Effect of nizatidine 300 mg at night and omeprazole 20 mg in the morning on 24-hour intragastric pH and bacterial overgrowth in patients with acute duodenal ulcer.

The study investigated the effect of either nocturnal acid suppression by the H2 antagonist nizatidine 300 mg at night or prolonged acid suppression by the proton- pump inhibitor omeprazole 20 mg in the morning, during four weeks, on intragastric pH profile, occurrence of bacterial growth in gastric fluid and biopsies, and healing rate in 23 patients with an acute duodenal ulcer. The endoscopic healing rate did not differ significantly between the two treatment modalities. The 24-hr acid secretion was significantly more reduced by omeprazole than nizatidine (P < 0.002). After treatment by nizatidine and omeprazole, respectively, median 24-hr intragastric pH increased from 1.5 to 1.8 (P < 0.01) and from 1.5 to 6.1 (P < 0.01), respectively. Nighttime acid inhibition did not differ significantly. The difference in gastric bacterial colonization after either omeprazole or nizatidine did not reach significance. However, median 24-hr pH and the fraction of the day with pH < 3 and pH < 4 were significantly correlated to bacterial colonization of the gastric fluid (P < 0.05).