• Is a neurokinin-1 receptor antagonist
• Significantly reduced vomiting after cisplatin infusion
• Reduced vomiting when given before and after vomiting began

The act of vomiting is primarily a protective reflex, removing noxious substances from the stomach. However, emesis is also found in a wide range of clinical disease processes and can lead to life-threatening problems. Treatment of emesis can reduce distress and prevent serious complications. In dogs, emesis is thought to be regulated by nuclei located in the brainstem, within the reticular formation of the medulla oblongata and including the nucleus tractus solitarius; this area is referred to as the emetic center. Several different afferent pathways from the cerebral cortex provide stimulation to the emetic center. Maropitant, a novel neurokinin-1 receptor antagonist, was developed to manage emesis. This study was designed to evaluate the efficacy of maropitant to treat and prevent emesis caused by IV infusion of a chemotherapeutic dose of cisplatin. In 1 set of trials, 24 dogs were given cisplatin and after the first emetic episode were given either saline solution or maropitant (1 mg/kg) by SC injection. Dogs were assessed for 6 hours after the infusion. Significantly fewer vomiting episodes were observed for the maropitant-treated dogs, and the mean time to cessation of emesis was significantly shorter. In another trial, dogs were either given a placebo or maropitant at 1, 2, or 3 mg/kg by mouth. Cisplatin was infused 19 hours after treatment. Maropitant-treated dogs had significantly fewer emetic events (means, 2.7, 1.1, and 0.5) compared with the placebo-treated dogs (mean, 20.3).

Study by Pfizer Ltd, Sandwich, Kent UK Efficacy of maropitant for treatment and prevention of emesis caused by intravenous infusion of cisplatin in dogs. de la Puente-Redondo VA, Tilt N, Rowan TG, Clemence RG. AM J VET RES 68:48-56, 2007.