Abstract: A method of treating a human patient afflicted with Huntington's disease, comprising periodically orally administering to the patient a pharmaceutical composition comprising pridopidine, its analog or a pharmaceutically acceptable salt thereof.

Abstract: The invention provides a method of treating a subject afflicted with a drug-induced movement disorder including levodopa-induced dyskinesia comprising periodically administering to the subject in need thereof an amount of pridopidine effective to treat the subject. The invention further provides a method of treating a subject at risk of developing a drug-induced movement disorder, including levodopa-induced dyskinesia. The invention also provides pharmaceutical compositions suitable for carrying out these methods and packages containing such pharmaceutical compositions.

Abstract: The invention provides a method of treating a subject afflicted with fragile X syndrome (FXS) or a FXS related disorder, comprising periodically administering to the subject a pharmaceutical composition comprising an amount of pridopidine effective to treat the subject.

Abstract: This invention provides an isolated compound having the structure: or a salt thereof. The invention also provides for a process for preparing 4-(3-(methylsulfonyl)phenyl)-1-propylpiperidin-4-ol, 1-(3,3-bis(3-(methylsulfonyl)phenyl)propyl)-4-(3-(methylsulfonyl) phenyl)piperidone, 1,4-bis((3-(1-propylpiperidin-4-yl)phenyl)sulfonyl)butane, (3R,4S)-4-(3-(methylsulfonyl)phenyl)-1-propylpiperidin-3-ol, 4-(3-(methylsulfonyl)phenyl)-1-propylpiperidine 1-oxide, 1-(2-methylpentyl)-4-(3-(methylsulfonyl)phenyl)piperidine, 4-(3-(methylsulfinyl)phenyl)-1-propyl-1,2,3,6-tetrahydropyridine, and 4-(3-(methylsulfonyl)phenyl)-1-propyl-1,2,3,6-tetrahydropyridine. This invention also provides an impurity or a salt thereof for use, as a reference standard to detect trace amounts of the impurity in a pharmaceutical composition comprising pridopidine or a pharmaceutically acceptable salt thereof.