Are the orally administered proton pump inhibitors equivalent? A comparison of lansoprazole, omeprazole, pantoprazole, and rabeprazole

Assessment of the efficacy of on-demand tegoprazan therapy in gastroesophageal reflux disease through a randomized controlled trial

In patients with gastroesophageal reflux disease (GERD) whose symptoms improve with acid-suppression therapy, on-demand treatment could constitute maintenance therapy. This study investigated the comparative efficacy and safety of on-demand tegoprazan and proton-pump inhibitor (PPI) therapy in GERD. From six university hospitals in the Daejeon-Chungcheong region, we enrolled patients with GERD who had experienced symptomatic improvement with acid-suppressive therapy and, using a randomization table, randomly allocated these participants to two groups: to receive either tegoprazan 50 mg + esomeprazole placebo or tegoprazan placebo + esomeprazole 20 mg, respectively. The primary endpoint of this study was the intergroup difference in patient satisfaction with on-demand therapy. Among the 69 participants who completed 8 weeks of on-demand therapy and rated patient satisfaction on a 5-point Likert scale, the tegoprazan and esomeprazole groups scored an average of 4.31 and 4.15 points, respectively, without any significant intergroup difference. In the tegoprazan group, 26.2% (182/694) of those with episodes experienced symptom improvement within 30 min, which is a significantly higher proportion compared to 16.1% (104/646) in the esomeprazole group. Compared to the esomeprazole group, the tegoprazan group had a significantly shorter time to symptom improvement overall and a significantly higher proportion of patients who improved within 30 min. No serious treatment-emergent adverse events were reported. Tegoprazan is effective as on-demand therapy for GERD and offers the expectation of faster symptom improvement than with PPIs. Clinical trial KCT0009296, registered at cris.nih.go.kr.

Time-Varying Use of Proton Pump Inhibitors and Cognitive Impairment and Dementia: A Real-World Analysis from Germany

BACKGROUND

Cumulative evidence of dementia risk in patients taking proton pump inhibitors (PPIs) is still inconclusive, probably due to a variety of study designs.

OBJECTIVE

This study aimed to compare how the association between dementia risk and use of PPIs differs by different outcome and exposure definitions.

METHODS

We conceptualized a target trial using claims data with 7,696,127 individuals aged 40 years or older without previous dementia or mild cognitive impairment (MCI) from the Association of Statutory Health Insurance Physicians in Bavaria. Dementia was defined as either including or excluding MCI to compare how the results alter by different outcome definitions. We used weighted Cox models to estimate the PPI initiation effect on dementia risk and weighted pooled logistic regression to assess the effect of time-varying use versus non-use during 9 years of study period, including 1 year of wash-out period (2009-2018). The median follow-up time of PPI initiators and non-initiators was 5.4 and 5.8 years, respectively. We also evaluated the association between each PPI agent (omeprazole, pantoprazole, lansoprazole, esomeprazole, and combined use) and dementia risk.

RESULTS

A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk. A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.A total of 105,220 (3.6%) PPI initiators and 74,697 (2.6%) non-initiators were diagnosed with dementia. Comparing PPI initiation with no initiation, the hazard ratio (HR) for dementia was 1.04 [95% confidence interval (CI) 1.03-1.05]. The HR for time-varying PPI use versus non-use was 1.85 (1.80-1.90). When MCI was included in the outcome, the number of outcomes increased to 121,922 in PPI initiators and 86,954 in non-initiators, but HRs remained similar, showing 1.04 (1.03-1.05) and 1.82 (1.77-1.86), respectively. Pantoprazole was the most frequently used PPI agent. Although the estimated HRs for the time-varying use effect of each PPI showed different ranges, all agents were associated with an increased dementia risk.

CONCLUSION

Our large study supports existing evidence that PPI use is related to an increased risk of dementia.

Who gets prescriptions for proton pump inhibitors and why? A drug-utilization study with claims data in Bavaria, Germany, 2010-2018

PURPOSE

The German annual drug prescription-report has indicated overuse of proton pump inhibitors (PPIs) for many years; however, little was known about the characteristics of people using PPIs. This study aimed to provide comprehensive utilization data and describe frequencies of potential on- and off-label PPI-indications in Bavaria, Germany.

METHODS

Claims data of statutorily insured people from 2010 to 2018 were used. Defined daily doses (DDDs) of PPIs by type of drug, prevalence of PPI-use and DDDs prescribed per 1000 insured people/day were analyzed. For 2018, proportions of users and DDDs per 1000 insured people were calculated by age and sex. To elucidate changes in prescribing practices due to a suspected drug-drug interaction, we examined co-prescribing of clopidogrel and PPIs between 2010 and 2018. For PPI new users, sums of DDDs and frequencies of potential indications were examined.

RESULTS

PPI prescribing increased linearly from 2010 to 2016 and gradually decreased from 2016 to 2018. In 2018, 14.7% of women and 12.2% of men received at least one prescription, and 64.8 DDDs (WHO-def.) per 1000 insured people/day were prescribed. Overall, omeprazole use decreased over the observation period and was steadily replaced by pantoprazole, especially when co-prescibed with clopidogrel. An on-label PPI-indication was not reported at first intake in 52.0% of new users.

CONCLUSIONS

The utilization of prescribed PPIs has decreased since 2016. However, a large proportion of new PPI-users had no documentation of a potential indication, and the sums of DDDs prescribed often seemed not to comply with guidelines.

Standard triple therapy in Helicobacter pylori eradication in Turkey: Systematic evaluation and meta-analysis of 10-year studies

BACKGROUND/AIMS

This study aims at evaluating the mean eradication rate by a systematic compilation of the studies which involved the standard triple therapy (STT) in first-line Helicobacter pylori (Hp) eradication in Turkey over a period of 10 years between 2004 and 2013 using the meta-analysis method.

MATERIALS AND METHODS

The systematic compilation and meta-analysis were carried out according to the PRISMA standards defined in the Cochrane handbook. The results of full-text studies published in national and international journals in English and Turkish languages on Turkish population in a period of 10 years, from 2004 to 2013, are included in this study. The studies include open-label trials, controlled trials, treatment arms, and case series that included a triple therapy regimen consisting of standard doses of a proton pump inhibitor (PPI; omeprazole 20 mg BID, lansoprazole 30 mg BID, pantoprazole 40 mg BID, esomeprazole 40 mg BID, or rabeprazole 20 mg BID) along with clarithromycin 500 mg BID and amoxicillin 1 g BID for 7-14 days. They were scanned electronically via the search engines Google Scholar, PubMed, and the Turkish Medicine Index using specific keywords. The related keywords used were Turkey, Helicobacter pylori, infection, standard triple treatment, first-line therapy, eradication, omeprazole, lansoprazole, pantoprazole, rabeprazole, esomeprazole, clarithromycin, and amoxicillin. Studies carried out with adults were included in the evaluation. The publication year of the studies and the included number of patients, their age, gender, treatment duration (7, 10, and 14 days), and PPIs used were evaluated by two separate gastroenterologists and biostatisticians. Studies that used at least one reliable method (histology, urea breath test (UBT), or Helicobacter pylori stool antigen (HpSA) test) four weeks after completing the treatment for the control of Hp eradication were included. Only naive patients were accepted, and patients who had previously received eradication treatment were excluded. The effectiveness of the Hp eradication was analyzed using an intention-to-treat (ITT) or per-protocol (PP) analysis.

RESULTS

The STT regime of 45 studies complying with the inclusion criteria was evaluated. A total of 3715 patients were included in the study. Of the 3010 patients whose gender information was available, 55% were women and 45% were men; the weighted age average given explicitly in the studies was 42.14±0.67. The treatment lasted for 14 days in 42 studies, for 7 days in six studies, and for 10 days in 1 study. The eradication rates evaluated according to the ITT and PP analyses were 60% (95% CI: 56%-63%) and 57% (95% CI: 51%-62%), respectively. The rates for 7 days of treatment were 57% (95% CI: 46%-68%) and 60% (95% CI: 51%-67%) and for 14 days of treatment were 60% (95% CI: 56%-63%) and 56% (95% CI: 50%-62%), respectively. The ITT eradication rate of the only 10-day study was 78% (95% CI: 66%-86%). In the meta-regression analysis, the treatment duration, PPI, age, and gender ratio (women/men) used for the ITT analysis had no effect. The gender ratio and age were not considered in this analysis because they were not clearly stated in studies using the PP analysis. The duration of treatment and the PPI used had no effect.

