(RS)-[2-(3,4-dimethoxyphenyl)ethyl][2-hydroxy-3-(3-methylphenoxy)propyllamine having the formula (IA), or a pharmaceutically acceptable salt thereof for the formulation of a pharmaceutical composition is useful for the prophylaxis and/or the treatment of hyperkinetic movement disorders associated with Huntington's disease, Wilson's disease, Tourette syndrome, restless leg syndrome, and tardive dyskinesia.