Gastric acid suppression is greater during intravenous ranitidine infusion versus bolus injections of famotidine

Abstract

SUMMARY It has been proposed that famotidine may be effective in maintaining intragastric pH ≥ 4 for up to 12 h with a single i.v. 20 mg bolus injection and thereby prevent acute stress‐related mucosal haemorrhage, The present study was designed to compare a ranitidine continuous i.v. infusion (6.25 mg/h) vs. famotidine bolus injection (20 mg every 12 h) on 24‐h intragastric pH and gastric acid secretion. Twenty‐eight healthy volunteers (15 males, 13 females; 20–56 years) participated in two 24‐h treatment periods; each test was in random order separated by 7–10 days. After an overnight fast, subjects were intubated and gastric pH and acid secretion measured hourly. Whereas ranitidine maintained gastric pH above 4 for the entire 24‐h period, mean pH steadily decreased to a nadir of 2.9 and 3.7, respectively, 12 h after each famotidine injection (P < 0.01 vs. ranitidine). Furthermore, gastric acid secretion increased to 4.4 ± 1.2 mmol/h 12 h after famotidine injection compared to 1.1±0.3 mmol/h with ranitidine (P < 0.01). We conclude that ranitidine delivered as a continuous i.v. infusion (6.25 mg/h) is superior to bolus famotidine injections (20 mg) at 12‐h intervals in suppressing gastric acid secretion and maintaining an intragastric pH ≥. 4. More frequent famotidine dosing, or delivery by continuous i.v. infusion, may be required to provide prolonged acid suppression.