CYP2D6 and Huntington disease: The information on the effects of impaired CYP2D6 metabolism of deutetrabenazine from this study together with the data from PK comparisons to tetrabenazine [5, 6] and population PK analyses (data on file, Teva Pharmaceutical Industries Ltd) were used to establish the doses in the phase 3 efficacy and safety studies which supported registration of deutetrabenazine (Austedo) as a treatment for chorea for Huntington’s disease and tardive dyskinesia [1, 3, 4].