A proton pump inhibitor; inhibits the gastric H+/K+ ATPase (IC50 = 72 nM); activated more rapidly and over a greater pH range than other proton pump inhibitors; inhibits gastric acid secretion in pylorus-ligated rats and a rat model of gastric fistula at 30 mg/kg; inhibits the growth of several strains of H. pylori in vitro (MIC50s = 1.57-3.13 μg/mL)