What is the most common first-line antiemetic for postoperative nausea and vomiting?

Ondansetron is recognized as the most common first-line antiemetic for postoperative nausea and vomiting due to its effectiveness as a selective serotonin 5-HT3 receptor antagonist. It works by blocking serotonin receptors in the central nervous system and the gastrointestinal tract, which are involved in the vomiting reflex, particularly following surgery or chemotherapy.

This action helps to significantly reduce the incidence of nausea and vomiting, making it a preferred choice in the postoperative setting. Its rapid onset and relatively few side effects compared to other antiemetics further solidify its position as the go-to medication for this particular application.

While other agents like promethazine, granisetron, and aprepitant are also used in various scenarios, they each have different mechanisms of action and are not typically first-line for postoperative nausea and vomiting. For example, while granisetron is similar to ondansetron in that it also works on the 5-HT3 receptors, ondansetron has more extensive clinical support for use specifically in postoperative settings. Promethazine, on the other hand, tends to have more sedative effects and is used more broadly for nausea rather than being specific for surgical patients. Aprepitant, which acts on the neurokinin-1 receptor,