Also Known As: Dantrolene , Dantrium, Dantrolene
Dantrolene sodium is a muscle relaxant that acts by abolishing excitation-contraction coupling in muscle cells, probably by action on the ryanodine receptor. It is the only specific and effective treatment for malignant hyperthermia, a rare, life-threatening disorder triggered by general anesthesia. It is also used in the management of neuroleptic malignant syndrome, muscle spasticity (e.g. after strokes, in paraplegia, cerebral palsy, or patients with multiple sclerosis), 3,4-methylenedioxymethamphetamine ("ecstasy") intoxication, serotonin syndrome, and 2,4-dinitrophenol poisoning. It is marketed by JHP Pharmaceuticals LLC as Dantrium (in North America) and Dantrolen (Europe).
Dantrolene was first described in the scientific literature in 1967, as one of several hydantoin derivatives proposed as a new class of muscle relaxant. Dantrolene underwent extensive further development, and its action on skeletal muscle was described in detail in 1973.
Dantrolene was widely used in the management of spasticity before its efficacy in treating malignant hyperthermia was discovered by South African anesthesiologist Gaisford Harrison and reported in a landmark 1975 article published in the British Journal of Anaesthesia. Harrison experimentally induced malignant hyperthermia with halothane anesthesia in genetically susceptible pigs, and obtained a 87.5% survival rate, where seven of his eight experiments survived after intravenous administration of dantrolene; only one animal died during the course of the study. The efficacy of dantrolene in humans was later confirmed in a large, multicenter study published in 1982. Before dantrolene, the only available treatment for malignant hyperthermia was procaine, which was associated with a 60% mortality rate in animal models.