPATION | 174 |
| SOMNOLENCE | 152 |
Reactions in Hospitalization Reports
Top reactions in 2,529 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| OFF LABEL USE | 449 |
| DRUG INEFFECTIVE | 379 |
| PNEUMONIA | 268 |
| CONDITION AGGRAVATED | 232 |
| NAUSEA | 206 |
| INFLUENZA | 196 |
| VOMITING | 194 |
| DYSPNOEA | 190 |
| PRODUCT USE IN UNAPPROVED INDICATION | 171 |
| ABDOMINAL PAIN | 169 |
| SEPSIS | 166 |
| PYREXIA | 159 |
| ANAEMIA | 158 |
| HYPONATRAEMIA | 148 |
| MULTIPLE ORGAN DYSFUNCTION SYNDROME | 148 |
| PULMONARY EMBOLISM | 142 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 138 |
| SOMNOLENCE | 131 |
| ABDOMINAL DISTENSION | 128 |
| DRUG INTOLERANCE | 128 |
Nearby — Related Medications
What the FAERS Data Reveals About oseltamivir Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 7,575 voluntary reports linked to oseltamivir and its brand equivalents (Tamiflu), spanning 2004 through 2025. Of those, 1,149 (15.2%) listed death as an outcome and 2,529 (33.4%) 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, 51% were female and 48% male; age distribution skews toward 18-44, with 1,592 reports in that bracket. The single most reported reaction is off label use with 1,776 submissions, followed by drug ineffective and no adverse event.
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.