The present invention provides a drug for treating cocaine addiction or preventing the relapse of the same. Specifically, the present invention provides a drug for treating cocaine addiction or preventing the relapse of the same containing (R)-2-{3-[1-(5-methyl-1,2,3,4-tetrahydronaphthalen-1-yl)piperidin-4-yl]-2,3-dihydro-2-oxo-benzimidazol-1-yl}-N-methylacetamide or a pharmaceutically acceptable salt thereof.
