Background: A blood clot in a peptic ulcer is unstable in a low pH environment. The use of omeprazole may prevent rebleeding by elevating intragastric pH in patients with bleeding peptic ulcer after hemostasis has been achieved. Objectives: To assess the influence of using omeprazole and cimetidine on 24-hour intragastric pH and to determine their ability to prevent rebleeding after having achieved initial hemostasis in patients with active bleeding or nonbleeding visible vessels. Methods: One hundred patients with bleeding peptic ulcers who had obtained initial hemostasis were enrolled in this randomized comparative trial. In the cimetidine group (n = 50), a 300-mg intravenous bolus of cimetidine was given, followed by a 1200-mg continuous infusion daily for 3 days. Thereafter, 400 mg of cimetidine was given orally twice daily for 2 months. In the omeprazole group (n = 50), a 40-mg intravenous bolus of omeprazole was given, followed by 160 mg of continuous infusion daily for 3 days. Thereafter, 20 mg of omeprazole was given orally once daily for 2 months. A pH meter was inserted in each patient's fundus under fluoroscopic guidance after the intravenous bolus of cimetidine or omeprazole had been administered. Results: The stigmata of recent hemorrhage before endoscopic therapy in the omeprazole and cimetidine groups were, respectively, spurting (9 vs 12), oozing (4 vs 9), and nonbleeding visible vessel (37 vs 29) (P > .05). The duration of intragastric pH higher than 6.0 was longer in the omeprazole group (mean [+/- SD], 84.4% +/- 22.9%) than that of the cimetidine group (mean [+/- SD], 53.5% +/- 32.3%) (P < .001). Rebleeding occurred in 2 patients (4%) in the omeprazole group and in 12 patients (24%) in the cimetidine group by day 14 after enrollment (P = .004). There was a tendency for patients in the omeprazole group to require less blood transfusion (median, 0 mL; range, 0-2500 mL) than those in the cimetidine group (median, 0 mL; range, 0-5000 mL) (P = .08). The hospital stay and number of operations and mortality rate were similar between both groups. Conclusions: The use of omeprazole is more effective than cimetidine in increasing intragastric pH and reducing rebleeding episodes in patients with bleeding peptic ulcers after successful endoscopic therapy. This suggests that omeprazole should be used routinely after successful endoscopic therapy.
