Rabeprazole produces rapid, potent, and long-acting inhibition of gastric acid secretion in subjects with Helicobacter pylori infection

Aim: To compare acid inhibiting activity and duration of action of differen t doses of rabeprazole, a substituted benzimidazole characterized as a high ly potent and irreversible H+, K+-ATPase inhibitor, administered for 7 days to subjects infected with Helicobacter pylori. Methods: A total of 38 subjects (mean age 39.3 years) were enrolled in a si ngle-centre, double-blind, randomized, crossover study. All subjects were c onfirmed positive for H. pylori by C-14 urea breath test and ELISA serologi es. Subjects were divided into two groups of 19 to receive two doses of rab eprazole, either 5 and 20 mg or 10 and 40 mg, and placebo, given in random order daily in the morning for 7 days. Peptone-stimulated acid, pH, and gas trin measurements were made for 24 h after the 1st dose and for 48 h after the 7th dose. Results: Peptone-stimulated acid secretion rates were decreased from 12.5 t o 6.7, 4.0, 1.5, and 0.26 h after initial 5, 10, 20, and 40 mg doses, respe ctively; to 7.3, 4.3, 2.1, and 1.2 mmol/h 23 h after the initial dose; and to 2.4, 2.6, 0.6, and 0.8 mmol/h 23 h after the 7th dose. After 48 h, stimu lated acid secretion had recovered less than 40% for all treatment groups c ompared to placebo. Median intragastric pH also increased from 2.0 with pla cebo to 4.9, 6.2, 6.6 and 6.9 during the 24-h period after the 7th dose of 5, 10, 20, and 40 mg. The 20 mg dose of rabeprazole produced equivalent aci d inhibition to the 40 mg dose with less increase in plasma gastrin. Conclusion: Rabeprazole in doses from 5 to 40 mg was a highly effective inh ibitor of gastric acid secretion in subjects infected with H. pylori. The i nhibition was rapid, dose-related, and long-acting, with less than 50% reco very of acid by 48 h after the 7th dose. The optimal acid inhibitory dose i n these subjects appeared to be 20 mg daily, however 5 mg and 10 mg doses p roduced potent inhibition of gastric acid secretion.