This invention relates to an analgesic drug comprising a compound represented by the following formula (I) or (II), wherein R1 is a C1-6-alkoxy group or a C1-6-haloalkoxy group; R2 is a hydrogen atom; and R is an indazolyl group substituted with a halogen atom; a substituted or unsubstituted phenyl group; a pyrazolyl group; or a substituted or unsubstituted aralkyl group; or a salt thereof, or a solvate thereof.