FDA Approves Ryanodex (Dantrolene) for Treatment of Malignant Hyperthermia
New antidote allows quicker response
The FDA has approved Ryanodex (dantrolene sodium) for injectable suspension for the treatment of malignant hyperthermia (MH), along with the appropriate supportive measures.
MH is an inherited and potentially fatal disorder triggered by certain anesthesia agents in genetically susceptible individuals.
The FDA had designated Ryanodex as an “orphan drug” in August 2013 and had granted “priority review” status in March 2014. The product will be available through national and regional wholesalers in August.
According to the manufacturer (Eagle Pharmaceuticals), Ryanodex allows anesthesiologists to deliver a therapeutic dose of dantrolene sodium — the only antidote for MH — in a more expedient manner than is currently possible with other intravenous (IV) dantrolene products.
Ryanodex provides a therapeutic loading dose of dantrolene sodium in a single vial. Dantrolene 250 mg is mixed with 5 mL of sterile water and administered to the patient in less than 1 minute. Other dantrolene sodium formulations require multiple 20-mg vials reconstituted in large volumes of sterile water — a process that can take 15 to 20 minutes to mix, reconstitute, and administer.
Ryanodex should be administered by continuous rapid IV push, beginning with a loading dose of 2.5 mg/kg and continuing until symptoms subside.
MH is a condition that can be triggered when genetically susceptible individuals come in contact with certain inhaled (volatile) anesthetics or the muscle relaxant succinylcholine. These patients can experience tachycardia, elevated blood pressure, raised carbon dioxide levels, and a very high body temperature. If not treated immediately, the hypermetabolic episode can be fatal.
Source: Eagle Pharmaceuticals; July 23, 2014.