CONCLUSION

A systematic meta-analysis of studies conducted during the period 2004-2013 in Turkey revealed that the rate of first-line Hp eradication using STT was unacceptably low, and the duration of treatment and PPI used made no difference.

Ontology-based literature mining and class effect analysis of adverse drug reactions associated with neuropathy-inducing drugs

BACKGROUND

Adverse drug reactions (ADRs), also called as drug adverse events (AEs), are reported in the FDA drug labels; however, it is a big challenge to properly retrieve and analyze the ADRs and their potential relationships from textual data. Previously, we identified and ontologically modeled over 240 drugs that can induce peripheral neuropathy through mining public drug-related databases and drug labels. However, the ADR mechanisms of these drugs are still unclear. In this study, we aimed to develop an ontology-based literature mining system to identify ADRs from drug labels and to elucidate potential mechanisms of the neuropathy-inducing drugs (NIDs).

RESULTS

We developed and applied an ontology-based SciMiner literature mining strategy to mine ADRs from the drug labels provided in the Text Analysis Conference (TAC) 2017, which included drug labels for 53 neuropathy-inducing drugs (NIDs). We identified an average of 243 ADRs per NID and constructed an ADR-ADR network, which consists of 29 ADR nodes and 149 edges, including only those ADR-ADR pairs found in at least 50% of NIDs. Comparison to the ADR-ADR network of non-NIDs revealed that the ADRs such as pruritus, pyrexia, thrombocytopenia, nervousness, asthenia, acute lymphocytic leukaemia were highly enriched in the NID network. Our ChEBI-based ontology analysis identified three benzimidazole NIDs (i.e., lansoprazole, omeprazole, and pantoprazole), which were associated with 43 ADRs. Based on ontology-based drug class effect definition, the benzimidazole drug group has a drug class effect on all of these 43 ADRs. Many of these 43 ADRs also exist in the enriched NID ADR network. Our Ontology of Adverse Events (OAE) classification further found that these 43 benzimidazole-related ADRs were distributed in many systems, primarily in behavioral and neurological, digestive, skin, and immune systems.

CONCLUSIONS

Our study demonstrates that ontology-based literature mining and network analysis can efficiently identify and study specific group of drugs and their associated ADRs. Furthermore, our analysis of drug class effects identified 3 benzimidazole drugs sharing 43 ADRs, leading to new hypothesis generation and possible mechanism understanding of drug-induced peripheral neuropathy.

PREDICTING EFFICACY OF PROTON PUMP INHIBITORS IN REGULATING GASTRIC ACID SECRETION

Developing drugs to treat gastric acid related illnesses such as ulcers and acid reflux disease is the leading focus of pharmaceutical companies. In fact, expenditure for treating these disorders is highest among all illnesses in the US. Over the last few decades, a class of drugs known as a proton pump inhibitors (PPIs) appeared on the market and are highly effective at abating gastric illnesses by raising stomach pH (reducing gastric acid levels). While much is known about the action of PPIs , there are still open questions regarding their efficacy, dosing and long-term effects. Here we extend a previous gastric acid secretion model developed by our group to incorporate a pharmacodynamic/pharmacokinetic model to study proton pump inhibitor (PPI) action. Model-relevant parameters for specific drugs such as omeprazole (OPZ) , lansoprazole (LPZ) and pantoprazole (PPZ) were used from published data, and we conducted simulations to study various aspects of PPI treatment. Clinical data suggests that duration of acid suppression is dependent on proton pump turnover rates and this is supported by our model. We found the order of efficacy of the different PPIs to be OPZ>PPZ>LPZ for clinically recommended dose values, and OPZ>PPZ=LPZ for equal doses. Our results indicate that a breakfast dose for once-daily dosing regimens and a breakfast-lunch dose for twice-daily dosing regimens is recommended. Simulation of other gastric disorders using our model provides atypical applications for the study of drug treatment on homeostatic systems and identification of potential side-effects.

