significant difference in postoperative analgesic requirements was found between the subjects with the combined T/T and T/C genotype and subjects with the C/C genotype in the rs2952768 SNP. Interestingly, the subjects with the C/C genotype required significantly more analgesics than the subjects with the combined T/T and T/C genotype in the rs2952768 SNP (t110=−2.340, P=0.021), a pattern similar to the one observed in the subjects who underwent cosmetic orthognathic surgery. Total analgesic use, equipotent with systemic fentanyl, during the 24-h postoperative period was 0.359±0.073, 0.397±0.068 and 0.741±0.169 μg kg–1 (log transformed; mean±s.e.m.) in the subjects with the T/T, T/C and C/C genotypes, respectively (Figure 2b).
