clobazam Side Effects
Also known as: Onfi, Sympazan
Analysis of 23,107 adverse event reports submitted to the FDA from 2002 to 2025.
Total Reports
23,107
Death-Related
1,511
6.5% of reports
Hospitalizations
7,829
33.9% 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 1,511 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| DEATH | 439 |
| TOXICITY TO VARIOUS AGENTS | 147 |
| OFF LABEL USE | 137 |
| DRUG INEFFECTIVE | 115 |
| CARDIAC ARREST | 107 |
| SEIZURE | 98 |
| RESPIRATORY FAILURE | 87 |
| PNEUMONIA | 83 |
| STATUS EPILEPTICUS | 79 |
| COMPLETED SUICIDE | 75 |
| METABOLIC ACIDOSIS | 75 |
| SOMNOLENCE | 71 |
| SUDDEN UNEXPLAINED DEATH IN EPILEPSY | 69 |
| ARRHYTHMIA | 61 |
| OVERDOSE | 57 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 53 |
| SEPSIS | 53 |
| MULTIPLE-DRUG RESISTANCE | 52 |
| COMA | 51 |
| RESPIRATORY DISTRESS | 51 |
Reactions in Hospitalization Reports
Top reactions in 7,829 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| SEIZURE | 1,647 |
| DRUG INEFFECTIVE | 965 |
| OFF LABEL USE | 864 |
| SOMNOLENCE | 600 |
| PNEUMONIA | 517 |
| DRUG INTERACTION | 495 |
| STATUS EPILEPTICUS | 398 |
| HOSPITALISATION | 352 |
| PYREXIA | 349 |
| EPILEPSY | 337 |
| FALL | 310 |
| VOMITING | 305 |
| TOXICITY TO VARIOUS AGENTS | 287 |
| CONDITION AGGRAVATED | 285 |
| PRODUCT USE IN UNAPPROVED INDICATION | 261 |
| FATIGUE | 250 |
| PRODUCT USE ISSUE | 247 |
| GENERALISED TONIC-CLONIC SEIZURE | 232 |
| DECREASED APPETITE | 201 |
| DIARRHOEA | 198 |
Nearby — Related Medications
What the FAERS Data Reveals About clobazam Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 23,107 voluntary reports linked to clobazam and its brand equivalents (Onfi, Sympazan), spanning 2002 through 2025. Of those, 1,511 (6.5%) listed death as an outcome and 7,829 (33.9%) 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, 51% were female and 48% male; age distribution skews toward 0-17, with 5,637 reports in that bracket. The single most reported reaction is seizure with 4,619 submissions, followed by drug ineffective and off label use.
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.