Update in Neuroleptic Malignant Syndrome

To the Editor.  —I was interested in the article entitled "The Neuroleptic Malignant Syndrome" by Smego and Durack that was published in the June 1982 Archives (142:1183-1185). The hypothesis of central dopaminergic-receptor blockade is inconsistent with all observed features. There is an early appearance of the muscular syndrome, and the increase of serum creatine kinase levels precedes the rise in temperature. This muscular syndrome is not antagonized by atropinics.Several authors^1-5 have pointed out the similarity between malignant hyperthermia during anesthesia and the neuroleptic malignant syndrome; they have used dantrolene as treatment. This peripheral antispasmodic drug is derived from the hydantoins and leads to normal temperature, as well as normal levels of creatine kinase, within 48 hours. Dantrolene therapy should be administered through a nasogastric tube or preferably by an endovenous route at the initial dose of 1 mg/kg.The purely peripheral action of this drug, which inhibits ionized