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Dantrolene

Dantrolene is a skeletal muscle relaxant used to treat spasticity from neurological conditions and to manage or prevent malignant hyperthermia, a life-threatening reaction to certain anesthetics.

Brand names DantriumRevontoRyanodexRYANODEX dantrolene sodium
Drug class Skeletal Muscle Relaxant
Rx Forms 2
Dr. Brian Staiger, PharmD, BCPS
Reviewed by Last reviewed Jul 10, 2026 Content updated Oct 2, 2026
🧬 Where this information comes from Click to expand

The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 16 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →

✓No current FDA shortage listed · checked Oct 5, 2026
Dantrolene at a glance The quick version — the full detail is in the Patient Information Guide below.
Dr. Brian Staiger, PharmD, BCPS
The Pharmacist’s Take By · Clinical pharmacist · Written

Dantrolene, on the market since about 1974 and available as a generic, relaxes muscle by blocking the calcium release that triggers contraction. By mouth it is usually a second choice for spasticity (stiff, tight muscles) after stroke, spinal cord injury or multiple sclerosis, and by IV it is the rescue drug for malignant hyperthermia, a life-threatening anesthesia reaction. It often causes drowsiness, dizziness and muscle weakness, sometimes felt as a weaker grip. Its boxed warning is liver damage, which can be fatal and is likelier at higher doses, in women and after age 35, so keep every liver blood test and report yellowing skin or eyes or dark urine promptly.

Clinical pearls

  • If your spasticity is not clearly better within 45 days, the label says to stop the drug.
  • Liver trouble most often appears between 3 and 12 months of treatment, so do not skip those blood draws.
  • Tell your prescriber if you use estrogen therapy, since together with dantrolene it may raise liver risk, especially over 35.
  • Sleep aids, anxiety medicines and other sedatives add to its drowsiness, so hold off driving until you know how it affects you.
How we write & review this content — our editorial policy →
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾

Dantrolene can cause serious and potentially fatal liver damage. This risk is higher with higher doses, in women, in people over 35 years old, in elderly patients, and in those taking other medications at the same time. Liver damage has been reported both with and without obvious symptoms, and most often appears between 3 and 12 months of therapy. Your liver function must be checked regularly with blood tests while you are on this drug. If your liver tests become abnormal, the drug should generally be stopped. If you develop yellowing of the skin or eyes, dark urine, persistent nausea, or right-sided stomach pain, contact your doctor immediately. Dantrolene should only be used for the conditions it is approved for, at the lowest effective dose, and should be discontinued if no benefit is seen within 45 days.

Read the full warning on DailyMed →
How you get itPrescription only
Comes asCapsule, Injection
Earliest FDA record1974
Companies listing it with the FDA14
FDA label last updatedDec 27, 2019
FDA’s strongest warning (boxed)Yes, read the warning

Patient information guide A plain-language walkthrough of Dantrolene, written from its FDA label.

What Dantrolene is used for

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Dantrolene is a skeletal muscle relaxant approved across several products and forms for two main categories of use:

  • Spasticity from neurological conditions (oral capsules only): Dantrium and Dantrolene Sodium capsules are used to treat muscle stiffness, spasms, and clonus caused by upper motor neuron disorders — including spinal cord injury, stroke, cerebral palsy, and multiple sclerosis. The goal is to reduce spasticity enough to improve daily function or reduce the need for intensive nursing care. They are not approved for muscle spasm caused by rheumatic disorders like arthritis.
  • Malignant hyperthermia — treatment (IV forms): Dantrium Intravenous, Revonto, Ryanodex, and Dantrolene injection are indicated to treat an active malignant hyperthermia crisis — a life-threatening emergency of uncontrolled skeletal muscle overactivity triggered by certain anesthetics.
  • Malignant hyperthermia — prevention (IV forms and oral capsules): IV forms (Dantrium Intravenous, Revonto, Ryanodex, Dantrolene) and oral capsules (Dantrium, Dantrolene Sodium) can be given before surgery to help prevent malignant hyperthermia in patients known to be at risk.
  • Post-crisis prevention (oral capsules): Dantrium and Dantrolene Sodium capsules are used after a malignant hyperthermia episode to reduce the risk of it happening again.

