Clinical Gastroenterology Vol.20 No.8(2-4)

Theme Comparison of PPIs and H2RAs in the Actions and Suitable Use for the Diseases
Title Comparison of Proton Pump Inhibitors and Histamine 2 Receptor Antagonists in Relation to Metabolic Disposition in Liver
Publish Date 2005/07
Author Takahisa Furuta First Department of Medicine, Hamamatsu University School of Medicine
Author Naohito Shirai First Department of Medicine, Hamamatsu University School of Medicine
Author Mitsushige Sugimoto First Department of Medicine, Hamamatsu University School of Medicine
Author Akiko Nakamura First Department of Medicine, Hamamatsu University School of Medicine
[ Summary ] Proton pump inhibitors (PPIs) are mainly metabolized by cytochrome P 450 (CYP) 2C19 in the liver. The pharmacokinetics and pharmacodynamics of PPIs are influenced by genetic differences in CYP2C19. PPIs have the potential to inhibit the activities of CYP enzymes. Drug-drug interactions between PPIs and other drugs have been reported. Most histamine 2 receptor antagonists (H2RA) other than lafutidine, are excreted in the urine. Cimetidine, inhibits CYP enzymes and there have been several reports on drug-drug interactions between cimetidine and other drugs. No clinically undesirable drug-drug interaction via hepatic metabolism have been reported on other H2RAs. The synergistic effects of H2RAs and PPIs are most evident in homozygous extensive metabolizers of CYP2C19. The selections and combinations of H2RAs and PPIs should be determined on the basis of their pharmacological characteristics.
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