Conivaptan [YM 087], a benzazepine derivative, belongs to a series of highly potent, orally active arginine vasopressin V1and V2receptor antagonists that are being developed by Yamanouchi.Yamanouchi licensed conivaptan to Warner-Lambert for co-development and marketing in the Americas, Europe and Africa. In return, Yamanouchi has rights to market atorvastatin in Japan. In June 2000, Warner-Lambert merged with Pfizer. The resulting company retained the Pfizer name. However, Yamanouchi and Pfizer discontinued the co-development and marketing agreement for conivaptan. Yamanouchi is continuing the independent development of conivaptan in the US and Europe.Yamanouchi is developing an oral drug delivery formulation of conivaptan for administration in patients with chronic heart failure. The company has initiated the ADVANCE (A Dose evaluation of a Vasopressin ANtagonist in CHF patients undergoing Exercise) trial, a double-blind, multicentre trial in which 345 patients with heart failure will receive placebo or one of three doses of conivaptan for 12 weeks and their functional capacity will be assessed.[1]Conivaptan demonstrated a potent diuretic effect in animal studies.