title: Effect of frequent dosing of an oral proton pump inhibitor on intragastric pH.
abstract: BACKGROUND
  Treatment with a continuous i.v. proton pump inhibitor is presumed to promote clot formation and stability by sustaining intragastric pH > or = 6.
  
  
  OBJECTIVE
  We postulated that very frequent oral dosing of proton pump inhibitors should simulate i.v. infusion and achieve similar pH control.
  
  
  METHODS
  Twenty healthy volunteers were stratified by Helicobacter pylori status (10 positive; 10 negative) and had determination of CYP2C19 status. After an overnight fast, an intragastric pH probe was placed. Subjects received 120 mg of lansoprazole at 8 am and 30 mg every 3 h until 8 pm. Intragastric pH was measured over 24 h, and lansoprazole plasma concentrations were determined at five time points.
  
  
  RESULTS
  Intragastric pH was > or = 6 for 41% (95% CI: 30-53%) of the 15-h period from 8 am-11 pm and 46% (95% CI: 35-56%) of the 24-h period (8-8 am). The mean proportion of patients with pH > or = 6 was not significantly different in H. pylori-positive vs. negative patients. Only 25% of subjects sustained pH > or = 6 for at least 60% of the 15-h period, and 35% had a sustained pH > or = 6 for at least 60% of the 24-h period.
  
  
  CONCLUSIONS
  A dose of 120 mg of oral lansoprazole followed by standard 30 mg doses of lansoprazole every 3 h did not reliably sustain pH at the desired level of 6.
authors.affiliation: Division of Gastrointestinal and Liver Diseases, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Pais
authors.forename: R A
authors.initials: RA
authors.lastname: Nathwani
authors.forename: V
authors.initials: V
authors.lastname: Dhar
authors.forename: A
authors.initials: A
authors.lastname: Nowain
authors.forename: L
authors.initials: L
authors.lastname: Laine
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000328:Adult; D000897:Anti-Ulcer Agents / Q000008:administration & dosage*; D005745:Gastric Acidity Determination; D016480:Helicobacter pylori; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects*; D064747:Lansoprazole; D009853:Omeprazole / Q000008:administration & dosage / Q000031:analogs & derivatives*; D054328:Proton Pump Inhibitors
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D054328:Proton Pump Inhibitors; D064747:Lansoprazole; D009853:Omeprazole