The present invention relates to a compound represented by the formula:wherein A is pyridyl group having at least one substituentwherein R1, R2and R3are each a hydrogen atom, a halogen atom, a C1-6alkyl group optionally substituted by halogen or a C1-6alkoxy group optionally substituted by halogen, R4and R6are each a hydrogen atom, a halogen atom or a C1-6alkyl group optionally substituted by halogen, R5is a hydrogen atom, a halogen atom, a C1-6alkyl group optionally substituted by halogen or a C1-6alkoxy group optionally substituted by halogen, and R7is a hydrogen atom or a C1-6alkyl group optionally substituted by halogen or a salt thereof, or a pharmaceutical composition containing the same.本發明係有關下式所示之化合物或其鹽或含有該化合物之醫藥組成物：其中A為具有至少一個取代基之吡啶基其中R1、R2以及R3各自為氫原子、鹵素原子、視需要經鹵素取代之C1-6烷基或視需要經鹵素取代之C1-6烷氧基，R4及R6各自為氫原子、鹵素原子或視需要經鹵素取代之C1-6烷基，R5為氫原子、鹵素原子、視需要經鹵素取代之C1-6烷基或視需要經鹵素取代之C1-6烷氧基，以及R7為氫原子或視需要經鹵素取代之C1-6烷基。
