Intragastric acidity during administration of generic omeprazole or esomeprazole – a randomised, two‐way crossover study including CYP2C19 genotyping

• Published in: Alimentary pharmacology & therapeutics Vol. 33; no. 4; pp. 471 - 476
• Main Authors: Miehlke, S., Löbe, S., Madisch, A., Kuhlisch, E., Laass, M., Großmann, D., Knoth, H., Morgner, A., Labenz, J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2011; Blackwell; Wiley
• Subjects: Adolescent; Adult; Anti-Ulcer Agents - therapeutic use; Aryl Hydrocarbon Hydroxylases - genetics; Biological and medical sciences; Cross-Over Studies; Cytochrome P-450 CYP2C19; Digestive system; Drugs, Generic - therapeutic use; Enzyme Inhibitors - therapeutic use; Esomeprazole; European Continental Ancestry Group; Female; Gastric Acid; Gastric Acidity Determination; Gastroenterology. Liver. Pancreas. Abdomen; Gastroesophageal Reflux - drug therapy; Gastroesophageal Reflux - genetics; Humans; Hydrogen-Ion Concentration - drug effects; Male; Medical sciences; Middle Aged; Omeprazole - therapeutic use; Pharmacology. Drug treatments; Statistics as Topic; Young Adult; Enzyme; Isozyme; Cytochrome P450; H; Enzyme inhibitor; Genotype; Acidity; Antiulcer agent; Generic drug; K; Crossover study; Proton pump inhibitor; Omeprazole; Intragastric administration; Randomization; Benzimidazole derivatives; Antisecretory agent; Esomeprazole; exchanging ATPase; Hydrolases; Medicine
• ISSN: 0269-2813; 1365-2036; 1365-2036
• DOI: 10.1111/j.1365-2036.2010.04544.x

Summary 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. Aims  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.