Comparison of Efficacy of Clonidine versus Ondansetron for Prevention of Nausea and Vomiting Post Thyroidectomy: A Double Blind Randomized Controlled Trial.

BACKGROUND AND AIM Postoperative nausea vomiting (PONV) is the most common symptom in patients post thyroidectomy. Literature search shows conflicting results regarding use of clonidine in PONV prophylaxis. We undertook this randomized controlled double blind trial to compare the efficacy of clonidine with dexamethasone versus ondansetron with dexamethasone for PONV prophylaxis in these patients. MATERIALS AND METHODS In this prospective study, 60 consecutive patients posted for thyroidectomy from August 2013 to July 2014, were randomly assigned to two groups, ondansetron (N= 30) (Group A) and clonidine (N= 30) (Group B). Patients received either oral ondansetron 8mg or oral clonidine 150μg as premedication. At the end of surgery, both groups received dexamethasone 8mg intravenously. They were monitored for occurrence of PONV and sore throat for next 24 h. Ramsay sedation scores and total time of analgesia was noted. The primary end point was incidence of PONV in post operative for 24 h. Pearson's chi square test and Students t tests were performed using SPSS for windows version 20 (SPSS Inc., Chicago, IL). RESULTS Baseline characteristics of patients were comparable. A higher proportion of patients in clonidine group developed PONV than ondansetron (36.7% vs 30%; p=0.03). Clonidine group patients experienced early nausea and vomiting (1-2hrs of postoperative period), compared to ondansetron group patients (6-12 h). Ramsay sedation scores at arrival were higher in clonidine group compared to ondansetron group (2.1 ± 0.3 versus 2.0; p=0.003). Total time of analgesia was higher with use of clonidine than ondansetron (919.5 ± 622 mins versus 642 ± 631 mins; p=0.09). Moderate sore throat was seen in 2 out of 30 patients in both groups. No major adverse events were observed in either group. CONCLUSION Ondansetron with dexamethasone group was more effective in controlling PONV after thyroidectomy compared to clonidine with dexamethasone group. However, ramsay sedation scores and total time of analgesia were higher with clonidine than ondansetron.