title: Acid inhibitory potency of twice a day omeprazole is not affected by eradication of Helicobacter pylori in healthy volunteers.
abstract: OBJECTIVE
  The acid inhibitory effect of proton pump inhibitors is reported to be greater in the presence than in the absence of an H. pylori infection. This study was undertaken to test the hypothesis that the acid inhibitory effect of omeprazole given twice a day is greater in H. pylori infected healthy volunteers than in the same individuals following eradication because of differences in the pharmacodynamics of omeprazole, greater duodenogastric reflux, the effects of ammonia produced by the H. pylori, or lower gastric juice concentrations of selected cytokines, which may inhibit gastric acid secretion.
  
  
  METHODS
  We undertook 24-hour pH-metry in 12 H. pylori-positive healthy volunteers: (1) when on no omeprazole; (2) when on omeprazole 20 mg bid for 8 days; (3) 2 months after eradication of H. pylori and when on no omeprazole; and (4) after eradication of H. pylori and when on omeprazole 20 mg twice a day.
  
  
  RESULTS
  In subjects given omeprazole, eradication of H. pylori reduced pH and percentage pH >or= 3, as well as increasing the area under the H+ concentration-time curve. These differences were not due to alterations in (1) gastric juice concentrations of IL-1alpha, IL-8, IL-13, epidermal growth factor, or bile acids; (2) serum gastrin concentrations; or (3) the pharmacokinetics of omeprazole. There was no change in the difference in the H+ concentration-time curve 'without omeprazole' minus 'with omeprazole', when comparing 'after' versus 'before' eradication of H. pylori.
  
  
  CONCLUSIONS
  Eradication of H. pylori was not associated with an alteration in the acid inhibitory potency when comparing the difference in gastric acidity 'with' versus 'without' omeprazole. When the results were expressed by simply taking into account the acid measurements while on omeprazole before versus after eradication of H. pylori, the acid inhibition with omeprazole was greater in the presence than in the absence of a H. pylori infection. The clinical significance of the small difference is not clear.
authors.affiliation: Nutrition and Metabolism Research Group, University of Alberta, Edmonton, AB, Canada.
authors.forename: Alan B R
authors.initials: AB
authors.lastname: Thomson
authors.forename: Monika
authors.initials: M
authors.lastname: Keelan
authors.forename: Rosann
authors.initials: R
authors.lastname: Lastiwka
authors.forename: Sharon
authors.initials: S
authors.lastname: Appelman-Eszcuck
authors.forename: Lori
authors.initials: L
authors.lastname: Zuk
authors.forename: Laurie
authors.initials: L
authors.lastname: Drozdowski
authors.forename: Anne
authors.initials: A
authors.lastname: Prentice
authors.forename: Paul
authors.initials: P
authors.lastname: Sinclair
mesh_terms: D000328:Adult; D000863:Antacids / Q000008:administration & dosage* / Q000493:pharmacokinetics; D000900:Anti-Bacterial Agents; D001647:Bile Acids and Salts / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination / Q000627:therapeutic use; D005260:Female; D005750:Gastric Juice / Q000276:immunology / Q000378:metabolism; D005755:Gastrins / Q000097:blood; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism*; D016480:Helicobacter pylori; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009853:Omeprazole / Q000008:administration & dosage* / Q000493:pharmacokinetics; D054328:Proton Pump Inhibitors
chemical_list: D000863:Antacids; D000900:Anti-Bacterial Agents; D001647:Bile Acids and Salts; D016207:Cytokines; D005755:Gastrins; D054328:Proton Pump Inhibitors; D009853:Omeprazole