Patent ID: 8338442

Claim:
A method of treating restless legs syndrome comprising orally or parenterally administering a therapeutically effective amount of an opioid κ receptor agonist compound represented by the following Formula (I): wherein represents a single bond; R 1 represents C 4 -C 7 cycloalkylalkyl or cyclopropylmethyl; R 2 represents hydroxy; R 3 represents hydroxy; A represents —XC(═Y)— (wherein X represents NR 4 ; Y represents O; R 4 represents C 1 -C 5 linear or branched alkyl); B represents C 2 linear acyclic unsaturated hydrocarbon containing 1 double bond; R 5 represents an organic group having the following skeleton: (wherein Q represents —O—); R 6 and R 7 cooperatively represent —O—; and R 8 hydrogen; said Formula (I) includes (+) isomer, (−) isomer and (±) isomer, or a pharmaceutically acceptable acid addition salt thereof to a patient in need thereof.