How Dantrolene works

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Dantrolene works directly inside muscle cells, not at the nerve-muscle junction. It blocks the release of calcium from a storage compartment inside the cell called the sarcoplasmic reticulum. Since calcium is the trigger that makes muscles contract, reducing its release causes the muscle to relax. In malignant hyperthermia, a triggering anesthetic causes calcium to flood the muscle cell, setting off a dangerous chain reaction of overheating and cellular breakdown. By restoring normal calcium levels inside the muscle, dantrolene can reverse or reduce that crisis.

Dantrolene dosage

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How dantrolene is taken depends entirely on which product is prescribed and why it is being used.

  • Oral capsules (Dantrium, Dantrolene Sodium) for spasticity: Taken by mouth multiple times per day. The dose starts low and is increased gradually over weeks — your prescriber will set the schedule. If no benefit is seen after 45 days, it should be stopped.
  • Oral capsules for malignant hyperthermia prevention: Taken before (and sometimes after) surgery; your surgical team will guide the timing and schedule.
  • IV forms for malignant hyperthermia crisis: Given by a healthcare provider as a rapid push into a vein as soon as a crisis is recognized, and continued until symptoms stop.
  • IV forms for prevention before surgery: Infused slowly before anesthesia under medical supervision — for example, Ryanodex is given starting about 75 minutes before surgery.

Always follow the instructions from your prescriber or healthcare team exactly. Never adjust the dose on your own.

Dosing details from the FDA-approved label

From the Dantrolene prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.

  • Malignant hyperthermia crisis (Revonto/Dantrium Intravenous)
    • Continuous rapid intravenous push beginning at a minimum dose of 1 mg/kg, continuing until symptoms subside
    • If physiologic and metabolic abnormalities reappear, the regimen may be repeated
    • Maximum: maximum cumulative dose of 10 mg/kg
    • Discontinue all anesthetic agents and give 100% oxygen; effective dose depends on individual susceptibility, exposure to the triggering agent, and time elapsed before treatment
  • Pediatric patients (malignant hyperthermia crisis)
    • The dose for pediatric patients is the same as for adults
  • Preoperative prophylaxis in malignant hyperthermia susceptible patients (intravenous)
    • 2.5 mg/kg, starting approximately 1.25 hours before anticipated anesthesia and infused over approximately 1 hour
    • Additional doses during anesthesia and surgery must be individualized
  • Preoperative prophylaxis in malignant hyperthermia susceptible patients (oral dantrolene sodium capsules)
    • 4 to 8 mg/kg/day in three or four divided doses for 1 or 2 days prior to surgery, with the last dose given with a minimum of water approximately 3 to 4 hours before scheduled surgery
    • Adjust within the recommended range to avoid incapacitation or excessive gastrointestinal irritation
  • Post crisis follow-up (oral dantrolene sodium capsules)
    • 4 to 8 mg/kg/day in four divided doses for 1 to 3 days following a malignant hyperthermia crisis
  • Post crisis follow-up (intravenous, when oral administration is not practical)
    • Individualized, starting with 1 mg/kg or more as the clinical situation dictates
  • Treatment of malignant hyperthermia (Ryanodex)
    • Intravenous push at a minimum of 1 mg/kg
    • If signs continue, additional intravenous boluses
    • Maximum: maximum cumulative dosage of 10 mg/kg
    • Institute supportive measures
Read the label’s full dosing text

