About Rabeprazole Benzimidazole derivative, Proton Pump Inhibitor, Antiulcer. Mechanism of Action of Rabeprazole Rabeprazole sodium is a proton pump inhibitor. It is a prodrug. After administration it diffuses in to the parietal cell of the stomach and accumulates in the secretory canaliculi. In the acidic medium Rabeprazole is converted to sulfenamide. This sulfenamide covalently interacts with sulfhydryl (SH) group in the proton pump (H+ K+ATPase) and inhibits the exchange of extracellular K+ for intracellular H+ ion. Rabeprazole sodium irreversibly inhibits proton pumps activity and decreases gastric acid secretion. Rabeprazole produces fastest acid suppression and helps in mucin synthesis.