The present invention provides a combined drug for an injectable depot formulation having a superior effect of preventing and/or treating polycystic kidney disease. More specifically, the present invention relates to a drug for preventing and/or treating polycystic kidney disease, which is an injectable depot formulation comprising a particle containing tolvaptan or a prodrug thereof and a somatostatin analogue. The present invention also relates to a method for preventing and/or treating polycystic kidney disease using the drug.本發明提供一種用於可注射式積存調配物的結合藥物,其具有優異的預防及/或治療多囊腎病效應。更精確來說,本發明係關於一種用於預防及/或治療多囊腎病的藥物,其係一種包括含托伐普坦或其前藥的顆粒與體抑素類似物之可注射式積存調配物。本發明亦關於一種使用該藥物來預防及/或治療多囊腎病的方法。