Related Experiment Video
Updated: Jun 23, 2026

Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures
Published on: March 28, 2017
A comparative study of proton-pump inhibitor tests for Chinese reflux patients in relation to the CYP2C19 genotypes
Ping-Huei Tseng1, Yi-Chia Lee, Han-Mo Chiu
1Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
Background:
The proton-pump inhibitor (PPI) test has been proposed as a valuable tool for diagnosing gastroesophageal reflux disease in Western populations.
Goals:
We aim to compare the diagnostic accuracy of the PPI test using rabeprazole and pantoprazole in a Chinese population with a higher prevalence of poor PPI metabolization.
Study:
After diagnostic endoscopy, patients with gastroesophageal reflux disease symptoms were randomly assigned to a 2-week test with rabeprazole (20 mg b.i.d.) or pantoprazole (40 mg b.i.d.). Therapeutic response was assessed with a 5-grade daily record. Genotypes of cytochrome P450 (CYP) 2C19 polymorphism were determined.
Results:
Of the 178 patients who completed the study, 92 (51.7%) had erosive esophagitis and 78 (48.3%) were endoscopy-negative reflux disease. On the basis of 50% reduction of symptoms, there was a nonsignificant difference of diagnostic performances between rabeprazole and pantoprazole. For the CYP2C19 genotypes, 138 (87.3%) were determined to be extensive metabolizers (EMs) and 20 (12.7%) were poor metabolizers (PMs). When comparing the EMs and PMs, the diagnostic specificity in the prediction of erosive esophagitis was higher in the EMs (57.6% vs. 20.0%, P=0.040), as was the accuracy (74.6% vs. 50.0%, P=0.023). There were no differences in the sensitivity, positive predictive value, or negative predictive value.
Conclusions:
CYP2C19 genotypic polymorphism was related to a higher possibility of false-positive results for patients who metabolized PPI poorly. High-dose rabeprazole and pantoprazole showed a similar diagnostic performance.
Related Concept Videos
Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes
Pharmacogenetics of Drug Transporters: P-Glycoprotein and Solute Carrier Transporters
Pharmacogenetics of Drug Metabolism: Overview
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase