The present invention relates to extended-release pharmaceutical compositions comprising about 5 to about 30 mg of d6-tetrabenazine and a sustained-release polymer which is a polyvinyl acetate-polyvinyl pyrrolidone mixture or a poly(ethylene oxide) polymer, and uses of such compositions as medicaments to inhibit vesicular monoamine transporter 2 (VMAT2) activity in a subject for the treatment of chronic hyperkinetic movement disorders.