CP-66,948: an antisecretory histamine H2-receptor antagonist with mucosal protective properties.

CP-66,948 is a histamine H2-receptor antagonist with gastric antisecretory activity and mucosal protective properties. The affinity of CP-66,948 for the guinea pig atria histamine H2-receptor is 15 times greater than that of cimetidine and seven times greater than that of ranitidine. In vivo, the ED50 value for inhibition of gastric acid secretion in pylorus-ligated rats is 2 mg/kg intraduodenally, and in histamine or pentagastrin-stimulated Heidenhain pouch dogs the antisecretory ED50 values are 0.3 mg/kg per os and 1.0 mg/kg per os, respectively. CP-66,948 also inhibits ethanol-induced gastric hemorrhagic lesions in rats following either oral or systemic administration (ED50 values of 12 mg/kg per os and 6 mg/kg subcutaneously). In addition, the mucosal protective activity is independent of prostaglandin synthesis. CP-66,948 inhibits gastric acid secretion in man, and its mucosal protective activity may provide additional benefits in peptic ulcer therapy.