Gamma-hydroxybutyrate in experimental myoclonus.

In Swiss mice, muscimol (3 mg per kilogram, intraperitoneally) caused myoclonic jerks of the hindquarters. These jerks were strong, repetitive, more or less regular, and of high frequency (peak response, 76 per minute). Pretreatment with sodium gamma-hydroxybutyrate (50 to 200 mg per kilogram) caused a dose-dependent blockade of these jerks. This drug also nullified an already developed muscimol response. All of the drugs currently being used in the management of postanoxic action myoclonus (Lance-Adams syndrome) block this response of muscimol. Gamma-hydroxybutyrate may be of value in the management of Lance-Adams syndrome and other forms of myoclonus.