Eigenschaften/Wirkungen: three classes of antiemetic drugs, serotonin antagonists (e.g. ondansetron), corticosteroids (e.g. dexamethasone), and dopamine antagonists (e.g. droperidol) have similar efficacy against postoperative nausea and vomiting, with a relative risk reduction of ~25%. Moreover, they act independently and, when used in combination, have additive effects (1).