[Postoperative pain management following orthognathic surgery in consideration of individual differences--is the antinociceptive effect of fentanyl related to the genotype involving nucleotide at OPRM1?].

We experience individual differences in pain and sensitivity to analgesics clinically. Genetic factors are known to influence individual difference. Polymorphisms in the human OPRM1 gene, which encodes the micro-opioid receptors, may be associated with the clinical effects of opioid analgesics. The study demonstrated whether any of five common single nucleotide polymorphisms (SNPs) of the OPRM1 gene could affect the antinociceptive effect of fentanyl. Fentanyl was less effective in subjects with the G allele of the OPRM1 A118G SNP than those with the A allele, and subjects with the G allele required more fentanyl for adequate postoperative pain control than those with the A allele. In the future, identifying SNPs might give us information to modulate the analgesic dosage of opioid individually for better pain control.