Dopamine D2 receptor Taq IA polymorphism is associated with postoperative nausea and vomiting

The dopamine D2 receptor (DRD2) is considered to be involved in the development of postoperative nausea and vomiting (PONV). Our aim was to examine the relationship between DRD2 Taq IA polymorphism and the occurrence of PONV. We enrolled 1070 patients who were scheduled to undergo elective surgery under general anesthesia. Patients who vomited or required rescue antiemetics for severe nausea at two time points (within 6 and within 24 h after surgery) were defined as having early and total PONV, respectively. A polymerase chain reaction with confronting two-pair primers (PCR-CTPP) technique was adopted for DRD2 genotyping allele (A1A1, A1A2, or A2A2). The relationship between DRD2 Taq IA polymorphism and the occurrence of PONV was examined by multivariate logistic regression analysis. The incidences of early PONV were 9.0%, 9.3%, and 14.4% in patients with the A1A1, A1A2, and A2A2 alleles, respectively. Sex, nature of the disease, smoking status, type of surgical department, duration of anesthesia, and the DRD2 Taq IA polymorphism were related to the emergence of early PONV. On multivariate analysis, the relative risk associated with the A2A2 allele in comparison with the A1A1 or A1A2 allele was 1.58 (95% confidence interval [CI], 1.05-2.37) for early PONV. The incidences of total PONV were 12.5%, 13.6%, and 17.2% in patients with the A1A1, A1A2, and A2A2 alleles, respectively. Sex, smoking status, type of surgical department, and duration of anesthesia were related to the emergence of total PONV. On multivariate analysis, the relative risk associated with the A2A2 allele in comparison with the A1A1 or A1A2 allele was 1.27 (95% CI, 0.88-1.84) for total PONV. The DRD2 Taq IA polymorphism affected the occurrence of early PONV. Analysis of patients' genetic backgrounds may improve risk-stratification for PONV.