Dose ranging study of lansoprazole, a new proton pump inhibitor, in patients with high gastric acid secretion.

The effects of single doses and of 7 days of lansoprazole 10, 20 and 30 mg PO versus placebo on gastric acid secretion have been evaluated in 8 patients with high gastric acid secretion. The double blind crossover period was followed by a simple blind 7 days on placebo to detect any rebound phenomenon. After the first dose lansoprazole did not modify basal acid output (BAO) but it significantly and dose dependently inhibited peak acid output (PAO) and increased the time during which nocturnal intragastric pH was greater than 3. After 7 days of treatment the same significant, dose-dependent suppression of gastric acid was found, but BAO was also blocked. One week after cessation of lansoprazole administration no rebound increase in gastric acid-secretion was observed. The plasma gastrin concentration remained unchanged throughout the study.