Postoperative nausea and vomiting: The role of the dopamine D2 receptor TaqIA polymorphism.

BACKGROUND: The risk of developing postoperative nausea and vomiting (PONV), apart from conventional risk factors, probably includes a genetic background. OBJECTIVES: We examined the association of the DRD2 TaqIA polymorphism with PONV in a high-risk cohort of patients. DESIGN: A prospective, double-blind observational trial. SETTING: Single-centre primary care in Western Germany. PATIENTS: A total of 306 patients undergoing elective strabismus surgery under anaesthesia with etomidate/alfentanil/mivacurium (induction) and sevoflurane in air (maintenance). MAIN OUTCOME MEASURES: Nausea as well as retching/vomiting was recorded for 24 h postoperatively. The DRD2 TaqIA polymorphism (rs1800497) was genotyped using a Taqman assay and the relationship between DRD2 TaqIA polymorphism and PONV was examined by univariate and multivariate analysis. RESULTS: Regarding known risk factors for developing PONV, no patient with the A1A1 genotype (n = 15) had a history of PONV, while A1A2 carriers (n = 115) and A2A2 carriers (n = 176) had a history of PONV in 22.6 and 10.8% of patients, respectively (P = 0.005). Overall, the incidence of nausea was 40.1% and the incidence of vomiting/retching was 32.7%. Univariate analysis showed that postoperative nausea was not associated with TaqIA genotypes, but the incidence of retching/vomiting in A1A2 and A2A2 genotypes was more than 34% compared with zero in A1A1 genotypes (P = 0.022). Age, sex, smoking status and a history of PONV were independent predictors for nausea as well as for retching/vomiting, as expected, while DRD2 TaqIA polymorphism showed no independent significant impact. CONCLUSION: In a white cohort, the TaqIA A2 allele is significantly associated with a history of PONV, which may explain the increased incidence of PONV but has no further independent influence. TRIAL REGISTRATION: German registry of clinical trials identifier: DRKS00005681.