Prescription medication · Direct-Acting Muscle Relaxant
dantrolene
Also sold as Dantrium. Dantrolene treats muscle stiffness and spasms from conditions like spinal cord injury, stroke, cerebral palsy, or multiple sclerosis.
Data updated 2026-05-15
- 580
- FDA reportsRarely reported
- 2
- InteractionsFew interactions
- $0.92
- Generic price (NADAC)
What the data shows
dantrolene (Dantrium) is a prescription Direct-Acting Muscle Relaxant, among the least-reported drugs the FDA tracks (580 FDA reports), with 2 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
dantrolene (Dantrium) is a prescription Direct-Acting Muscle Relaxant. Dantrolene treats muscle stiffness and spasms from conditions like spinal cord injury, stroke, cerebral palsy, or multiple sclerosis.
Dantrolene is a muscle relaxant. It helps to reduce muscle spasms and stiffness caused by certain conditions.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Generic Price
$0.92/unit
Generic Available
Yes (4 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Dantrolene treats muscle stiffness and spasms from conditions like spinal cord injury, stroke, cerebral palsy, or multiple sclerosis.
Common side effects
Drowsiness, Dizziness, Weakness
Key warnings
Dantrolene can potentially damage your liver.
The sections below are summarized in plain English from dantrolene's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Dantrolene works directly on your muscles to relax them. It reduces the amount of calcium released in muscle cells. This helps to decrease muscle contractions and spasms.
Side Effects (from patient reports)
Based on 580 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for dantrolene, by number of reports
- Neuroleptic Malignant Syndrome
Neuroleptic Malignant Syndrome
81 reports
- Pyrexia 30
Pyrexia
30 reports
- Drug Interaction 27
Drug Interaction
27 reports
- Fall 26
Fall
26 reports
- Hyperthermia 26
Hyperthermia
26 reports
- Muscle Rigidity 25
Muscle Rigidity
25 reports
- Rhabdomyolysis 25
Rhabdomyolysis
25 reports
- Drug Ineffective For Unapproved Indication 24
Drug Ineffective For Unapproved Indication
24 reports
- Tachycardia 23
Tachycardia
23 reports
- Urinary Tract Infection 23
Urinary Tract Infection
23 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for dantrolene each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where dantrolene sits
dantrolene has more FDA adverse-event reports than 4% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is dantrolene; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 580 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
580
Reports Mentioning Death
71
12.2% of reports — not proof of cause
Hospitalization Reports
288
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 2 | NEUROLEPTIC MALIGNANT SYNDROME | 81 |
| 4 | PYREXIA | 30 |
| 5 | DRUG INTERACTION | 27 |
| 6 | FALL | 26 |
| 7 | HYPERTHERMIA | 26 |
| 8 | MUSCLE RIGIDITY | 25 |
| 9 | RHABDOMYOLYSIS | 25 |
| 10 | DRUG INEFFECTIVE FOR UNAPPROVED INDICATION | 24 |
| 11 | TACHYCARDIA | 23 |
| 12 | URINARY TRACT INFECTION | 23 |
| 13 | FATIGUE | 22 |
| 14 | HYPERTENSION | 21 |
| 15 | TREMOR | 21 |
| 16 | MUSCLE SPASMS | 20 |
| 17 | PAIN | 19 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Dantrolene can potentially damage your liver. Your doctor should monitor your liver function with blood tests. Tell your doctor if you have any signs of liver problems, such as yellowing of the skin or eyes, dark urine, or abdominal pain. If you don't see any benefit after 45 days, stop taking dantrolene.
Known Drug Interactions
Cardiovascular collapse in patients treated simultaneously with verapamil and Dantrolene Sodium is rare. The combination of therapeutic doses of intravenous Dantrolene Sodium and verapamil in halothane/ α -chloralose anesthetized swine has resulted in ventricular fibrillation and cardiovascular collapse in association with marked hyperkalemia.
Mechanism: Combining these drugs may lead to very high potassium levels, which can cause the heart to stop working correctly.
Concomitant use of carbamazepine with olanzapine, dantrolene, or ibuprofen may increase plasma carbamazepine levels.
Mechanism: Dantrolene can slow down how your body processes carbamazepine, causing the drug to build up in your system.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
Common Questions
Can I drive while taking dantrolene?
How long does it take for dantrolene to start working?
Can I take dantrolene with other medications?
What should I do if I experience severe diarrhea?
Is dantrolene a cure for spasticity?
Can I stop taking dantrolene suddenly?
Does dantrolene interact with alcohol?
What if I am over 65?
Can dantrolene cause me to fall?
Will dantrolene help with muscle spasms from arthritis?
What are the common side effects of dantrolene?
Does dantrolene interact with other medications?
What drug class is dantrolene?
What pregnancy or breastfeeding source fields are listed for dantrolene?
Related Medications in Direct-Acting Muscle Relaxant
Other drugs grouped near dantrolene - same-class peers and common alternatives.
baclofen
Lioresal, Gablofen
Baclofen is a muscle relaxant.
Compare with dantrolene →
botulinum toxin A
Botox
Botox is a drug that blocks nerve signals to muscles.
Compare with dantrolene →
carisoprodol
Soma
Carisoprodol is a muscle relaxant.
Compare with dantrolene →
chlorzoxazone
Parafon Forte
Chlorzoxazone is a muscle relaxant.
Compare with dantrolene →
cyclobenzaprine
Flexeril, Amrix
Cyclobenzaprine is a muscle relaxant.
Compare with dantrolene →
Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for dantrolene: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 580.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 12.24%.
- nortriptyline Δ 0.01 pts · 5,503 reports · Tricyclic Antidepressant (TCA) 12.25%death share
- diclofenac Δ 0.01 pts · 82,165 reports · Nonsteroidal Anti-Inflammatory Drug (NSAID) 12.23%death share
- benzonatate Δ 0.01 pts · 15,513 reports · Antitussive (Non-Narcotic) 12.23%death share
- carvedilol Δ 0.07 pts · 130,791 reports · Beta-Blocker (Alpha/Beta) 12.17%death share
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
FDA bioequivalence and label-record context for narrow therapeutic index medicines
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for dantrolene
The FDA label for dantrolene (sold under brand names such as Dantrium) classifies it as a prescription-only medication in the Direct-Acting Muscle Relaxant class. Dantrolene treats muscle stiffness and spasms from conditions like spinal cord injury, stroke, cerebral palsy, or multiple sclerosis. Official labeling lists 6 commonly reported side effects, including Drowsiness, Dizziness, Weakness.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 580 voluntary reports. The database also lists 2 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS shows a generic unit cost of $0.92.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: December 22, 2024
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages