title: Intragastric acidity during administration of generic omeprazole or esomeprazole - a randomised, two-way crossover study including CYP2C19 genotyping.
abstract: BACKGROUND
  Generic omeprazole has been approved in many countries for the treatment of acid-related gastrointestinal disorders. However, clinical studies comparing generic to original proton pump inhibitors are limited.
  
  
  OBJECTIVE
  To compare the effect of generic omeprazole 20 mg/day with esomeprazole 20 mg/day on intragastric acidity and to investigate the influence of the CYP2C19 metabolizer status.
  
  
  METHODS
  In this randomised, single-blinded, two-way crossover study, 24 healthy Helicobacter pylori-negative subjects, received generic omeprazole (Omep; Hexal AG, Holzkirchen, Germany) 20 mg once daily or esomeprazole 20 mg once daily for five consecutive days. Twenty-four-hour intragastric pH was recorded on day 5 of each treatment. CYP2C19 status was determined by polymerase chain reaction-restriction fragment length polymorphism.
  
  
  RESULTS
  Over all, there were no statistically significant differences between generic omeprazole and esomeprazole with respect to median intragastric pH (3.5 and 3.9, P = 0.07), the total hours with intragastric pH >4 (10.4 and 11.3, P = 0.29), and during upright (9.6 and 9.1, P = 0.77) or supine (2.2 and 2.2, P = 0.94) position. However, in CYP2C19 rapid metabolizers, esomeprazole was superior to omeprazole, with the percentage of time with intragastric pH >3.0 and pH >3.5 being higher with esomeprazole than with generic omeprazole [Δ = 9% (P = 0.026) and Δ = 8% (P = 0.046), respectively].
  
  
  CONCLUSIONS
  Overall, generic omeprazole 20 mg appears to provide a similar intragastric acid control when compared with esomeprazole 20 mg. However, esomeprazole might be advantageous in subjects with a rapid CYP2C19 metabolizer status.
authors.affiliation: Medical Department I, University Hospital, Dresden, Germany. prof.miehlke@mdz-hamburg.de
authors.forename: S
authors.initials: S
authors.lastname: Miehlke
authors.forename: S
authors.initials: S
authors.lastname: Löbe
authors.forename: A
authors.initials: A
authors.lastname: Madisch
authors.forename: E
authors.initials: E
authors.lastname: Kuhlisch
authors.forename: M
authors.initials: M
authors.lastname: Laass
authors.forename: D
authors.initials: D
authors.lastname: Grossmann
authors.forename: H
authors.initials: H
authors.lastname: Knoth
authors.forename: A
authors.initials: A
authors.lastname: Morgner
authors.forename: J
authors.initials: J
authors.lastname: Labenz
mesh_terms: D000293:Adolescent; D000328:Adult; D000897:Anti-Ulcer Agents / Q000627:therapeutic use*; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics; D018592:Cross-Over Studies; D065731:Cytochrome P-450 CYP2C19; D016568:Drugs, Generic / Q000627:therapeutic use; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D064098:Esomeprazole; D005260:Female; D005744:Gastric Acid; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000188:drug therapy* / Q000235:genetics; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000627:therapeutic use*; D013223:Statistics as Topic; D044465:White People; D055815:Young Adult
chemical_list: D000897:Anti-Ulcer Agents; D016568:Drugs, Generic; D004791:Enzyme Inhibitors; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D009853:Omeprazole; D064098:Esomeprazole