Effect of ADRA2A gene polymorphisms on the anesthetic and analgesic effects of dexmedetomidine in Chinese Han women with cesarean section

Genetic polymorphisms are associated with individual susceptibility to dexmedetomidine

Introduction: Dexmedetomidine (DXM) is widely used as an adjuvant to anesthesia or a sedative medicine, and differences in individual sensitivity to the drug exist. This study aimed to investigate the effect of genetic polymorphisms on these differences. Methods: A total of 112 patients undergoing hand surgery were recruited. DXM 0.5 μg/kg was administered within 10 min and then continuously injected (0.4 μg/kg/h). Narcotrend index, effective dose and onset time of sedation, MAP, and HR were measured. Forty-five single nucleotide polymorphisms (SNPs) were selected for genotype. Results: We observed individual differences in the sedation and hemodynamics induced by DXM. ABCG2 rs2231142, CYP2D6 rs16947, WBP2NL rs5758550, KATP rs141294036, KCNMB1 rs11739136, KCNMA1 rs16934182, ABCC9 rs11046209, ADRA2A rs1800544, and ADRB2 rs1042713 were shown to cause statistically significant (p < 0.05) influence on the individual variation of DXM on sedation and hemodynamics. Moreover, the multiple linear regression analysis indicated sex, BMI, and ADRA2A rs1800544 are statistically related to the effective dose of DXM sedation. Discussion: The evidence suggests that the nine SNPs involved in transport proteins, metabolic enzymes, and target proteins of DXM could explain the individual variability in the sedative and hemodynamic effects of DXM. Therefore, with SNP genotyping, these results could guide personalized medication and promote clinical and surgical management.

Effect of dexmedetomidine on oxytocin-induced uterine contraction during optimal caesarean section anaesthesia

Numerous drugs are used during caesarean sections to provide regional and general anaesthesia. Dexmedetomidine has been used in some recent obstetric trials, but there are concerns about postpartum changes in uterine contractions. This study evaluated the effect of dexmedetomidine on oxytocin-induced uterine contractions in women undergoing caesarean section. Sixty women undergoing caesarean section in Lianyungang Second People's Hospital were randomly assigned to dexmedetomidine (group D, n = 30) or saline (group C, n = 30) groups. Equal volumes of saline or dexmedetomidine were administered intravenously (IV). During the intraoperative delivery of the foetus and placenta, oxytocin was administered to promote contractions. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were compared. The Ramsay scale was used to assess sedation, while the Tsai and Chu methods assessed shivering. Adverse intraoperative events were observed. All variables fluctuated significantly after anaesthesia onset in both groups but were most pronounced in group D. The VAS, Ramsay and shivering scores were significantly lower in group D compared to group C. During rapid IV infusion of oxytocin after foetal delivery, the incidence of nausea, vomiting, chest tightness and hypotension was significantly lower in group D than in group C.

A pilot study of ADRA2A genotype association with doses of dexmedetomidine for sedation in pediatric patients

STUDY OBJECTIVE

Dexmedetomidine is titrated to achieve sedation in the pediatric and cardiovascular intensive care units (PICU and CVICU). In adults, dexmedetomidine response has been associated with an ADRA2A polymorphism (rs1800544); CC genotype is associated with an increased sedative response compared with GC and GG. To date, this has not been studied in children.

DESIGN

We conducted a pilot study to determine whether ADRA2A genotype is associated with dexmedetomidine dose in children.

MEASUREMENTS AND MAIN RESULTS

Forty intubated PICU or CVICU patients who received dexmedetomidine as a continuous infusion for at least 2 days were genotyped for ADRA2A with a custom-designed TaqMan® Assay. Ten (25%) subjects were wildtype (GG), 15 (37.5%) were heterozygous (GC), and 15 (37.5%) were homozygous (CC) variant. The maximum dexmedetomidine doses (mCg/kg/h) were not different between genotype groups CC (1, 0.3-1.2), GC (1, 0.3-1.3), and GG (0.8, 0.3-1.2), (p = 0.37); neither were mean dexmedetomidine doses for these respective genotype groups 0.68 (0.24-1.07), 0.72 (0.22-0.98), 0.58 (0.3-0.94), (p = 0.67).

CONCLUSIONS

These findings did not confirm the results from adult studies where ADRA2A polymorphisms correlate with dexmedetomidine response, therefore highlighting the need for pediatric studies to validate PGx findings in adults prior to implementation in pediatrics.