An N-substituted N-(4-piperininyl)amide derivative represented by the following formula (I): (wherein R
1
represents C
1-6
alkyl, furyl, etc.; R
2
represents amino, acetylamino, ureido, etc.; R
3
represents hydrogen, C
2-8
alkoxycarbonyl, etc.; R
4
represents optionally substituted phenyl, etc.; R
5
represents hydroxyl, benzyloxy, etc.; R
6
represents hydrogen or methyl; and m is 1 or 2) or a salt of the derivative, and an analgesic containing the derivative or salt.
An N-substituted N-(4-piperininyl)amide derivative represented by the following formula (I): (wherein R1 represents C1-6 alkyl, furyl, etc.; R2 represents amino, acetylamino, ureido, etc.; R3 represents hydrogen, C2-8 alkoxycarbonyl, etc.; R4 represents optionally substituted phenyl, etc.; R5 represents hydroxyl, benzyloxy, etc.; R6 represents hydrogen or methyl; and m is 1 or 2) or a salt of the derivative, and an analgesic containing the derivative or salt.