title: Rapid effect of lansoprazole on intragastric pH: a crossover comparison with omeprazole.
abstract: BACKGROUND
  The time to onset of acid inhibition is considered an important factor when treating patients with reflux symptoms. This study was therefore designed to investigate the effect of 30 mg lansoprazole and 20 mg omeprazole on gastric pH after single-dose administration.
  
  
  METHODS
  The study was of a randomized, open-label, single-dose and two-way crossover design with a washout period of at least 7 days in between. Fifteen healthy adult male and female subjects were included. The subjects were intubated with a pH catheter. Intragastric pH was measured every 4th sec for 10 min before and during 8 h after drug administration. Blood samples, for determination of plasma concentrations of lansoprazole and omeprazole, were obtained on 10 occasions during 6 h after drug administration. The area under the curve (AUC), the elimination halflife (t1/2), and the peak concentration (Cmax) of the two drugs were calculated.
  
  
  RESULTS
  All subjects completed the study without major complications. The mean pH (0-8 h) after drug administration was 2.9 for lansoprazole and 2.0 for omeprazole (P = 0.0058). A pH of more than 4 was reached for the first time after 130 min with lansoprazole and after 250 min with omeprazole. AUC was 4919 +/- 2526 nmol/l x h for lansoprazole and 1352 +/- 1120 nmol/l x h for omeprazole.
  
  
  CONCLUSIONS
  Single-dose administration of 30 mg lansoprazole is followed by a rapid absorption of the drug and hence a more efficient acid suppression than after single-dose administration of 20 mg omeprazole in healthy volunteers.
authors.affiliation: Wyeth Lederle Nordiska, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Thoring
authors.forename: H
authors.initials: H
authors.lastname: Hedenström
authors.forename: L S
authors.initials: LS
authors.lastname: Eriksson
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000328:Adult; D000863:Antacids / Q000097:blood / Q000494:pharmacology*; D000897:Anti-Ulcer Agents / Q000097:blood / Q000494:pharmacology*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D005745:Gastric Acidity Determination; D006801:Humans; D064747:Lansoprazole; D008297:Male; D009853:Omeprazole / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000863:Antacids; D000897:Anti-Ulcer Agents; D064747:Lansoprazole; D009853:Omeprazole