Effect of 7-day therapy with different doses of the proton pump inhibitor lansoprazole on the intragastric pH in healthy human subjects.

BACKGROUND

Systematic, randomized, and controlled studies on the effect of low to high doses of the proton pump inhibitor lansoprazole on intragastric acidity and plasma gastrin levels have not previously been performed.

METHODS

We investigated the effect of 7-day therapy with different doses of lansoprazole (15 mg once or twice daily, 30 mg once or twice daily, and 15 mg three times daily) on intragastric acidity and meal-stimulated daytime plasma gastrin levels in 12 healthy Helicobacter pylori-negative human subjects in a randomized, double-blind, placebo-controlled, 6-way crossover study. On days 1, 2, and 7 of the study 24-h intragastric pH-metry and 12-h integrated daytime plasma gastrin determinations were done.

RESULTS

Lansoprazole in a dose regimen of 1 x 30 mg/day, 3 x 15 mg/daily, and 2 x 30 mg/day significantly (P < 0.05) increased the intragastric 24-h median pH on days 1, 2, and 7 of therapy as compared with placebo. Lansoprazole in doses of 1 x 15 mg/day and 2 x 15 mg/day significantly increased the intragastric 24-h median pH on days 2 and 7 but not on day 1 of therapy. Doses of 3 x 15 mg and 2 x 30 mg lansoprazole daily significantly increased the intragastric 24-h median pH on days 2 and 7 of treatment as compared with 1 x 30 mg lansoprazole daily. Except for 1 x 15 mg lansoprazole on day 1 of therapy, all given dose regimens of lansoprazole (15-60 mg/day) significantly (P < 0.05) stimulated the 12-h integrated meal-stimulated daytime plasma gastrin response (pM x min) on days 1, 2, and 7 of therapy as compared with placebo.

CONCLUSION

A dose of 1 x 30 mg/day is nearly as potent as higher dose regimens of lansoprazole. Thus it most likely is the optimum dose for therapy of gastric and duodenal peptic lesions. A dose of 1 x 15 mg lansoprazole daily is a potent inhibitor of gastric acid output and could be a therapeutic dose for prevention of peptic lesions (that is, reflux oesophagitis or ulcers).