PROBLEM TO BE SOLVED: To provide a compound having the activity to inhibit the discharge ability of a multiple drug discharge pump, and a pharmaceutical composition comprising the compound as an active ingredient.SOLUTION: The present invention provides a compound represented by general formula (I) [where R1 is a thiazole group or an adamantyl group in which one hydrogen atom is optionally substituted with an alkyl group having 1 to 4 carbon atoms, or an alkyl group having 3 to 6 carbon atoms, X is a hydrogen atom or a halogen atom, R2 is an amino group or a hydrogen atom, n is an integer of 1-4, R3 is an amino group or an imidazole group in which one hydrogen atom is optionally substituted with an amidino group] or its physiologically acceptable salt, or their solvates.SELECTED DRAWING: NoneCOPYRIGHT: (C)2017,JPO&INPIT【課題】多剤排出ポンプの排出能を阻害する活性を有する化合物、及び当該化合物を有効成分とする医薬用組成物の提供。【解決手段】一般式(I)[式中、R1は、1個の水素原子が炭素原子数1~4のアルキル基で置換されていてもよいチアゾール基、アダマンチル基、又は炭素原子数3~6のアルキル基を表し、Xは、水素原子又はハロゲン原子を表し、R2は、アミノ基又は水素原子を表し、nは1~4の整数を表し、R3は、1個の水素原子がアミジノ基で置換されていてもよいアミノ基又はイミダゾール基を表す。]で表される化合物若しくはその生理学的に許容される塩、又はそれらの溶媒和物。[化1]【選択図】なし