Dantrolene
Dantrolene is a direct-acting muscle relaxant used to treat spasticity and manage malignant hyperthermia. It works by inhibiting calcium release from the sarcoplasmic reticulum in skeletal muscle cells, reducing muscle contraction. The medication is available in both oral and intravenous formulations for different clinical situations.
A muscle relaxant that directly acts on skeletal muscle to treat spasticity and prevent or treat malignant hyperthermia crises.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- M03CA01
- RxNorm
- 3105
- Generic
- Dantrolene
- Class
- atc-m03
- Brands
- Revonto, Ryanodex, Dantrium
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- solution, capsule, injection
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dantrolene is used to manage chronic spasticity associated with neurological conditions such as cerebral palsy, spinal cord injury, stroke, and multiple sclerosis. It is also used for both the emergency treatment and perioperative prevention of malignant hyperthermia, a potentially life-threatening reaction to certain anesthetic agents.
Dantrolene acts directly on skeletal muscle by blocking the release of calcium from the sarcoplasmic reticulum through ryanodine receptors. This reduces the force of muscle contraction without affecting neuromuscular transmission or nerve conduction.
Dantrolene may cause hepatotoxicity, including hepatitis and liver failure, particularly with prolonged use. Common side effects include drowsiness, dizziness, weakness, and diarrhea. When used for malignant hyperthermia, it should be administered in an acute care setting with appropriate monitoring and support measures.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy