omeprazole Side Effects
Also known as: Prilosec
Analysis of 331,875 adverse event reports submitted to the FDA from 1999 to 2025.
Total Reports
331,875
Death-Related
30,378
9.2% of reports
Hospitalizations
122,601
36.9% 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 30,378 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| DEATH | 9,408 |
| PNEUMONIA | 2,128 |
| ACUTE KIDNEY INJURY | 1,741 |
| DYSPNOEA | 1,556 |
| CHRONIC KIDNEY DISEASE | 1,506 |
| SEPSIS | 1,459 |
| RENAL FAILURE | 1,398 |
| DIARRHOEA | 1,223 |
| RESPIRATORY FAILURE | 1,215 |
| VOMITING | 1,162 |
| NAUSEA | 1,105 |
| CARDIAC ARREST | 1,086 |
| ASTHENIA | 1,075 |
| COMPLETED SUICIDE | 1,037 |
| PYREXIA | 1,027 |
| OFF LABEL USE | 1,008 |
| FATIGUE | 998 |
| ANAEMIA | 907 |
| TOXICITY TO VARIOUS AGENTS | 897 |
| CARDIO-RESPIRATORY ARREST | 834 |
Reactions in Hospitalization Reports
Top reactions in 122,601 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| DYSPNOEA | 8,160 |
| DIARRHOEA | 7,946 |
| PNEUMONIA | 7,846 |
| NAUSEA | 7,140 |
| VOMITING | 7,018 |
| FALL | 6,639 |
| FATIGUE | 6,112 |
| PYREXIA | 5,887 |
| ASTHENIA | 5,276 |
| PAIN | 5,192 |
| ACUTE KIDNEY INJURY | 5,092 |
| MALAISE | 4,753 |
| DIZZINESS | 4,627 |
| DRUG INTERACTION | 4,439 |
| ANAEMIA | 4,293 |
| HYPOTENSION | 4,245 |
| ABDOMINAL PAIN | 4,227 |
| OFF LABEL USE | 4,210 |
| HEADACHE | 4,186 |
| URINARY TRACT INFECTION | 3,748 |
Nearby — Related Medications
What the FAERS Data Reveals About omeprazole Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 331,875 voluntary reports linked to omeprazole and its brand equivalents (Prilosec), spanning 1999 through 2025. Of those, 30,378 (9.2%) listed death as an outcome and 122,601 (36.9%) 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, 59% were female and 41% male; age distribution skews toward 45-64, with 80,287 reports in that bracket. The single most reported reaction is fatigue with 19,901 submissions, followed by nausea and diarrhoea.
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.