Solid pharmaceutical compositions with high drug loading are provided. A formulation useful for the solid pharmaceutical composition includes valbenazine, or a pharmaceutically acceptable salt thereof, silicified microcrystalline cellulose, isomalt, hydroxypropyl methylcellulose, partially pregelatinized maize starch, and magnesium stearate.本發明提供具有高藥物載量之固體醫藥組合物。適用於該固體醫藥組合物之調配物包括戊苯那嗪(valbenazine)或其醫藥學上可接受之鹽、矽化微晶纖維素、異麥芽酮糖醇、羥丙基甲基纖維素、部分預糊化玉米澱粉及硬脂酸鎂。