DOSAGE AND ADMINISTRATION For Use in Chronic Spasticity Prior to the administration of dantrolene sodium capsules, consideration should be given to the potential response to treatment. A decrease in spasticity sufficient to allow a daily function not otherwise attainable should be the therapeutic goal of treatment with dantrolene sodium capsules. Refer to INDICATIONS AND USAGE section for description of response to be anticipated. It is important to establish a therapeutic goal (regain and maintain a specific function such as therapeutic exercise program, utilization of braces, transfer maneuvers, etc.) before beginning dantrolene sodium capsule therapy. Dosage should be increased until the maximum performance compatible with the dysfunction due to underlying disease is achieved. No further increase in dosage is then indicated. Usual Dosage It is important that the dosage be titrated and individualized for maximum effect. The lowest dose compatible with optimal response is recommended. In view of the potential for liver damage in long-term dantrolene sodium capsule use, therapy should be stopped if benefits are not evident within 45 days. Adults The following gradual titration schedule is suggested. Some patients will not respond until higher daily dosage is achieved. Each dosage level should be maintained for seven days to determine the patient's response. If no further benefit is observed at the next higher dose, dosage should be decreased to the previous lower dose. 25 mg once daily for seven days, then 25 mg t.i.d. for seven days 50 mg t.i.d. for seven days 100 mg t.i.d. Therapy with a dose four times daily may be necessary for some individuals. Doses higher than 100 mg four times daily should not be used (see Box Warning ). Pediatric Patients The following gradual titration schedule is suggested. Some patients will not respond until higher daily dosage is achieved. Each dosage level should be maintained for seven days to determine the patient's response. If no further benefit is observed at the next higher dose, dosage should be decreased to the previous lower dose. 0.5 mg/kg once daily for seven days, then 0.5 mg/kg t.i.d. for seven days 1 mg/kg t.i.d. for seven days 2 mg/kg t.i.d. Therapy with a dose four times daily may be necessary for some individuals. Doses higher than 100 mg four times daily should not be used (see Box Warning ).

Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →

Dantrolene side effects

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Side effects vary by form and dose, but the most common ones include:

Common side effects

  • Muscle weakness or loss of grip strength
  • Drowsiness or sleepiness
  • Dizziness
  • Nausea
  • Flushing
  • Difficulty swallowing (dysphagia)
  • Injection site pain, redness, or swelling (IV forms)
  • Nausea and vomiting
  • Difficulty swallowing or voice changes
  • Blurred vision

When to get medical help

  • Call your doctor right away if you notice yellowing of the skin or eyes, dark urine, or severe stomach pain — these can be signs of liver damage
  • Seek emergency help if you have difficulty breathing or severe muscle weakness
  • Tell your doctor immediately if you have trouble swallowing or feel like you are choking after a dose
  • Do not drive or operate machinery for at least 48 hours after receiving an IV dose — serious drowsiness and dizziness can persist
  • Get medical help for signs of a serious allergic reaction: hives, rash, or swelling

More serious reactions include liver damage (watch for yellowing of the skin, dark urine, or persistent stomach pain), breathing difficulty, severe muscle weakness, pulmonary edema (fluid in the lungs), and serious allergic reactions including anaphylaxis. Seek medical help right away if any of these occur.

Dantrolene warnings and precautions

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  • Liver damage (hepatotoxicity): This is the most serious risk and can be fatal. It is more likely at higher doses, in women, in people over 35, in older adults, and in those on multiple medications. Liver function tests must be checked regularly. If no benefit appears within 45 days of oral therapy, the drug should be stopped.
  • Muscle weakness and breathing problems: IV dantrolene can cause significant muscle weakness, including in the respiratory muscles. Patients need assisted ambulation and monitoring of their breathing until strength returns.
  • Drowsiness lasting up to 48 hours: After IV administration, patients must not drive or operate dangerous equipment for 48 hours. Sedatives given at the same time increase this risk.
  • Tissue damage from IV leakage: The IV solution has a high pH. If it leaks outside the vein, it can damage surrounding tissue. Healthcare providers take special precautions during administration.
  • Pulmonary edema (fluid in the lungs): Has been reported during IV treatment for malignant hyperthermia.

Dantrolene interactions

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Dantrolene can interact with several drugs — make sure your care team knows everything you take:

  • Sedatives and tranquilizers (CNS depressants): Increase drowsiness and dizziness when combined with dantrolene.
  • Calcium channel blockers (e.g., verapamil): Should not be used together during malignant hyperthermia management — the combination has caused dangerous heart rhythm problems and cardiovascular collapse in animal studies.
  • Estrogen therapy: Combined use has been linked to increased liver toxicity, particularly in women over 35.
  • Vecuronium (a neuromuscular blocking agent): Dantrolene can intensify its muscle-relaxing effects.
  • Warfarin and clofibrate: May reduce how much dantrolene binds to blood proteins, potentially affecting drug levels.
  • Tolbutamide: May increase dantrolene's protein binding.

