Review article: the pharmacology of rabeprazole

Rabeprazole sodium is a new substituted benzimidazole proton pump inhibitor with several differences compared with existing proton pump inhibitors. In vitro and animal studies have demonstrated that rabeprazole is a more pote nt inhibitor of H+,K+-ATPase and acid secretion than omeprazole, and is a m ore rapid inhibitor of proton pumps than omeprazole, lansoprazole, or panto prazole. This probably reflects rabeprazole's faster activation in the pari etal cell canaliculus. In human studies, once-daily doses of 5-40 mg of rab eprazole inhibit gastric acid secretion in a dose-dependent fashion. A once -daily dose of 20 mg has consistently achieved profound decreases in 24-h i ntragastric acidity in single and repeat dosing studies, in healthy volunte ers and patients with either peptic ulcer disease or gastro-oesophageal ref lux disease. Significantly greater decreases in intragastric acidity are ac hieved on day 1 of dosing with rabeprazole 20 mg than with omeprazole 20 mg . As with other proton pump inhibitors, rabeprazole has in vitro antibacter ial activity against Helicobacter pylori, with greater activity against thi s organism than either lansoprazole or omeprazole. In addition to inhibitin g bacterial urease activity, rabeprazole binds to several molecules on H. p ylori. Clinical trials are needed to assess the clinical importance of thes e findings, as well as to assess whether the potential advantages of rabepr azole result in clinical benefit for patients with acid-related diseases.