Casopitant [1-piperidinecarboxamide,4-(4-acetyl-1-piperazinyl)-N-((1R)-1-(3,5-bis(trifluoromethyl)phenyl)-ethyl)-2-(4-fluoro-2-methylphenyl)-N-methyl-(2R,4S)] is a potent and selective antagonist of the neurokinin-1 (NK1) receptor, developed for the prevention of chemotherapy-induced nausea and