BACKGROUND: Postoperative nausea and vomiting (PONV) are common problems in patients undergoing general anesthesia. Ondansetron is widely used for this problems. But, some patients treated with ondansetron do not respond to therapy. We hypothesized that patients with genetic variation in 5-HT_3b receptor and CYP2D6 gene might respond differently to ondansetron treatment.

METHODS: 135 patients undergoing gynecologic surgery were given 4 mg ondansetron 15 min before extubation. The assessment of PONV was performed during < 2 hours and 2-24 hours. DNA was extracted from blood and was analyzed by using restriction fragment-length polymorphism (RFLP) and site-specific PCR.

RESULTS: In 5-HT_3b AAG deletion mutation, the incidence of nausea and vomiting < 2 hr were 25% and 12.5% for wild, 23.4% and 12.2% for heteromutant. The incidence of nausea and vomiting 2-24 hr were 3.2% and 1.1% for wild, 4.9% and 2.4% for heteromutant. This showed no significant differences between two groups. In CYP2D6*10 mutation, the incidence of nausea and vomiting < 2 hr were 28.6% and 19.6% for wild, 22.8% and 8.8% for heteromutant and 23.5% and 5.9% for homomutant. The incidence of nausea and vomiting 2-24 hr were 5.4% and 1.8% for wild, 3.2% and 1.6% for heteromutant, 0% and 0% for homomutant. This showed no significant differences among three groups.

CONCLUSIONS: The incidence of PONV were not different among the genotype of CYP2D6*10 and 5HT_3b AAG mutation.