Anti-emetic prophylaxis with oral tropisetron and/or dexamethasone

The corticosteroid dexamethasone and the serotonine3 -antagonist tropisetron are both effective drugs for the prophylaxis of post-operative nausea and vomiting (PONV) when given intravenously. The aim of this trial was to evaluate the oral use of both drugs as part of a routine oral premedication and to compare their single and combined effectiveness.

In this randomized, placebo-controlled, double-blind study, 320 inpatients with a moderate-high risk of PONV (> or = 40% according to two validated risk scores) received an oral premedication 1-2 h pre-operatively with placebo, a fixed dose of tropisetron 5 mg, dexamethasone 8 mg, or a combination of both drugs. A standardized general anaesthesia was performed, including benzodiazepine premedication, propofol, rocuronium, desflurane in air/O2, fentanyl or sufentanil followed by a continuous infusion of remifentanil. Post-operative analgesia and anti-emetic rescue medication were standardized. The main outcome measures were the severity of PONV within the first 24 h (rated by a standardized scoring algorithm). The incidence of PONV was used as the secondary outcome.

Data from 310 patients were analyzed. The mean severity score in the placebo-, tropisetron-, dexamethasone- and the combined-groups was 1.37, 0.8, 0.8 and 0.38, respectively. The incidence of PONV of any severity was 59.2%, 37.5%, 40% and 22.8%, respectively. The reduction of the incidence and the severity of PONV were statistically significant with all three interventions. Results from additional analyses suggested that both drugs were equally effective and that there was a simple additive effect of tropisetron and dexamethasone compared with placebo.

Oral tropisetron and dexamethasone were both equally effective in reducing the severity and incidence of post-operative nausea and vomiting. The latter could be reduced by approximately 35% in a population of moderate-high risk for PONV. Both drugs had an additive effect. However, even in the combination group there still remained an unacceptably high incidence of PONV of more than 20%. This highlighted the need for a multimodal anti-emetic approach in high-risk patients and the importance of treatment of PONV.