Substance P binds to the Neurokinin-۱ (NK-۱) receptors found in the emetic center of the central nervous system (CNS) to induce emesis. Maropitant is a selective NK-۱ receptor antagonist that inhibits the binding of substance P to NK-۱ receptors and is commonly used to prevent and treat vomiting in dogs. This review study aimed to discuss and analyze the therapeutic potential of substance P (Neurokinin-۱ receptor) antagonist with a particular focus on the drug
maropitant in canine medicine. A systematic literature review was performed to identify the existing literature on the subject during the past ۲۰ years (۲۰۰۱-۲۰۲۱) using such databases as ScienceDirect, PubMed, Scopus, and Google Scholar. The initial search identified ۱۷۳ articles; however, ۴۱ articles were selected for further analysis, based on the specific inclusion and exclusion criteria. Studies have already confirmed the role of substance P and NK-۱ receptors in central pain processing, intestinal smooth muscle contraction, vasodilation, and neurogenic inflammation. Maropitant is one of the most effective veterinary
antiemetic drugs that work well against peripheral and central stimuli that trigger the vomiting center. It has been already demonstrated that the therapeutic efficacy of
maropitant for managing acute vomiting in dogs is associated with pancreatitis, gastritis, and parvoviral enteritis. It can also prevent and treat chemotherapy-induced emesis and delay the signs of nausea and adverse gastrointestinal effects. Regarding the broad-spectrum
antiemetic activity of maropitant, it can be recommended for managing uremic vomiting in dogs. In addition, it has also exhibited an anesthetic sparing effect since the dogs treated with
maropitant require a slightly lower percentage of isoflurane as an inhalational anesthetic. The NK-۱ receptors are also identified in different areas of the pain pathways. Therefore, NK-۱ receptor antagonists might be effective for managing visceral pain. However, further studies are required to establish the broad therapeutic potential of NK-۱ receptor antagonist drugs, such as
maropitant in canine medicine. It has been shown that the pain associated with the subcutaneous administration of
maropitant is due to metacresol, a preservative used in some formulations. Therefore, the side effects can be eliminated by developing novel
maropitant formulations specifically for dogs.