Disclosed are a fused tricyclic γ-amino acid derivative and a medical use thereof, in particular, the present invention relates to a fused cyclic γ-amino acid derivative as shown in general formula (I), or a stereoisomer, solvate, metabolite, prodrug, pharmaceutically acceptable salt or eutectic thereof, a pharmaceutical composition containing same, and the use of a compound or the composition in the field of analgesia, wherein the definitions of each substituent in general formula (I) are the same as the definitions in the description.