Interactions listed in the FDA-approved label

From the Dantrolene prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.

  • CNS depressants such as sedatives and tranquilizing agents: Concomitant administration may result in further drowsiness.
  • Estrogen therapy: A definite interaction has not been established, but hepatotoxicity has occurred more often in women over 35 years of age receiving concomitant estrogen therapy. Caution should be observed if the two drugs are given concomitantly.
  • Verapamil: Cardiovascular collapse in patients treated simultaneously is rare; in swine, intravenous dantrolene with verapamil resulted in ventricular fibrillation and cardiovascular collapse with marked hyperkalemia. Combination with calcium channel blockers is not recommended during the management of malignant hyperthermia.
  • Calcium channel blockers: Findings in swine with verapamil raise concern about cardiovascular collapse with combined use. Combination is not recommended during the management of malignant hyperthermia until relevance to humans is established.
  • Vecuronium: Dantrolene sodium may potentiate vecuronium-induced neuromuscular block.
Read the label’s full interactions text

Drug Interactions Drowsiness may occur with dantrolene sodium therapy, and the concomitant administration of CNS depressants such as sedatives and tranquilizing agents may result in further drowsiness. While a definite drug interaction with estrogen therapy has not yet been established, caution should be observed if the two drugs are to be given concomitantly. Hepatotoxicity has occurred more often in women over 35 years of age receiving concomitant estrogen therapy. 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. Until the relevance of these findings to humans is established, the combination of dantrolene sodium and calcium channel blockers is not recommended during the management of malignant hyperthermia. Administration of dantrolene sodium may potentiate vecuronium-induced neuromuscular block.

Read the full Drug Interactions section on DailyMed →

Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.

🌿77 supplements and herbs with documented Dantrolene interactions, ranked by severity Check Dantrolene against a supplement or herb →

Before taking Dantrolene

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  • Do not take oral dantrolene capsules if you have active liver disease such as hepatitis or cirrhosis.
  • Do not use oral dantrolene capsules if your muscle stiffness (spasticity) is what allows you to stand, walk, or stay balanced — relieving it could make function worse.
  • Women and people over 35 years old are at higher risk for serious liver damage; discuss this carefully with your prescriber.
  • Tell your prescriber about all your medications, especially sedatives, estrogen, verapamil, or other calcium channel blockers.
  • If you are pregnant: dantrolene crosses the placenta. For a malignant hyperthermia emergency, treatment should not be withheld because of pregnancy. For non-emergency oral use, discuss the risks with your prescriber.
  • Do not breastfeed during IV dantrolene treatment or for 3 days after — the drug passes into breast milk and may harm a nursing infant.
  • The long-term safety of oral dantrolene in children under 5 has not been established.
  • Older adults should be monitored especially closely, as they have a higher reported rate of serious and fatal liver complications.

Dantrolene overdose

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Too much dantrolene can cause symptoms including muscle weakness, altered consciousness (such as lethargy or coma), vomiting, diarrhea, and crystalluria (crystals in the urine). If an overdose is suspected, general supportive care is given, including IV fluids to protect the kidneys, airway maintenance, and heart monitoring. The usefulness of dialysis for removing dantrolene is not established.

What Dantrolene does in the body

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When dantrolene is given intravenously to healthy volunteers, it produces measurable loss of grip strength and leg weakness, as well as subjective feelings of central nervous system (CNS) effects. These effects reflect the drug doing exactly what it is designed to do — reducing the force of skeletal muscle contractions — but also confirm that muscle weakness is a real and expected consequence of treatment.

How your body processes Dantrolene

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After IV administration of Ryanodex, peak drug levels in the blood are reached within about 1 minute. Dantrolene has a half-life (the time for the body to clear half the drug) of roughly 8.5 to 11.4 hours. It binds significantly to albumin (a blood protein), and slightly more of the drug is carried in red blood cells than in plasma. Dantrolene is broken down by the liver into several metabolites, including 5-hydroxydantrolene; liver-enzyme-inducing drugs may speed up this process. The drug and its breakdown products are found in both blood and urine.

