Comparison of acid inhibition with standard dosages of proton pump inhibitors in relation to CYP2C19 genotype in Japanese

Abstract

Introduction: The aim of therapeutic regimens using proton pump inhibitors (PPIs) in patients with acid-related diseases is to potently inhibit acid secretion for the full 24 h. However, optimum treatment is still unclear because the pharmacodynamics of PPIs differ among CYP2C19 genotypes and most of the previous studies have had loss of sample power. Methods: Using pH monitoring, we compared acid inhibition at standard dosage of omeprazole (20 mg, 50 times), lansoprazole (30 mg, 68 times), and rabeprazole (10 mg, 65 times) in Helicobacter pylori-negative healthy young Japanese volunteers. Results: Median pH with rabeprazole was 5.4 (3.3-7.5), which was significantly greater than with either omeprazole [4.4 (2.1-7.3)] or lansoprazole [4.8 (3.5-6.4)] (both P∈