Effect of omeprazole and high doses of ranitidine on gastric acidity and gastroesophageal reflux in patients with moderate-severe esophagitis Thirty to fifty percent of patients with reflux esophagitis fail to heal after treatment with conventional doses of H2-receptor antagonists, whereas omeprazole administration induces more than 90% healing. To investigate the effect of omeprazole and higher-than-presently-recommended doses of H2-blockers, we evaluated gastric acidity and gastroesophageal reflux in 17 patients with severe-moderate esophagitis before and after treatment with 300 mg ranitidine twice daily or 20 mg omeprazole once daily. Three pH-metric studies were performed, in a cross-over design, before and after 8 days of treatment with omeprazole or ranitidine. Both drugs significantly reduced intragastric acidity (p less than 0.001) during both night and day hours. Median hourly 24-h intragastric pH was 1.8 in the basal study, 2.9 after ranitidine, and 3.4 after omeprazole. Intragastric acidity fell from 84.0 mmol/L in the basal study to 14.2 mmol/L (79% inhibition) with ranitidine and 9.3 mmol/L (84% inhibition) with omeprazole. Patients with esophagitis were significantly more exposed to acid than healthy subjects, in both the supine and upright position (p less than 0.01). The time with esophageal pH less than 4 dropped from 23.9% in the basal study to 8.5% with ranitidine and to 7.2% with omeprazole (p less than 0.001). Both drugs significantly reduced esophageal exposure to acid in both the supine and upright positions (p less than 0.001), whereas neither had any effect on esophageal acid clearance. 