H+,K+-ATPase inhibitor (pIC50 = 6 in human recombinant ion-leaky assays); more potent in acidic conditions. Highly selective for H+,K+-ATPase in vitro; displays no activity at Na+,K+-ATPase. Also displays selectivity for H+,K+-ATPase over a range of 50 receptors and ion channels (IC50 > 10 μM). Inhibits gastric acid secretion in rat and dog models.