The effect of oral ondansetron premedication on the postoperative emesis

Abstract

In this study, ondansetron in a dose of 4 mg (tablet) was given to gynaecologic, ear nose-throat (ENT) and ophthalmic patients preoperatively and its efficacy in preventing postoperative emesis was investigated. 62 adult patients aged 16-75 (mean 38.7 ± 2.6) years were divided into two groups. Control group (n = 30) received 1 mg/kg IM pethidine and ondansetron group (n = 32) received 1 mg/kg IM pethidine + 4 mg oral ondansetron for the premedication. Thiopentone and vecuronium were given for induction and O2/N2O/isoflurane for maintenance of anaesthesia to all patients. Nausea, retching and vomiting were assessed as emesis and were evaluated at 0.-10. min, 10.-60. min, 1.-6. h, 6.-12. h and 12.-24. h in postoperative 24 h period and two groups were compared. Incidents of emesis in gynaecologic, ENT and ophthalmologic patients were compared between the two groups. In the control group incidence of emesis was found 50%, 30%, 20% at 1.-6. h, 10.-60. min and 6.12. h, respectively. Ondansetron group had a significantly lower incidence of emesis as 9% in the 0. min to 12. h period following recovery from anaesthesia than the control group (p < 0.01, p < 0.05, p < 0.01). Decrease in emesis was most significant in gynaecologic patients (from 100% to 33.3%, p < 0.01). There was also significant decrease in emesis in ENT patients (from 60% to 10%, p < 0.05). Although the incidence of emesis decreased in ophthalmologic patients given ondansetron, this difference did not reach the level of significance (from 30% to 20%, p > 0.05). As a result, administration of ondansetron preoperatively to gynaecologic, ENT as well as all cases with a history of emesis may be useful for preventing postoperative emesis.