The present invention provides a pharmaceutical composition for use as an NPY Y5 receptor antagonist comprising a compound of the formula (I): wherein R1 is lower alkyl, cycloalkyl or the like, R2 is hydrogen, lower alkyl or the like, n is 1 or 2, X is lower alkylene, lower alkenylene, arylene, cycloalkylene or the like, Y is CONR7, CSNR7, NR7CO, NR7CS or the like, Z is lower alkyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl or the like and R7 is hydrogen or lower alkyl, prodrug, pharmaceutically acceptable salt or solvate thereof.