Effects of omeprazole in duodenal ulcer patients.

The efficacy of and tolerance to omeprazole, 40 mg/day, was studied in an open-label study in 18 patients with endoscopically verified duodenal ulcers. The effects of the drug on the oxyntic mucosa and pentagastrin-stimulated acid secretion during and after treatment were also studied. Fifteen patients completed the final endoscopy. The ulcers were healed in all after 4 weeks' treatment. Both basal and peak acid output were significantly reduced during omeprazole treatment, whereas 4 weeks after the cessation of treatment neither basal nor peak acid output differed from the pretreatment levels. Fasting serum gastrin levels rose by 56% during treatment but had returned to pretreatment values when tested again 4 weeks after the end of the treatment period. Histological examination of the biopsy specimens taken before and after treatment showed that omeprazole had no significant effect on the volume densities of either parietal or endocrine cells. We conclude that omeprazole is of value in the treatment of duodenal ulcer and that the effects of the drug on acid output and serum gastrin levels are fully reversible.