Neurokinin-1 Antagonists for Postoperative Nausea and Vomiting

Postoperative nausea and vomiting (PONV) are the second most frequent adverse events after surgery second only to postoperative pain. Despite the advances in antiemetics and implementation of multimodal prophylactic interventions, the clinical management of PONV remains problematic. Neurokinin-1 (NK-1) receptor is a tachykinin receptor found throughout the central and peripheral nervous systems, with a particular affinity towards substance P. NK-1 receptors interact with several parts of the neuronal pathway for nausea and vomiting. This includes the chemoreceptor trigger zone, the gastrointestinal tract, and dorsal motor nucleus of the vagus. NK-1 antagonists are thought to prevent nausea and vomiting by downregulating the emetogenic signals at those points. As more head-to-head trials are conducted between the various anti-emetics, there is emerging evidence that NK-1 antagonists may be more effective in preventing PONV than several other antiemetics currently in use. In this review, we will discuss the pharmacology of NK-1 antagonists, their efficacy in clinical practice, and how they could fit into the framework of PONV management.