Background Remifentanil is a rapid onset, ultra-short acting opioid that displays a stabilising effect on the maternal circulation during caesarean section under general anaesthesia while its effects on postnatal adaptation of the neonate are usually only modest.

Purpose The aim of our study was to evaluate the possible effect of ABCB1 and OPRM1 polymorphisms on the therapeutic efficacy and neonatal safety of remifentanil in women undergoing elective caesarean section under general anaesthesia.

Material and methods Women undergoing general anaesthesia for caesarian section were administered remifentanil bolus (1 µg/kg iv) 30 s prior to the induction of standardised general anaesthesia. The ABCB1 (rs2032582, rs1045642) and OPRM1 (rs1799971) polymorphisms were analysed from maternal peripheral blood.

Results Basal haemodynamic and demographic parameters in the study population (n = 54) were similar in the subgroups. The median±SD increase in systolic blood pressure at 5 min from baseline was practically completely abolished in homozygous carriers of ABCB1 variants in comparison with wild-type subjects: -2.67 ± 25.0 vs. 16.57 ± 15.7 mm Hg, p < 0.05, for rs2032582, and 2.00 ± 23.9 vs. 22.13 ± 16.8 mm Hg, p < 0.05, for rs1045642. There was a trend towards better stabilisation of the haemodynamic parameters in OPRM1 wild-type homozygous subjects in comparison with carriers of the variant allele carriers. Neonatal safety was not statistically different among genotype subgroups, however, clinical differences were clearly pronounced. While no neonate belonging to ABCB1 wild-type homozygous or OPRM1 variant allele carrying mothers needed any resuscitative measure, 10.5% of neonates belonging to OPRM1 wild-type homozygous mothers received early resuscitative support similarly as neonates belonging to mothers carrying variants of rs2032582 and rs1045642 (11.1% and 12.5%, respectively).

Conclusion Significantly decreased stabilising effects of remifentanil were observed in ABCB1 wild-type mothers, while adaptation of their neonates was clinically worse in ABCB1 variant allele carriers. A similar trend was noted for OPRM1 wild-type homozygote mothers for both haemodynamic effects and neonatal safety.

References and/or Acknowledgements

1. Hwang IC, Park JY, Myunk SK, et al. OPRM1 A118G gene variant and postoperative opioid requirement: a systematic review and meta-analysis. Anesthesiology 2014;121:825–34

References and/or AcknowledgementsNo conflict of interest.