Patent ID: 8470845

Claim:
A method for relieving or allaying pain, comprising administering an effective amount of one or more morphinan derivatives having a nitrogen-containing heterocyclic group represented by Formula (I): wherein R 1 is C 4 -C 7 cycloalkylalkyl; R 2 and R 3 are hydroxy; —X— is C 2 alkylene constituting a part of the ring structure; Y represents —C(═O)—; k is 2; R 5 s are substituents in the number of k on a cyclic structure, which are two R 5 s bound to adjacent carbon atoms, respectively, cooperatively form benzo or cyclohexano, each of these rings formed with said two R 5 s bound to adjacent carbon atoms being non-substituted or substituted with 1 or more R 6 s; R 6 (s) independently is (are) fluoro or C 1 -C 5 alkyl; R 10 is hydrogen; R 11 and R 12 are bound to form —O—; R 13 and R 14 are hydrogen or a pharmaceutically acceptable acid addition salt thereof.