A Pilot Tolerability and Efficacy Trial of Sodium Oxybate in Ethanol-responsive Movement Disorders

Sodium oxybate is currently approved in the United States exclusively for the treatment of cataplexy in narcoleptic patients. In a prior article published in this journal, we reported a patient with severe posthypoxic myoclonus whose myoclonus improved with ethanol and also with treatment with sodium oxybate. We extend this preliminary observation to five other patients with ethanol-responsive movement disorders in an open-label, dose-titration, add-on, 8-week trial. All five patients (one with severe alcohol-responsive posthypoxic myoclonus, two with epsilon-sarcoglycan-linked myoclonus-dystonia, and two with essential tremor) experienced improvement from baseline of 50% or greater as measured by blinded videotape review. Tolerability was satisfactory, with dose-dependent sedation as the most common side effect. Further studies of this drug in hyperkinetic movement disorders are warranted.