title: Gastric acid suppression is greater during intravenous ranitidine infusion versus bolus injections of famotidine.
abstract: It has been proposed that famotidine may be effective in maintaining intragastric pH > or = 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 > or = 4. More frequent famotidine dosing, or delivery by continuous i.v. infusion, may be required to provide prolonged acid suppression.
authors.affiliation: Division of Gastroenterology, University of California San Diego.
authors.forename: D L
authors.initials: DL
authors.lastname: Hogan
authors.forename: K R
authors.initials: KR
authors.lastname: McQuaid
authors.forename: M A
authors.initials: MA
authors.lastname: Koss
authors.forename: D L
authors.initials: DL
authors.lastname: Crombie
authors.forename: S
authors.initials: S
authors.lastname: Hunter
authors.forename: C
authors.initials: C
authors.lastname: Metz
authors.forename: A R
authors.initials: AR
authors.lastname: Euler
authors.forename: J I
authors.initials: JI
authors.lastname: Isenberg
mesh_terms: D000328:Adult; D015738:Famotidine / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D011899:Ranitidine / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D015738:Famotidine; D011899:Ranitidine