Abstract: The invention is directed to methods of treating movement disorders by administering an effective amount of the compound of formula (I) to patients in need thereof. More particularly, the invention is directed to a method for treating myoclonus including administering to a patient a compound of formula (I), wherein the myoclonus is not alcohol responsive essential myoclonus with dystonia. In some embodiments, the myoclonus is posthypoxic myoclonus. The invention is also directed to a method for treating dystonia, essential tremor cerebellar tremor, a tic, or chorea, including administering to a patient a compound of formula (I).