Mechanism of action of dantrolene sodium, a peripherally acting muscle relaxant

The mechanism of action of dantrolene sodium, a peripherally acting muscle relaxant, is reviewed. It does not alter action potentials or responses of the contractile proteins to Ca. The amount of Ca acting on the contractile proteins during twitch must, therefore, be reduced, but since Ca uptake by the SR is not altered, Ca release from the SR must be reduced by the drug. Other characteristics of this drug and their clinical implications are discussed.