Broad spectrum antiemetic effects of CP-122,721, a tachykinin NK1 receptor antagonist, in ferrets

The potent, selective, tachykinin NK1 receptor antagonist, CP-122,721 ([(+)-(2S,3S)-3-(2-methoxy-5-trifluoromethoxybenzyl)amino- 2-phenylpipelidine]), at 0.01-1 mg/kg, s.c. reduced retching and vomiting elicited by loperamide, copper sulfate, ipecac syrup and cisplatin in a dose-dependent manner. ID50 values after subcutaneous administration ranged from 0.02 mg/kg (loperamide) to 0.08 mg/kg (ipecac). Oral CP-122,721 reduced cisplatin-induced emesis with an ID50 of approximately 0.08 mg/kg. The less active (2R,3R)-enantiomer, CP-132,687, did not significantly suppress retching or vomiting induced by any of the emetogens. These data support the hypothesis that CP-122,721 blocks emesis by a specific action at tachykinin NK1 receptors. Its broad spectrum of antiemetic activity suggests a central site of action.