What is the mechanism of action of maropitant?

Maropitant functions as a neurokinin-1 (NK-1) receptor antagonist, which is essential for its effectiveness in managing nausea and vomiting in animals, particularly in dogs and cats. The NK-1 receptors are part of the substance P pathway, which is involved in the vomiting reflex. By blocking these receptors, maropitant prevents substance P from binding, thereby inhibiting the emetic response and providing relief from nausea. This mechanism distinguishes maropitant from other antiemetic drugs that may act on different receptors, such as those for dopamine, histamine, or serotonin. The specific action on the NK-1 receptor makes maropitant particularly useful for the treatment of motion sickness and for managing emesis associated with chemotherapy or other causes.