A morphinan derivative represented by general formula (I) (in the formula, R1 represents a hydrogen atom, an optionally substituted C1-6 alkyl group, or the like, R2 and R3 are the same or different and represent a hydrogen atom, a hydroxy group, or the like, R4 represents a hydrogen atom, a halogen atom, a hydroxy group, or the like, R5 represents a hydrogen atom, hydroxy group, or the like, R6 represents a hydrogen atom, a C1-6 alkyl group, or the like, R7 and R8 are the same or different and represent a hydrogen atom, a C1-6 alkyl group, or the like, R9 represents a hydrogen atom, a C1-6 alkyl group, an optionally substituted C6-10 aryl group, or the like, X represents a nitrogen atom or the like, Y represents an oxygen atom or the like, and n represents an integer of 0-3), a tautomer, a stereoisomer, a deuterium substitution product, or a pharmaceutically acceptable salt of the compound or a solvate of these, and a medicine, an analgesic, and an antipruritic having these as an active ingredient.