Dantrolene is an FDA approved drug to treat malignant hyperthermia, neuroleptic malignant syndrome and muscle spasm etc., with tolerable side effects and toxicity [28] [29] Clinical use of dantrolene up to now primarily targeted to inhibition of type 1 ryanodine receptors in the skeletal muscles. This evidence concerns the gene RYR1 and Malignant hyperthermia.