Prophylactic antiemetic efficacy of granisetron or ramosetron in patients undergoing thyroidectomy

Thyroidectomy is associated with a high incidence of postoperative nausea and vomiting (PONV), ranging from 60% to 84%. We conducted this study to compare the antiemetic effects and safety of granisetron 20 micro g/kg and ramosetron 4 micro g/kg in patients undergoing elective thyroidectomy under standard anaesthetic technique.

One hundred and thirteen patients were randomized to receive placebo (n = 41), granisetron 20 nug/kg (n = 36) or ramosetron 4 micro g/kg (n = 36) intravenously over 2-5 minutes immediately before the induction of anaesthesia. The incidence of PONV, nausea severity score (NSS), adverse events and the need for rescue antiemetics were assessed during the first 1 hour (0-1 h) and following 23 hours (1-24 h) after anaesthesia.

During the first hour after anaesthesia, the incidence of PONV was 36.6% for placebo, 11.1% for granisetron (p = 0.012 vs placebo) and 25.0% for ramosetron. During 1 hour to 23 hours after anaesthesia, the incidence of PONV was 51.2% for placebo, 30.6% for granisetron and 41.7% for ramosetron. There were no significant differences between the three groups. Overall (0-24 h), the corresponding incidence of PONV were 61.0%, 30.6% and 50.0%, respectively, showing a significantly lower value in the granisetron group than in the placebo group (p = 0.008). The incidence of vomiting and rescue antiemetic requirement during the first 24 hours after anaesthesia was significantly lower with the granisetron group than with placebo (p = 0.021 and 0.030, respectively). The most common adverse events in the three groups were headache and dizziness.

Only granisetron 20 micro g/kg was superior to placebo for the prevention of PONV after thyroidectomy.