Transfer of Clarithromycin to Gastric Juice is Enhanced by Omeprazole in Helicobacter pylori -Infected Individuals

Background: The effects of proton-pump inhibitors and Helicobacter pylori infection on the distribution of drugs employed for the eradication of H. pylori are poorly understood. The aim of this study was to investigate the effects of a 7-day oral administration of 20 mg omeprazole on the distribution of clarithromycin in the gastric juice of individuals with H. pylori infection. Methods: Eighteen H. pylori infected dyspeptic male volunteers without endoscopic lesions were enrolled in a study with an open, randomized, two-period crossover design and a 21-day washout period between phases. Plasma and gastric juice concentrations of clarithromycin in subjects with and without omeprazole pretreatment were measured by means of liquid chromatography coupled to tandem mass spectrometry. Results: The maximum concentration of clarithromycin (C max ) and the area under the time-concentration curve from 0 to 2 h (AUC 0-2h ) were significantly higher in gastric juice than in plasma. Omeprazole treatment further augme...