Effect of Helicobacter pylori status on intragastric pH during administration of lafutidine or famotidine

There has been no study attempting to compare the effects of lafutidine, a novel H2-receptor antagonist and other H2-receptor antagonists in the same subjects and relating them to H. pylori status. The first aim of this study was to investigate the effect of H. pylori status on intragastric pH in healthy volunteers receiving lafutidine or famotidine. The second aim was to compare the effects of the two antisecretory drugs.

The study was carried out in 11 healthy asymptomatic male volunteers. H. pylori infection was present in 5 subjects. Subjects were first examined by an ambulatory pH monitoring for 24 hours without medication. The second and third 24-hour pH monitoring study was performed on all subjects. Subjects took 10 mg lafutidine or 20mg famotidine at 9:00 and 21:00.

During administration of lafutidine or famotidine, the percentage of period holding intragastric pH >4 was not significantly different between the H. pylori-negative and -positive subjects. Among the H. pylori negative subjects, the percentage of daytime period holding intragastric pH >4 was significantly greater with lafutidine than with famotidine (p < 0.05).

The effect of lafutidine to increase intragastric pH was not affected by the H. pylori status. Among H. pylori-negative subjects, lafutidine was proven to be more effective than famotidine for acid control during the daytime in Japanese healthy volunteers.