How to store Dantrolene

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Store at 20° to 25°C (68° to 77°F) . Protect from moisture and humidity. Dispense in a tightly-closed, light-resistant container (USP).

Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →

77

Supplements & herbs that interact with Dantrolene

77 supplements and herbal products have documented interactions with Dantrolene in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.

Severity mix
  • Major · 5
  • Moderate · 62
  • Minor · 10
ACTIVATED CHARCOAL Major BEER Major PROCAINE Major SIBERIAN COCKLEBUR Major WINE Major ALFALFA Moderate ANGELICA ARCHANGELICA Moderate ARRACH Moderate +69 more
Every supplement checked against Dantrolene — ranked by severity The full interaction hub: 5 major · 62 moderate · 10 minor · every one linked to its full report. Check Dantrolene against your exact supplements

Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.

Dantrolene: pharmacist answers to common questions

Quick, plain-English answers to the questions patients ask most about Dantrolene — the kind of thing our pharmacy team would talk through with you at the counter.

What is dantrolene actually used for?

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Dantrolene is used for two main things. If you're taking the capsules (Dantrium or Dantrolene Sodium), it's most likely to help control muscle stiffness and spasms caused by conditions like spinal cord injury, stroke, cerebral palsy, or multiple sclerosis. The IV forms — given in a hospital — are used to treat or prevent malignant hyperthermia, which is a dangerous, life-threatening muscle reaction that can happen with certain anesthetics during surgery.

What are the most important side effects I should watch for?

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The most serious risk is liver damage. Watch for yellowing of your skin or the whites of your eyes, very dark urine, persistent nausea, or pain in the upper right side of your abdomen, and contact your doctor immediately if any of these appear. Day-to-day, you may notice muscle weakness, drowsiness, or dizziness — especially early on. These are expected to some degree, but if weakness is severe or you have trouble breathing or swallowing, get medical help right away.

Why does my doctor keep checking my liver while I'm on this?

▾
Dantrolene can cause liver damage — and this is the number one safety concern with long-term use. Regular blood tests (liver function tests) are the only way to catch a problem early, before it becomes serious. Your risk is higher if you're a woman, over 35, on other medications, or taking higher doses. If the tests show your liver is being affected, your doctor will likely stop the drug. Please don't skip those monitoring appointments — they matter.

Can I drive or go about my normal day while taking dantrolene?

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If you're on the oral capsules, be careful — drowsiness and dizziness are common, especially when you first start or after a dose increase. Avoid driving or anything that requires full alertness until you know how the drug affects you. If you've been given an IV dose of dantrolene (for example, Ryanodex), you must not drive or operate machinery for at least 48 hours afterward, because significant drowsiness and muscle weakness can persist.

Is dantrolene safe to take if I'm pregnant or breastfeeding?

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This depends on the situation. In a life-threatening malignant hyperthermia emergency during pregnancy, treatment should not be withheld — the risk of not treating is greater than the drug's risks. For non-emergency oral use, dantrolene should only be taken during pregnancy if clearly needed, and you should discuss the risks fully with your prescriber. For breastfeeding: the drug passes into breast milk, so you should not breastfeed while taking dantrolene or for at least 3 days after an IV dose. Pump and discard your milk during that period.

How will I know if dantrolene is actually working for my muscle spasticity?

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Your prescriber will watch for a meaningful reduction in painful muscle stiffness, spasms, or clonus (rhythmic, involuntary muscle jerking), and whether you're able to do daily activities that were too difficult before. If you don't notice any improvement after about 45 days, your prescriber should stop the medication — there's no benefit in continuing if it isn't helping, especially given the liver risk. Sometimes the improvement is subtle, so it helps to keep track of how you're functioning day-to-day and share that with your care team.

Is Dantrolene available over the counter?

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No. Dantrolene is a prescription medicine: every Dantrolene product listed with the FDA is prescription only, so it is not sold over the counter. Your prescriber decides whether it is appropriate for you, and your pharmacist dispenses it.

