Provided is a novel compound having useful pharmacological action for treating cardiac failure and shock, without increasing heart rate, and a phamacetical composition comprising same.Provided is a diphenylmethylpiperazine derivative represented by the following formula [I] or its phamacetically acceptable salt, and a phamacetical composition comprising same.(wherein, R1 represents a hydrogen atom or a hydroxyl group, R2 represents a hydrogen atom, a halogen atom, a hydroxyl group, a C1-5 alkyl group or a C1-5 alkoxyl group, but provided that R1 is a hydroxyl group, R2 is a chlorine atom, is excluded.)本發明是提供一種不增加心搏數,而對於治療心臟衰竭或休克有用的具有藥理作用的新穎化合物,及使用該化合物的醫藥組成物。本發明是關於下述通式[I]表示的二苯基甲基哌衍生物或其在藥學上可容許的鹽及含有該衍生物或其鹽之醫藥組成物。(式中,R1表示氫原子或羥基。R2表示氫原子、鹵原子、羥基、碳數1至5的烷基,或碳數1至5的烷氧基。但,R1是羥基,R2是氯原子的情況除外)。由於本案的圖為實驗數據,並非本案的代表圖。故本案無指定代表圖。
