The role of neurokinin-1 receptor antagonists for the management of postoperative nausea and vomiting

Purpose of review To review the characteristics of neurokinin-1 receptor antagonists and their potential role in the management of postoperative nausea and vomiting. Recent findings Neurokinin-1 antagonists compete with substance P, an endogenous ligand with a high density of receptors in the area postrema and the nucleus tractus solitarii, believed to be involved in terminal emetic pathways. Experimental data provide evidence for efficacy against a wide range of peripheral and central emetic stimuli and clinical trials confirm that neurokinin-1 antagonists have significantly higher efficacy against vomiting than all other antiemetics, with relative risk reductions of over 50%. In fact, aprepitant - the first neurokinin-1 antagonist approved by the US Food and Drug Administration - provides superior protection against postoperative vomiting compared with ondansetron, and the same appears to be true for other drugs of this class. However, efficacy against nausea does not appear to be superior to other antiemetics, so that composite outcomes that are driven by nausea (e.g. complete response) disguise the unique anti-vomiting efficacy. Summary Postoperative vomiting can lead to rare but serious complications. Neurokinin-1 receptor antagonists are significantly more efficacious against postoperative vomiting than other antiemetics. Because the benefit in terms of absolute risk reduction is critically dependent on the patient's baseline risk, it is recommended to use a validated risk score to identify patients who will benefit most from prophylaxis using neurokinin-1 receptor antagonists.