When was Dantrolene first available?

▾
The earliest FDA record we hold for Dantrolene is from 1974: its first approval in Drugs@FDA or its earliest product listing in the NDC Directory, whichever is older. Many older medicines were in use before their first formal FDA approval, so this is the earliest date on record, not necessarily when Dantrolene was first used.

Who makes Dantrolene?

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14 companies currently list Dantrolene products in the FDA's NDC Directory, including Bryant Ranch Prepack, Endo USA, Inc., Amneal Pharmaceuticals of New York LLC. That count includes repackagers and distributors as well as manufacturers (companies that sell only the raw ingredient are not counted), so fewer companies actually make it; the label on your bottle names the one that supplied yours.

Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →

More about Dantrolene on HelloPharmacist

📊Dantrolene supplement interactions77 checked — ranked by severity 🌿Drug & Supplement CheckerDantrolene vs. vitamins & herbs 💬Ask a PharmacistFree answer, usually < 24h 🔎NDC & pricing lookupFind Dantrolene NDCs & costs 🅰️Browse Drugs A–ZLook up any medication
Detailed data & references for Dantrolene Forms & strengths, pricing, billing codes, manufacturers, safety reports and sourcing — the data behind the page. Most people can stop here. Each section below opens on a tap.

Dantrolene forms and strengths (how it comes)

Dantrolene is available in 2 forms. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.

Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Dantrolene inactive ingredients by manufacturer.

Capsule

By mouth
Brands Dantrium
How this form is used
What it may be used for
  • Dantrium and Dantrolene Sodium capsules treat spasticity caused by spinal cord injury, stroke, cerebral palsy, or multiple sclerosis
  • Dantrium and Dantrolene Sodium capsules are used before surgery to help prevent malignant hyperthermia in susceptible patients
  • Dantrium and Dantrolene Sodium capsules are used after a malignant hyperthermia crisis to help prevent it from coming back
  • Not for muscle spasm caused by rheumatic or arthritic conditions
Important instructions
  • Dantrium and Dantrolene Sodium capsules are taken by mouth, typically multiple times per day, with dosing increased gradually over weeks under prescriber guidance
  • If no meaningful improvement in spasticity is seen after 45 days, Dantrium and Dantrolene Sodium therapy should be stopped
  • Use the lowest dose that provides benefit; your prescriber will adjust your dose individually
  • Do not stop taking Dantrium or Dantrolene Sodium capsules without talking to your prescriber first
Available strengths 3 strengths
25 mg 50 mg 100 mg
55 FDA-listed product records ⓘ

Injection

By injection · Into a vein
Brands Dantrium Revonto Ryanodex
How this form is used
What it may be used for
  • Dantrium Intravenous, Revonto, Ryanodex, and Dantrolene injection are used to treat an active malignant hyperthermia crisis in the hospital
  • Dantrium Intravenous, Revonto, Ryanodex, and Dantrolene injection may be given before (and sometimes after) surgery to prevent malignant hyperthermia in high-risk patients
Important instructions
  • Dantrium Intravenous, Revonto, and Dantrolene injection are given by continuous rapid IV push by a healthcare provider as soon as a malignant hyperthermia reaction is recognized
  • Ryanodex is given by IV push; for prevention before surgery, it is infused over at least 1 minute starting approximately 75 minutes before anesthesia
  • All IV forms are administered only by trained healthcare providers in a medical setting — never self-administered
  • Care is taken to avoid the IV solution leaking outside the vein, as it can cause tissue damage
Available strengths 3 strengths
20 mg 20 mg/60 mL 250 mg/5 mL
10 FDA-listed product records ⓘ

Dantrolene on the U.S. market: products, makers and brands

How Dantrolene appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.

14 companies list 27 Dantrolene product records with the FDA, mostly as capsule, injection; the earliest marketing or approval year on record is 1974. Brand names on the directory include Dantrium, Revonto, Ryanodex and 1 more; the rest are generics.

2
Dose forms ⓘ
14
Labelers (makers, repackagers, distributors)
6
Brand names
27
FDA-listed product records ⓘ
1974
Earliest FDA record ⓘ

FDA-listed product records by dose form (tablet variants merged) — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

Also listed with the FDA, not a patient dose form: Powder (6) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.

