dantrolene Side Effects
Also known as: Dantrium
Analysis of 580 adverse event reports submitted to the FDA from 2004 to 2025.
Total Reports
580
Death-Related
71
12.2% of reports
Hospitalizations
288
49.7% 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 71 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| NEUROLEPTIC MALIGNANT SYNDROME | 21 |
| DRUG INEFFECTIVE | 20 |
| DEATH | 15 |
| HAEMODYNAMIC INSTABILITY | 9 |
| CARDIAC ARREST | 8 |
| HYPERKALAEMIA | 8 |
| HYPERTHERMIA MALIGNANT | 7 |
| FATIGUE | 6 |
| GLOMERULAR FILTRATION RATE ABNORMAL | 6 |
| HYPERTENSION | 6 |
| HYPERTHERMIA | 6 |
| LABILE BLOOD PRESSURE | 6 |
| OFF LABEL USE | 6 |
| PYREXIA | 6 |
| RHABDOMYOLYSIS | 6 |
| TACHYCARDIA | 6 |
| DRUG INTERACTION | 5 |
| MULTIPLE ORGAN DYSFUNCTION SYNDROME | 5 |
| RENAL FAILURE | 5 |
| RESPIRATORY FAILURE | 5 |
Reactions in Hospitalization Reports
Top reactions in 288 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| NEUROLEPTIC MALIGNANT SYNDROME | 67 |
| DRUG INEFFECTIVE | 55 |
| OFF LABEL USE | 24 |
| PYREXIA | 24 |
| HYPERTHERMIA | 23 |
| RHABDOMYOLYSIS | 21 |
| MUSCLE RIGIDITY | 20 |
| TACHYCARDIA | 20 |
| TREMOR | 19 |
| HYPERTENSION | 18 |
| TOXICITY TO VARIOUS AGENTS | 18 |
| DRUG INTERACTION | 16 |
| AGITATION | 14 |
| DRUG INEFFECTIVE FOR UNAPPROVED INDICATION | 14 |
| FALL | 14 |
| FATIGUE | 14 |
| PNEUMONIA | 14 |
| HYPOTENSION | 13 |
| URINARY TRACT INFECTION | 13 |
| ASTHENIA | 11 |
Nearby — Related Medications
What the FAERS Data Reveals About dantrolene Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 580 voluntary reports linked to dantrolene and its brand equivalents (Dantrium), spanning 2004 through 2025. Of those, 71 (12.2%) listed death as an outcome and 288 (49.7%) 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, 52% were female and 48% male; age distribution skews toward 18-44, with 150 reports in that bracket. The single most reported reaction is drug ineffective with 94 submissions, followed by neuroleptic malignant syndrome 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.