The present invention relates to a pharmaceutical composition for prevention or treatment of a muscular disease, the composition comprising dimenhydrinate, harmol and/or calcium pantothenate as active ingredients. Application of dimenhydrinate, harmol, and calcium pantothenate individually has an effect of promoting myoblast proliferation and differentiation. In particular, the combination thereof has the effect of synergistically increasing the effect of promoting myoblast proliferation and differentiation. Thus, dimenhydrinate, harmol and/or calcium pantothenate may be usefully used alone or in combination for the prevention or treatment of muscular diseases, in particular sarcopenia.