Dantrolene
Ryanodex (dantrolene sodium) is a muscle relaxant used to treat malignant hyperthermia, a life-threatening reaction to certain inhaled anesthesia agents and depolarizing muscle relaxants. It is administered in hospital settings, typically during or immediately following surgery, to reverse the hypermetabolic crisis associated with this condition.
Ryanodex is a hospital-administered muscle relaxant used to treat malignant hyperthermia crises triggered by specific anesthesia agents.
Key facts at a glance
- RxNorm
- 1544754
- Generic
- Ryanodex
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- 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.
Ryanodex is indicated for the treatment of malignant hyperthermia, a rare but potentially fatal genetic condition triggered by exposure to volatile anesthetics (such as halothane, sevoflurane, or desflurane) or succinylcholine during surgery. It is also used as a preventive measure in susceptible patients undergoing procedures requiring triggering agents.
Ryanodex contains dantrolene sodium, which works by binding to ryanodine receptors on the sarcoplasmic reticulum in skeletal muscle cells. This action inhibits the release of calcium into the muscle cytoplasm, thereby stopping the uncontrolled muscle contraction and hypermetabolic cascade characteristic of malignant hyperthermia.
Ryanodex is administered intravenously in acute crisis situations and should be given in a hospital setting with appropriate monitoring. Common side effects may include muscle weakness, drowsiness, and respiratory complications. Precipitating agents must be discontinued immediately upon suspicion of malignant hyperthermia. Patients with known susceptibility should inform their healthcare providers prior to any procedure.
Official drug label
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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 9, 2026. · Read our editorial policy