Bryant Ranch Prepack22%
Endo USA, Inc.15%
Amneal Pharmaceuticals of New York LLC11%
Elite Laboratories, Inc.11%
Remedyrepack Inc.7%
American Health Packaging4%
Other makers30%

Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

How widely Dantrolene is used (Medicaid data)

A general measure of how commonly Dantrolene is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.

Think of this as a proxy for how widely Dantrolene is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.

18,142
Medicaid prescriptions filled (Q1–Q4 2025)
$1.1M gross Medicaid reimbursement (before mandatory rebates — net cost is lower)

How commonly is Dantrolene prescribed? Of the 1,601 medications we measure, Dantrolene ranks #811 by Medicaid prescriptions — more than 49% of them.

Where Dantrolene ranks among the drugs we measure · Q1–Q4 2025 · neighbors ±5
Total prescriptions — #811 of 1,601
#806 Methylnaltrexone 18,616 Rx #807 Tralokinumab-ldrm inje... 18,603 Rx #808 Insulin Glulisine (rDN... 18,473 Rx #809 Baloxavir Marboxil 18,342 Rx #810 Exenatide Injection 18,238 Rx #811 Dantrolene 18,142 Rx #812 Candesartan 18,097 Rx #813 Levomilnacipran 17,968 Rx #814 Macitentan 17,860 Rx #815 Ciprofloxacin and Hydr... 17,777 Rx #816 Ciprofloxacin / Hydroc... 17,777 Rx

Utilization by Dantrolene product

Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.

The 25 mg oral capsule is the most-dispensed Dantrolene product — about 55% of these Medicaid prescriptions.

dantrolene sodium 25 MG Oral Capsule Most dispensed

9,952 Medicaid prescriptions (Q1–Q4 2025) 55% of Dantrolene prescriptions shown $517,380 gross reimbursement (before rebates) ≈ $52 per prescription (gross)

Summed across the 2 of 16 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 856656

dantrolene sodium 50 MG Oral Capsule

5,023 Medicaid prescriptions (Q1–Q4 2025) 28% of Dantrolene prescriptions shown $366,835 gross reimbursement (before rebates) ≈ $73 per prescription (gross)

Summed across the 2 of 11 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 856660

dantrolene sodium 100 MG Oral Capsule

3,167 Medicaid prescriptions (Q1–Q4 2025) 17% of Dantrolene prescriptions shown $256,300 gross reimbursement (before rebates) ≈ $81 per prescription (gross)

Summed across the 2 of 12 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 856652

Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.

Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Dantrolene, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 6 of 39 listed Dantrolene NDCs with Medicaid activity.

Compare Dantrolene products

A representative set of FDA-listed product records for Dantrolene — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)

Showing 27 of 27 products — FDA National Drug Code Directory. See every product, package size and price: browse all 27 Dantrolene NDCs →

Dantrolene recall history

A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.

The FDA’s enforcement reports list one Dantrolene recall since July 2021. It is no longer listed as ongoing. A recall names specific lots from one company, so check the lot number on your own bottle rather than assuming every product is affected; your pharmacist can check whether your supply came from an affected lot.

Class II Apr 13, 2022 · Terminated · Mckesson Medical-Surgical Inc. Corporate Office
cGMP deviations: Temperature abuse
  • Revonto (dantrolene sodium for injection), 20 mg/vial, 6-count box, Rx only, MFG: US WorldMeds, Inc., NDC 78670-003-67 Lots: McKesson Medical-Surgical (MMS) is not able to identify the particular lot number received by a particular consignee for the recalled prescription products. Each letter includes the date it was distributed to customers and the dates that i… FDA record D-1081-2022 →

Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.

RxNorm Concept Web — From Ingredient to Every Form and Strength

This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.

Ingredient (IN) Dantrolene RxCUI 3105 3 dose forms · 5 strengths
  1. Dose form (SCDF) Injectable Solution RxCUI 377095 In current FDA listings
    Clinical drug / strength (SCD) sodium 0.333 MG/ML RxCUI 856696
  2. Dose form (SCDF) Injection RxCUI 1791243 In current FDA listings
    Clinical drug / strength (SCD) sodium 250 MG RxCUI 1544753
  3. Dose form (SCDF) Oral Capsule RxCUI 371688 In current FDA listings
    Clinical drug / strength (SCD) sodium 100 MG RxCUI 856652 sodium 25 MG RxCUI 856656 sodium 50 MG RxCUI 856660

Look up RxCUI 3105 in the RxCUI Atlas →

RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.

💵 What Dantrolene costs pharmacies (NADAC benchmark)

The national average invoice price pharmacies pay for the drug itself, from CMS's NADAC survey (data as of Sep 30, 2026). This is a supply-cost benchmark — not a retail price and not what you'd pay at the counter.

FormStrengthPharmacy acquisition benchmark
Capsule · Oral 25 mg $0.409 per capsule NDC details & price history
Capsule · Oral 50 mg $0.554 per capsule NDC details & price history
Capsule · Oral 100 mg $1.01 per capsule NDC details & price history
Why show this? Your out-of-pocket cost depends on insurance, pharmacy markup, and discounts — but the acquisition benchmark tells you whether the medication itself is inexpensive or costly, which strengths cost more per dose, and whether a cash-price quote is in a reasonable range. Each row links to the NDC-level record with its full price history.

Source: CMS National Average Drug Acquisition Cost (NADAC), a survey of retail pharmacy invoice prices. Benchmarks shown are the range across package sizes of a representative product for each form and strength — other manufacturers' products may differ.

Dantrolene brand names

Dantrolene is sold under 4 brand names in the FDA directory — Dantrium, Revonto, Ryanodex, RYANODEX dantrolene sodium. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.

Dantrium Revonto Ryanodex RYANODEX dantrolene sodium

Who makes Dantrolene: manufacturers and labelers

14 companies list Dantrolene products with the FDA. By number of product records, the largest are Bryant Ranch Prepack, Endo USA, Inc., Amneal Pharmaceuticals of New York LLC. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.

Bryant Ranch Prepack 6 Endo USA, Inc. 4 Amneal Pharmaceuticals of New York LLC 3 Elite Laboratories, Inc. 3 Remedyrepack Inc. 2 American Health Packaging 1 AvPAK 1 Cardinal Health 107, LLC 1 Eagle Pharmaceuticals, Inc. 1 Hikma Pharmaceuticals USA Inc. 1 Major Pharmaceuticals 1 Par Health USA, LLC 1 ProPharma Distribution 1 Uswm, Llc 1

Dantrolene drug class (RxNorm)

Dantrolene belongs to the Skeletal Muscle Relaxant class.

Pharmacologic class Skeletal Muscle Relaxant
Drug family (ATC) Dantrolene and derivatives

Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.

Sources for this Dantrolene page

Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.

📄
FDA-filed drug labels (SPL) Uses, dosing, warnings & side effects from SPL records retrieved through openFDA; the linked representative set can be verified on DailyMed. ✓ Linked label effective Dec 27, 2019
🏭
Forms, brands & labelersAggregated from ingredient-matched FDA National Drug Code Directory product records for Dantrolene.
📈
Real-world reportsThe FDA Adverse Event Reporting System (FAERS), served through openFDA.
🚨
Recalls & shortagesopenFDA drug-enforcement reports and the FDA drug-shortage database.
🧾 Clinical label set — FDA-filed SPL labels retained for Dantrolene after exact ingredient or ingredient-combination matching and applicable route/form matching
Clinical labels in scope
16
Finished products in the current FDA directory
27
Companies listing them (makers, repackagers, distributors)
14
FDA labeler codes behind them ⓘ
15
Linked representative label ⓘ
Elite Laboratories, Inc.
Linked label effective
Dec 27, 2019
Composite sections available
20
Linked SPL Set ID
e637fb20-6a17-4522-810a-990bf1409732
Linked SPL Document ID
e3fc6ec6-cdde-456a-81bd-8ebd07065afc
Open the linked representative label on DailyMed ↗

How this page is built

HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Elite Laboratories, Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →