Metabolism Of Proton Pump Inhibitors Research Articles

Effect of MDR1 C3435T and CYP2C19 genetic polymorphisms on the outcome of Helicobacter pylori eradication treatment in children with gastritis and peptic ulcer, Vietnam

BackgroundHelicobacter pylori eradication therapy based on antimicrobial susceptibility in Vietnamese children currently get low efficiency. There are causes of treatment failure, among host genetic factors namely MDR1 C3435T and CYP2C19 affect the absorption and metabolism of proton pump inhibitors - a crucial component of eradication therapy. The study aimed to investigate the effect of MDR1 C3435T and CYP2C19 genetic polymorphisms on the cure rate.Methods207 pediatric patients with gastritis and peptic ulcer infecting Helicobacter pylori completed the eradication therapy based on antimicrobial susceptibility with proton pump inhibitor esomeprazole. Eradication efficacy was assessed after at least 4 weeks by the urease breath test. MDR1 C3435T genetic polymorphism and CYP2C19 genotype were determined using a sequencing method based on Sanger’s principle.ResultsAmong 207 children recruited in this study, the ratio of CYP2C19 EM, IM, and PM phenotypes was 40.1%, 46.4%, and 16.9%, respectively. The patient with MDR1 3435 C/C polymorphism accounted for 43.0%, MDR1 3435 C/T was 40.1%, and MDR1 3435T/T was 16.9%. The cure rate of Helicobacter pylori infection in patients with CYP2C19 EM genotype was 78.3%; 83.3% of those with the IM genotype, and PM genotype was 96,4% (p = 0.07). Successful eradication rates for Helicobacter pylori were 85.4%, 86.7%, and 68.6% in patients with the MDR1 3435 C/C, C/T, and T/T, respectively (p = 0.02). Multiple logistic regression analysis found that MDR1 C3435T genetic polymorphisms of patients were significant independent risk factors for treatment failure, and CYP2C19 genotype did not affect Helicobacter pylori eradication.ConclusionsThe Helicobacter pylori eradication rates by regimens based on antibiotic susceptibility and esomeprazole were not significantly different between the CYP2C19 phenotypes. The MDR1 C3435T polymorphism is one of the factors impacting Helicobacter pylori eradication results in children.

Implementing pharmacogenetic testing to optimize proton-pump inhibitors use among Indian population based on CPIC-CYP2C19-PPI dosing guidelines: The need of the hour

Abstract Proton-pump inhibitors (PPIs) are widely prescribed to decrease stomach acid and treat various acid-related Gastrointestinal tract (GIT) diseases. However, genetic variations, particularly in the CYP2C19 gene, affect PPIs metabolism and efficacy. Variants in CYP2C19 can result in different rates of PPI metabolism, influencing their effectiveness. Personalized medicine strategies, such as genotyping for CYP2C19, have the potential to enhance the effectiveness of PPI therapy and patient safety. This review aims to describe the relevance of CYP2C19 genetic profiling in the indian population, including normal function (e.g. CYP2C19*1, *11, *13, *15, *18, *28, and 38), decreased function (e.g., CYP2C19*9, *10, *16, *19, *25, and 26), loss of function (e.g., CYP2C19*2, *3, *4, *5, *6, *7, *8, *22, *24, *35, *36, and *37), and increased function (e.g., CYP2C19*17) variants. This review also examines the clinical pharmacogenomics implementation consortium (CPIC)-CYP2C19-PPI guidelines to highlight the importance of pharmacogenomics (PGx)-informed personalized PPI therapy for gastroesophageal reflux disease and peptic ulcer disease treatment. On average, each person in India possesses eight pharmacogenetic (PGx) variants that can be clinically significant, underscoring the need for preemptive testing. Implementing CYP2C19 genetic testing in India requires expanding laboratory capacity, increasing accessibility in primary care, increasing public awareness, collaboration between pharmacovigilance and PGx programs, investing in advanced sequencing technologies, data management systems, and integration with electronic health records and clinical decision support systems. Addressing challenges such as genetic diversity, socioeconomic factors, health-care access issues, and shortage of trained professionals is essential for implementation. Due to the lack of definitive country-specific policies and PGx guidelines from Indian drug regulatory agencies, guidelines from international consortia such as the Clinical Pharmacogenetics Implementation Consortium and drug labeling offer crucial foundational evidence. This evidence can be used to enhance patient outcomes and ensure the safe and effective use of PPIs in India.

Influence of novel CYP2C-haplotype on proton pump inhibitor pharmacokinetics in children.

In this brief report, we provide an analysis of the influence of a novel CYP2C haplotype (CYP2C:TG) on proton pump inhibitor (PPI) pharmacokinetics (PK) in children. The CYP2C:TG haplotype has been proposed to be associated with increased CYP2C19 activity. We sought to determine if this CYP2C:TG haplotype resulted in similar alterations in metabolism for proton pump inhibitors, which are primarily metabolized by CYP2C19. In a cohort of 41 children aged 6-21 participating in a PPI pharmacokinetic study, effects of the CYP2C:TG allele were assessed by fitting two linear regression models for each of the six PK outcomes assessed, the second of which accounted for the presence of the CYP2C:TG allele. The difference in R2 values between the two models was computed to quantify the variability in the outcome that could be accounted for by the CYP2C:TG allele after adjustment for the CYP2C19 genotype. We found the CYP2C:TG haplotype to have no measurable additive impact on CYP2C19-mediated metabolism of PPIs invivo in older children and adolescents. The findings of this study do not support the clinical utility of routine testing for the CYP2C:TG haplotype to guide PPI dose adjustments in children.

Impact of CYP2C19 metabolizer status on esophageal mucosal inflammation, acid exposure, and motility among patients on chronic proton-pump inhibitor therapy with refractory symptoms of gastroesophageal reflux disease.

The extent of disease severity remains unclear among CYP2C19 rapid and ultra-rapid metabolizers with refractory symptoms of gastroesophageal reflux disease (GERD) on chronic proton-pump inhibitors (PPIs). To determine the impact of CYP2C19 metabolizer status in relation to chronic PPI therapy with a focus on the extent of esophageal inflammation, acid exposure, and motor function. This retrospective study included 54 patients with refractory GERD symptoms who underwent CYP2C19 genotyping for PPI metabolism, esophagogastroduodenoscopy, ambulatory pH study, and high-resolution esophageal manometry. Patients were divided into three groups: normal metabolizer (NM) group, intermediate metabolizer/poor metabolizer (IM/PM) group, and rapid metabolizer/ultra-rapid metabolizer (RM/UM) group. The Chi-square test was used to analyze categorical variables, and one-way ANOVA for comparing means. Rapid metabolizer/ultra-rapid metabolizer (RM/UM) group more frequently had either Los Angeles grade C or D GERD (7/19, 36.8% vs 1/21, 4.8%, P = 0.011) and metaplasia of the esophagus (9/19, 47.4% vs 2/21, 9.5%, P = 0.007) when compared to the NM group. RM/UM group were more frequently offered dilatation for nonobstructive dysphagia (8/19, 42.1% vs 3/21, 14.3%, P = 0.049) and more exhibited a hypotensive lower esophageal sphincter (LES) resting pressure compared to the NM group (10/19, 52.6% vs 4/21, 19%, P = 0.026). All three groups exhibited comparable DeMeester scores when PPIs were discontinued 72 hours before the ambulatory pH study. CYP2C19 RMs and UMs on chronic PPI with refractory GERD symptoms exhibited greater esophageal mucosal inflammation, as observed both endoscopically and histologically, and more were found to have hypotensive LES resting pressures and more were offered esophageal dilatation.

Development and validation of next-generation sequencing panel for personalized Helicobacter pylori eradication treatment targeting multiple species.

The decreasing Helicobacter pylori eradication rate is primarily attributed to antibiotic resistance, and further exacerbated by uniform drug administration disregarding a host's metabolic capability. Consequently, applying personalized treatment based on antibiotic resistance-associated variants and the host's metabolic phenotype can potentially increase the eradication rate. A custom next-generation sequencing panel for personalized H. pylori eradication treatment (NGS-PHET) was designed which targeted the regions for amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin-resistance in H. pylori and human proton-pump inhibitor (PPI) metabolism. The libraries were constructed following customized methods and sequenced simultaneously. The customized framework criteria, grounded in previously reported antibiotic resistance associated variants and the host's PPI metabolism, was applied to the NGS-PHET results and suggested a personalized treatment for each subject, which was validated through each subject's actual eradication outcome. Both previously reported and novel variants were identified from H. pylori sequencing results. Concurrently, five CYP2C19 homozygous extensive metabolizers and three CYP3A4 intermediate metabolizers were identified. Among the total of 12 subjects, clarithromycin triple therapy was suggested for five subjects, bismuth quadruple therapy was suggested for six subjects, and rifabutin triple therapy was suggested for one subject by following the customized framework criteria. The treatment suggestion for nine of the 12 subjects was consistent with the treatment that each subject achieved eradication with. Applying the methodology using the NGS-PHET and customized framework helps to perform eradication treatment quickly and effectively in most patients with antibiotic-resistant H. pylori strains, and is also useful in research to find novel antibiotic-resistance candidates.

CYP2C19 genotypes and osteoporotic fractures in long-term users of proton pump inhibitors: A hospital-based study.

Proton pump inhibitors (PPIs) are commonly prescribed medications. The existing data suggest that individuals at a high risk of fractures have been exposed to high doses of PPIs for prolonged durations. CYP2C19 plays a pivotal role in metabolism of PPIs and thereby influences their pharmacokinetic profile. Hence, we hypothesize that CYP2C19 genotypes may be associated with fragility fracture among PPIs users due to PPI exposure. This study aimed to investigate the association between CYP2C19 genotypes, bone mineral density (BMD), and osteoporotic fracture in a hospital-based population. This retrospective cohort study enrolled patients who were prescribed long-term PPIs at Taichung Veterans General Hospital using data extracted from the Taiwan Precision Medicine Initiative between January 2010 and April 2021. Associations between CYP2C19 phenotypes, comorbidities, and fractures in PPI users were analyzed. We enrolled 1518 long-term PPI users; 571 (38%), 727 (48%), and 220 (14%) CYP2C19 normal metabolizers (NMs), intermediate metabolizers (IMs), and poor metabolizers (PMs), respectively. Among them, 49 (3.2%) patients developed fractures within the 1-year follow-up period; 20 (3.5%) fractures in NMs, 24 (3.3%) in IMs, and 5 (2.3%) in PMs, respectively. No significant difference was observed among CYP2C19 genotypes and fracture. Additionally, BMD measurements during the 1-year follow-up period were made available among 75 participants. No significant difference in BMD between CYP2C19 PMs and non-PMs was found. This real-world, hospital-based study concludes that CYP2C19 PMs/IMs are not associated with an increased risk for fractures or reduced BMD in individuals on long-term PPI therapy.

A Pharmacogenetics-Based Approach to Managing Gastroesophageal Reflux Disease: Current Perspectives and Future Steps.

Proton pump inhibitors (PPIs) are commonly used medications to treat acid-related conditions, including gastro-esophageal reflux disease (GERD). Gastroenterology guidelines mention the importance of CYP2C19 in PPI metabolism and the influence of CYP2C19 genetic variations on variable responses to PPIs, but do not currently recommend the genotyping of CYP2C19 prior to prescribing PPIs. There are strong data to support the influence of CYP2C19 genetic variations on the pharmacokinetics of PPIs and clinical outcomes. Existing pharmacogenetic guideline recommendations for dose increases focus on H. pylori and erosive esophagitis indications, but PPIs are also the main therapy for treating GERD. Recent data suggest GERD patients being treated with a PPI may also benefit from genotype-guided dosing. We summarize the literature supporting this contention and highlight future directions for improved management of patients with GERD through precision medicine approaches.

Review on Concomitant Use of Proton Pump Inhibitors [PPI] with Antiplatelet Agents

Clopidogrel and proton pump inhibitors (PPI) are the two drugs which are commonly used in clinical settings. clopidogrel is an anti-platelet drug used for cardiovascular and cerebrovascular disease. The main drawback of long-term use of antiplatelet therapy is gastrointestinal bleeding so that the patients with antiplatelet drug is prescribed with proton pump inhibitors as a prophylactic measure. Many studies suggest that proton pump inhibitors can reduce the antiplatelet effect of clopidogrel by inhibiting the enzyme CYP450.clopidogrel is a prodrug which is converted to active drug mainly by CYP2C19 in the liver. The same enzyme is responsible for the metabolism of proton pump inhibitors. Hence there is a possibility of interaction between clopidogrel and proton pump inhibitors. As a result, there is a chance of increasing cardiovascular events in patient taking proton pump inhibitors along with clopidogrel. Keywords: [proton pump inhibitors, clopidogrel, gastrointestinal bleeding, prodrug, CYP450 enzyme, interaction]

Effect of major CYP2C19 genetic polymorphisms on Helicobacter pylori eradication based on different treatment regimens.

Helicobacter pylori (H. pylori) infection is a global issue. Its eradication in affected individuals is important to prevent several further complications that may occur if left untreated. Proton pump inhibitors (PPIs) serve an important role in the eradication regimens of H. pylori. PPIs are metabolized primarily through the CYP2C19 enzyme in the liver. Inter-individual variation in the response to eradication treatment may partly be due to variations in the metabolism of PPIs. The aim of this study was to determine whether there was any association between CYP2C19 genetic polymorphisms and the response to eradication therapy amongst Jordanians infected with H. pylori receiving lansoprazole-based regimens. The present study was approved by the Institutional Review Board of The University of Jordan Hospital. A total of 141 patients infected with H. pylori were genotyped for the polymorphisms CYP2C19*2 and CYP2C19*17 using the PCR-restriction fragment length polymorphism assay method. Patients received lansoprazole-based triple or sequential therapy. The assessment of eradication was performed using either a H. pylori stool antigen test or from feedback from patients regarding their improvement. Eradication rates were 84.6% and 64.5% in the intermediate-metabolizer and extensive-metabolizer group, respectively. This difference was not statistically significant. Moreover, no significant association was found between the carriers of the CYP2C19*17 polymorphism and the response to eradication therapy. These findings suggest that there was no significant association between the CYP2C19 genotype and the response to eradication therapy amongst Jordanians infected with H. pylori.

How We Approach Difficult to Eradicate Helicobacter pylori

How We Approach Difficult to Eradicate Helicobacter pylori

Effects of CYP2C19 Polymorphism on Metabolism and Effectiveness of Proton Pump Inhibitors: A Review of Clinical and Laboratory Studies

Introduction: Establishing the reasons for the decrease in the effectiveness of anti-Helicobacter pylori therapy and proton pump inhibitors in the treatment of acid-dependent diseases is an urgent task due to high prevalence of these disorders undermining population health. Our objective was to conduct a literature review to assess the influence of the genetic polymorphism of cytochrome P-450 CYP2C19 on the eradication rate of Helicobacter pylori and the metabolism of proton pump inhibitors, to evaluate the effectiveness of their use, and to determine possible ways of overcoming refractoriness to these drugs in the clinic. Materials and methods: We analyzed published studies found in domestic (eLibrary, CyberLeninka.ru) and international (PubMed, Cochrane Library) databases. Results: We revealed a genetic polymorphism CYP2C19 of cytochrome P-450, according to which different types of drug metabolism were identified: fast, intermediate, slow, and ultrafast. The relationship of this polymorphism with biotransformation of proton pump inhibitors was then analyzed. In Russia, the predominance of fast and intermediate metabolism in individuals of the Caucasian race decreases the efficacy of acid-suppressive therapy and the Helicobacter pylori eradication rate. Correction of the daily dose and frequency of drug administration are necessary to increase the antisecretory effect of proton pump inhibitors. Discussion: The dependence of proton pump inhibitor biotransformation on the CYP2C19 polymorphism determines the differences between patients with different types of metabolism in the effectiveness of these drugs, the success of anti-Helicobacter pylori treatment, and clinical outcomes. Pharmacogenetic testing is useful for predicting the response to proton pump inhibitors, the likelihood of developing adverse events, and the possibility of personalized prescriptions in patients with acid-related diseases. Conclusion: Genetic testing of cytochrome CYP2C19 helps optimize the use of proton pump inhibitors, overcome refractoriness, and improve the quality of treatment of acid-dependent diseases and the overall Helicobacter pylori eradication rate.

Effect of proton pump inhibitors on voriconazole concentrations in Chinese patients with malignant hematological diseases.

To evaluate the influence of three proton pump inhibitors (PPIs) on plasma voriconazole (VOR) concentrations and characterize potential drug-drug interactions (DDIs) between VOR and three PPIs (omeprazole, lansoprazole, and pantoprazole) in Chinese patients with malignant hematological diseases. A simple and reliable 2D-HPLC with internal quality control method was used to ensure accurate concentration measurements. A total of 194 patients in this retrospective study were divided into control (N = 59), omeprazole (OME, N = 57), lansoprazole (LAN, N = 26), and pantoprazole (PAN, N = 52) groups for comparison of plasma VOR trough concentrations. To further validate our retrospective analysis of clinical data, we used molecular docking simulation to analyze the binding affinity of PPIs to the cytochrome P450 2C19 (CYP2C19) and cytochrome P450 3A4 (CYP3A4) enzymes that areintegral to the metabolism of PPIs and VOR. Our findings indicated that VOR trough concentrations were significantly higher in patient on PPIs compared with those who were not (P = 0.012). Patients on LAN (P < 0.01) or OME (P < 0.05) had significantly elevated VOR concentrations compared with the control group, whereas those on PAN did not. Although VOR trough concentrations were not significantly elevated with PAN, more patients in the PAN group reached therapeutic VOR concentrations than in any other group. In conclusion, our retrospective data analysis and molecular docking simulations results indicate that LAN and OME interact with VOR via CYP2C19 and CYP3A4to increase VOR plasma concentrations. This study helps with selection of PPIs in Chinese patients with malignant hematological cancer administered VOR.

Mechanism of Reductive Metabolism and Chiral Inversion of Proton Pump Inhibitors.

Racemic proton pump inhibitors (PPIs) have been developed into pure enantiomers given superior pharmacokinetic profiles. However, after doses of single enantiomer PPIs, different degrees of chiral inversion were observed. We investigated the relationship between chiral inversion and reductive metabolism of PPIs, as well as the mechanism of reductive metabolism. In liver microsomes and Sprague-Dawley rats, PPI thioethers were stereoselectively oxidized to (R)- and (S)-PPIs, indicating that thioethers could be the intermediates of chiral inversion. By comparing the area under the plasma concentration-time curve ratios of thioether to rabeprazole under different routes of administration and blood sampling site, it was determined that thioether was mainly formed in the liver rather than the intestine. The formation rate of PPI thioethers in liver subcellular fractions was significantly higher than that in buffers. Sulfhydryl-blocking agents, such as N-ethylmaleimide, menadione, and ethacrynic acid, inhibited the reductive metabolism of PPIs in vitro, and their corresponding glutathione conjugates were observed. Similar amounts of thioethers were formed in glutathione solutions as in liver subcellular fractions, indicating that biologic reducing agents, instead of reductases, accelerated the reductive metabolism of PPIs. The reduction rates in glutathione solutions were ordered as follows: rabeprazole > omeprazole > lansoprazole > pantoprazole, which was consistent with the natural bond orbital charges of sulfur atoms in these compounds. In conclusion, PPIs were transformed into thioethers by biologic reducing agents in liver, and thioethers continued to be oxidized to two enantiomers, leading to chiral inversion. Furthermore, inhibiting oxidative metabolism of PPIs enhanced reductive metabolism and chiral inversion.

Genotype tailored treatment of mild symptomatic acid reflux in children with uncontrolled asthma (GenARA): Rationale and methods

Asthma causes enormous suffering and cost for children in the US and around the world [1–3]. Co-morbid gastroesophageal reflux disease (GERD) makes asthma management more difficult due to increased symptoms. Proton pump inhibitor (PPI) drugs are effective at improving to GERD symptoms, however they have demonstrated only modest and variable effects on asthma control in the setting of co-morbid GERD. Importantly, PPI metabolism and efficacy depend on CYP2C19 genotype. The Genotype Tailored Treatment of Symptomatic Acid Reflux in Children with Uncontrolled Asthma (GenARA) study is a randomized, double-blind, placebo-controlled trial to determine if genotype-tailored PPI dosing improves asthma symptoms among children with inadequately controlled asthma and GERD symptoms. This study has an innovative design to both assess the efficacy of genotype-tailored PPI dosing and perform pharmacokinetic modeling of the oral PPI Lansoprazole. Children ages 6–17 years old with clinician-diagnosed asthma and mild GERD symptoms will submit a saliva sample for CYP2C19 genotyping. Participants will undergo a two-step randomization to: (1) genotype-tailored versus conventional dosing of open-label oral lansoprazole for pharmacokinetic modeling, and (2) genotype-tailored lansoprazole daily versus placebo for 24 weeks to determine the effect of genotype-tailored PPI dosing on asthma control. Measures of asthma control, spirometry, and nasal washes during acute illnesses will be collected at 8-week intervals throughout the study. GenARA will better define the effects of CYP2C19 genotype on the dose response of lansoprazole in children and adolescents and assess if a novel dosing regimen improves GERD and asthma control.

CYP2C19 polymorphism in relation to the pharmacotherapy optimization of commonly used drugs.

Purpose: The CYP2C19 isoenzyme plays an important role in the efficacy and safe use of many drugs. The aim of this review is to demonstrate how CYP2C19 mutations influence everyday patient treatment, leading to adverse drug reactions or therapy failure in many common diseases. Methods: A PubMed literature search was performed on clinical publications evaluating the impact of CYP2C19 on pharmacotherapy outcome. Main fields of medicine with strong outcome dependency on the CYP2C19 genotype were selected. We also focused on clinical recommendations for the use of drugs referring to CYP2C19 polymorphism. Results: The fields of medicine where clinical outcome particularly depends on CYP2C19 polymorphism are gastroenterology, cardiology, psychiatry, mycology and oncology. CYP2C19 is involved in proton pump inhibitors metabolism, thus it can influence reflux therapy, ulcer prevention and Helicobacter pylori eradication treatment. The CYP2C19 enzyme plays also a vital role in the two bioactivation steps of clopidogrel leading to lower (CYP2C19*17 carriers) or higher (CYP2C19*2 carriers) risk of major adverse cardiovascular events. It affects the antidepressant treatment and methadone replacement therapy as well as voriconazole prophylaxis. The presence of a *2 allele is associated with longer relapse-free time or better survival, and the *17 allele with more favorable outcomes in breast cancer patients treated with tamoxifen. Conclusions: Knowledge of the CYP2C19 polymorphism could positively affect individual treatment and lead to better patient outcomes in many cases. The introduction of pharmacogenetic testing into medical practice would be a good way to minimize negative outcomes of therapy, and to reduce unnecessary medical costs.

ARE THE PERSISTENT SYMPTOMS TO PROTON PUMP INHIBITOR THERAPY DUE TO REFRACTORY GASTROESOPHAGEAL REFLUX DISEASE OR TO OTHER DISORDERS?

Gastroesophageal reflux disease (GERD) is a clinical condition that develops when the reflux of stomach contents causes troublesome symptoms and/or complications. Transient lower esophageal sphincter relaxation is the main pathophysiological mechanism of GERD. Symptoms and complications can be related to the reflux of gastric contents into the esophagus, oral cavity, larynx and/or the lung. Symptoms and other possible manifestations of GERD are heartburn, regurgitation, dysphagia, non-cardiac chest pain, chronic cough, chronic laryngitis, asthma and dental erosions. The proton pump inhibitor (PPI) is the first-choice drug and the most commonly medication used for the treatment of GERD. The most widespread definition of Refractory GERD is the clinical condition that presents symptoms with partial or absent response to twice-daily PPI therapy. Persistence of symptoms occurs in 25% to 42% of patients who use PPI once-daily and in 10% to 20% who use PPI twice-daily. The objective is to describe a review of the current literature, highlighting the causes, diagnostic aspects and therapeutic approach of the cases with suspected reflux symptoms and unresponsive to PPI. Initially, the management of PPI refractoriness consists in correcting low adherence to PPI therapy, adjusting the PPI dosage and emphasizing the recommendations on lifestyle modification change, avoiding food and activities that trigger symptoms. PPI decreases the number of episodes of acid reflux; however, the number of "non-acid" reflux increases and the patient continues to have reflux despite PPI. In this way, it is possible to greatly reduce greatly the occurrence of symptoms, especially those dependent on the acidity of the refluxed material. Response to PPI therapy can be evaluated through clinical, endoscopic, and reflux monitoring parameters. In the persistence of the symptoms and/or complications, other causes of Refractory GERD should be suspected. Then, diagnostic investigation must be initiated, which is supported by clinical parameters and complementary exams such as upper digestive endoscopy, esophageal manometry and ambulatory reflux monitoring (esophageal pH monitoring or esophageal impedance-pH monitoring). Causes of refractoriness to PPI therapy may be due to the true Refractory GERD, or even to other non-reflux diseases, which can generate symptoms similar to GERD. There are several causes contributing to PPI refractoriness, such as inappropriate use of the drug (lack of patient adherence to PPI therapy, inadequate dosage of PPI), residual acid reflux due to inadequate acid suppression, nocturnal acid escape, "non-acid" reflux, rapid metabolism of PPI, slow gastric emptying, and misdiagnosis of GERD. This is a common cause of failure of the clinical treatment and, in this case, the problem is not the treatment but the diagnosis. Causes of misdiagnosis of GERD are functional heartburn, achalasia, megaesophagus, eosinophilic esophagitis, other types of esophagitis, and other causes. The diagnosis and treatment are specific to each of these causes of refractoriness to clinical therapy with PPI.

Evaluating the Effect of Six Proton Pump Inhibitors on the Antiplatelet Effects of Clopidogrel

Cytochrome P450 (CYP) enzymes are responsible for the conversion of clopidogrel into its active metabolite and the metabolism of proton pump inhibitors (PPIs), which may also inhibit CYP enzymes. A current Food and Drug Administration advisory suggests avoiding esomeprazole and omeprazole while taking clopidogrel because of concerns that PPIs may compromise clopidogrel's antiplatelet effects. The objective of the present study was to examine the robustness of this interaction using a well-controlled study design in a population of participants free of confounders. Twenty-eight healthy male participants, with a mean age 24.2 ± 3.2, were randomized to an incomplete crossover design schedule. Participants underwent platelet aggregation testing after clopidogrel alone, while on clopidogrel in combination with 1 of 3 PPIs (40 mg of pantoprazole, 20 mg of omeprazole, 20 mg of rabeprazole, 40 mg of esomeprazole, 30 mg of lansoprazole, or 30 mg of dexlansoprazole), and during 1 week of clopidogrel-only washout periods. The median platelet aggregation to adenosine diphosphate during a drug-free baseline was 10Ω (2.5 interquartile range) of impedance and decreased to 0Ω on clopidogrel alone. Aggregation did not significantly change with concomitant use of PPIs and clopidogrel. These data do not demonstrate a significant interaction between common individual PPIs and clopidogrel in healthy volunteers who respond to clopidogrel alone. This adds data to a growing body of evidence indicating that the addition of a PPI may have a weak effect on clopidogrel's antiplatelet properties, and may only be relevant in specific clinical circumstances.

A review of medical therapy for proton pump inhibitor nonresponsive gastroesophageal reflux disease.

Up to 40% of patients report persistent gastroesophageal reflux disease (GERD) symptoms despite proton pump inhibitor (PPI) therapy. This review outlines the evidence for medical therapy for PPI nonresponsive GERD. A literature search for GERD therapies from 2005 to 2015 in PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews identified 2928 unique citations. Of those, 40 unique articles specific to the impact of PPI metabolizer genotype on PPI response and the use adjunctive medical therapies were identified. Thirteen articles reported impacts on CYP genotypes on PPI metabolism demonstrating lower endoscopic healing rates in extensive metabolizers; however, outcomes across genotypes were more uniform with more CYP independent PPIs rabeprazole and esomeprazole. Twenty-seven publications on 11 adjunctive medications showed mixed results for adjunctive therapies including nocturnal histamine-2 receptor antagonists, promotility agents, transient lower esophageal sphincter relaxation inhibitors, and mucosal protective agents. Utilizing PPI metabolizer genotype or switching to a CYP2C19 independent PPI is a simple and conservative measure that may be useful in the setting of incomplete acid suppression. The use of adjunctive medications can be considered particularly when the physiologic mechanism for PPI nonresponse is suspected. Future studies using adjunctive medications with improved study design and patient enrollment are needed to better delineate medical management options before proceeding to antireflux interventions.

The Frequency of Cyp2c19 Genetic Polymorphisms In Russian Patients With Peptic Ulcer Treated With Proton Pump Inhibitors

The Frequency oF cyP2c19 GeneTic PolymorPhisms in russiAn PATienTs WiTh PePTic ulcer TreATed WiTh ProTon PumP inhibiTors N.P. Denisenko; D.A. Sychev; Zh.M. Sizova; A.V. Grachev; and K.A. Velikolug Russian Medical Academy of Post-Graduate Education, Moscow, Russia; I.M. Sechenov First Moscow State Medical University, Moscow, Russia; SM-Clinic, Moscow, Russia; and Out-patient department No. 51 branch 3, Moscow, Russia Introduction: Proton pump inhibitors, which are widely used as acid-inhibitory agents for the treatment of peptic ulcer, are mainly metabolized by 2C19 isoenzyme of cytochrome P450 (CYP2C19). CYP2C19 has genetic polymorphisms, associated with extensive, poor, intermediate or ultrarapid metabolism of proton pump inhibitors. Genetic polymorphism of CYP2C19 could be of clinical concern in the treatment of peptic ulcer with proton pump inhibitors. The aim of the study – to investigate the frequencies of CYP2C19*2, CYP2C19*3 and CYP2C19*17 alleles and genotypes in Russian patients with peptic ulcer. Materials and Methods: The study involved 971 patients with peptic ulcer from the European part of Russia (Moscow), 428 male (44%) and 543 female (56%). The mean age was 44.6 ± 11.9 years (range 15–88 y). DNA isolated from blood samples was used for the analysis of CYP2C19 genetic polymorphisms (CYP2C19*2, *3, *17 alleles) by real-time polymerase chain reaction. Results: Regarding CYP2C19 genotype, 317 patients (32.65%) out of 971 were CYP2C19*1/*1 carriers classified as extensive metabolizers. Three hundred eighty-six (39.75%) with CYP2C19*1/*17 or CYP2C19*17/*17 genotype were ultrarapid metabolizers. Two hundred fifty-one people (25.85%) were intermediate metabolizers with CYP2C19*1/*2, CYP2C19*2/*17, CYP2C19*1/*3, CYP2C19*3/*17 genotypes. Seventeen patients (1.75%) with CYP2C19*2/*2, CYP2C19*3/*3, CYP2C19*2/*3 genotypes were poor metabolizers. The allele frequencies were the following: CYP2C19*2 – 0.140, CYP2C19*3 – 0.006, CYP2C19*17 – 0.274. Conclusion: There is a high frequency of CYP2C19 genotypes associated with modified response on proton pump inhibitors in Russian patients with peptic ulcer. Genotyping for CYP2C19 polymorphisms is suggested to be a useful tool for personalized dosing of proton pump inhibitors.

The frequency of CYP2C19 genetic polymorphisms in Russian patients with peptic ulcers treated with proton pump inhibitors.

IntroductionProton pump inhibitors, which are widely used as acid-inhibitory agents for the treatment of peptic ulcers, are mainly metabolized by 2C19 isoenzyme of cytochrome P450 (CYP2C19). CYP2C19 has genetic polymorphisms, associated with extensive, poor, intermediate or ultra-rapid metabolism of proton pump inhibitors. Genetic polymorphisms of CYP2C19 could be of clinical concern in the treatment of peptic ulcers with proton pump inhibitors.AimTo investigate the frequencies of CYP2C19*2, CYP2C19*3, and CYP2C19*17 alleles and genotypes in Russian patients with peptic ulcers.MethodsWe retrospectively reviewed the cases of 971 patients of Caucasian origin with Russian nationality from Moscow region with endoscopically and histologically proven ulcers, 428 males (44%) and 543 females (56%). The mean age was 44.6±11.9 years (range: 15–88 years). DNA was extracted from ethylenediaminetetraacetic acid whole blood samples (10 mL). The polymorphisms CYP2C19 681G.A (CYP2C19*2, rs4244285), CYP2C19 636 G.A (CYP2C19*3, rs4986893) and CYP2C19 -806 C.T (CYP2C19*17, rs12248560) were evaluated using real-time polymerase chain reaction.ResultsRegarding CYP2C19 genotype, 317 patients (32.65%) out of 971 were CYP2C19*1/*1 carriers classified as extensive metabolizers. Three hundred and eighty-six (39.75%) with CYP2C19*1/*17 or CYP2C19*17/*17 genotype were ultra-rapid metabolizers. Two hundred and fifty-one people (25.85%) were intermediate metabolizers with CYP2C19*1/*2, CYP2C19*2/*17, CYP2C19*1/*3, CYP2C19*3/*17 genotypes. Seventeen patients (1.75%) with CYP2C19*2/*2, CYP2C19*3/*3, CYP2C19*2/*3 genotypes were poor metabolizers. The allele frequencies were the following: CYP2C19*2 – 0.140, CYP2C19*3 – 0.006, CYP2C19*17 – 0.274.ConclusionThere is a high frequency of CYP2C19 genotypes associated with modified response to proton pump inhibitors in Russian patients with peptic ulcers. Genotyping for CYP2C19 polymorphisms is suggested to be a useful tool for personalized dosing of proton pump inhibitors.