Acid-inhibitory effects of omeprazole and lansoprazole in Helicobacter pylori-negative healthy subjects.

Background: Omeprazole 20 mg once daily (o.d.) and lansoprazole 30 mg o.d. have similar acid-inhibitory effects in healthy Helicobacter pylori-positive subjects. However, little is known about the acid-inhibitory effects of the o.d. and twice daily (b.d.) doses in H. pylori-negative subjects.

Objective: To compare the decrease in gastric acidity of omeprazole 20 mg (o.d. and b.d.) with lansoprazole 30 mg (o.d. and b.d.) in healthy H. pylori-negative subjects on day 6-7 of dosing.

Methods: A randomized, investigator-blind, crossover study design was used. Intragastric pH was measured continuously with glass electrodes positioned in the gastric corpus. Sixteen H. pylori-negative subjects, whose intragastric acidity fell below pH 4 for 70% of a 24-h baseline period. were entered in the study.

Results: Both dosing regimens of omeprazole and lansoprazole significantly increased median gastric pH and percentages of time above pH 4 during the entire 24-h period, night- and daytime, compared to baseline. There were no significant differences in median gastric pH values or time above pH thresholds 3, 4 and 5 between the o.d. dosing regimens. During the night the percentage of time spent above pH 3 and 4 was significantly higher with omeprazole 20 mg b.d. than with lansoprazole 30 mg b.d.

Conclusions: This comparative study demonstrates that daily doses of omeprazole 20 mg and lansoprazole 30 mg are equally effective in raising intragastric pH in H. pylori-negative subjects on day 6 of dosing. During the night, omeprazole 20 mg b.d. provides superior gastric acid suppression compared to lansoprazole 30 mg b.d.