Observational study of the effect of μ-opioid receptor genetic polymorphism on intrathecal opioid labor analgesia and post-cesarean delivery analgesia

Effect of CYP3A4*18B polymorphisms and interactions with OPRM1 A118G on postoperative fentanyl requirements in patients undergoing radical gastrectomy

“…The exact functional significance of the CYP3A4*18B polymorphism requires additional studies using different drugs in large sample sizes. In the present study, no correlation was detected between OPRM1 A118G and fentanyl dose at postoperative 24 and 48 h, consistent with studies on labor analgesia and cancer pain (17,18). However, results of this study are inconsistent with findings of other studies (14-16) which found that fentanyl was less effective in subjects with the G allele of the OPRM1 A118G and these individuals required more fentanyl for adequate postoperative pain control compared with those with the A allele.…”

“…A number of factors, including the character and intensity of external pain stimuli, age, gender, weight and genetic variation, may affect analgesic requirements. Among these, the contribution of variations in the CYP3A4 and OPRM1 genes has attracted considerable attention (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)24). The CYP3A4*18B polymorphism was identified to be associated with significant variability in fentanyl consumption 48 h following radical gastrectomy in Chinese Han patients.…”

“…Authors have reported that subjects with the G allele of the OPRM1 A118G SNP were less sensitive to fentanyl or that the fentanyl dose was greater compared with AA subjects in patients with postoperative pain or labor analgesia (14)(15)(16). However, results of the additional three studies on this association were not consistent with these observations (17)(18)(19).…”

Pharmacogenetics and Obstetric Anesthesia and Analgesia

“…In a North-American cohort, the effect of the A118G polymorphism on the duration of intrathecal fentanyl analgesia in early labor and found no difference between genotypes 68 . The severity of nausea, pruritus or incidence of vomiting was also not different between genetic groups.…”

“…The response to an intrathecal solution containing morphine and fentanyl for post-Cesarean analgesia according to OPRM1 genotype was evaluated in a North-American cohort 68 . There was no difference in the duration of spinal morphine analgesia or need for analgesic supplementation over 72 hours in women carrying the minor allele (G118).…”