Eradication of Helicobacter pylori with triple therapy: an epidemiologic analysis of trends in Turkey over 10 years

BACKGROUND

There is increasing concern about the efficacy of current regimens for the eradication of Helicobacter pylori.

OBJECTIVES

This study examined rates of H. pylori eradication with a commonly used triple-therapy regimen consisting of a proton pump inhibitor (PPI), clarithromycin, and amoxicillin in trials performed in Turkey from 1996 to 2005. It also investigated the relationship between eradication rates and the duration of treatment (7, 10, or 14 days), choice of PPI, and indication for treatment (dyspepsia or peptic ulcer).

METHODS

This was a retrospective epidemiologic analysis. Articles concerning H. pylori eradication in Turkey that were published in peer-reviewed national and international journals were identified through searches of MEDLINE using the terms Helicobacter, eradication, and Turkey, and of the Turkish Medical Index using the terms Helicobacter and eradication. Abstracts from the Turkish Gastroenterology Congress from 1996 through 2005 were searched manually. Open-label trials, controlled trials, treatment arms, and case series that included a triple-therapy regimen consisting of standard doses of any PPI (omeprazole 20 mg BID, lansoprazole 30 mg BID, pantoprazole 40 mg BID, or esomeprazole 40 mg BID) with clarithromycin 500 mg BID and amoxicillin 1 g BID for 7 to 14 days were selected for analysis. Trials including patients who had undergone a previous attempt at eradication of H. pylori were excluded.

RESULTS

Of 138 trials or treatment arms identified, 94 met the criteria for inclusion (3637 subjects). The pooled eradication rate was 68.8% (95% CI, 67.3-70.3). A marked decrease in eradication was noted after 2000. Pooled eradication rates each year from 1996 through 2005 were 79.4%, 83.7%, 81.8%, 81.8%, 75.1%, 61.3%, 65.6%, 65.1%, 55.3%, and 61.1%, respectively. Eradication rates were not affected by the duration of treatment, choice of PPI, or indication for treatment.

CONCLUSIONS

Rates of H. pylori eradication with the triple-therapy regimen decreased in Turkey over the 10-year period studied. In an era of increasing clarithromycin use, the effectiveness of this regimen for H. pylori eradication appears to require reassessment.

An open-label study of rabeprazole in patients with Zollinger-Ellison syndrome or idiopathic gastric acid hypersecretion

BACKGROUND

Omeprazole and lansoprazole are both of proven efficacy in the treatment of Zollinger-Ellison syndrome and idiopathic gastric acid hypersecretion. Rabeprazole, which has a similar mechanism of action, has not previously been studied in these diseases.

AIM

To determine the dose of rabeprazole that decreased basal acid output to safe levels in patients with Zollinger-Ellison syndrome or idiopathic gastric acid hypersecretion.

METHODS

Patients with Zollinger-Ellison syndrome or idiopathic gastric acid hypersecretion were given rabeprazole 60 mg once daily for uncomplicated disease or 40 mg twice daily for complicated disease. Doses were titrated according to response and continued for 2 years. Efficacy was assessed primarily by measuring basal acid output.

RESULTS

All patients had basal acid output before the next dose controlled to <10 mmol/h either at the starting dose or after minor dose titration. Control of acid output was maintained for 2 years. Consistent with this, most patients reported few gastrointestinal symptoms. Gastric biopsy showed no enterochromaffin-like cell dysplasia or neoplasia.

CONCLUSIONS

Rabeprazole was an effective and well-tolerated treatment for Zollinger-Ellison syndrome or idiopathic gastric acid hypersecretion, which reliably reduced gastric acid output to safe levels. Although a dose of 60 mg once daily was appropriate for most patients in this study, doses may need adjustment according to individual response.

The power of pharmacological sciences: the example of proton pump inhibitors

Critics have questioned the foundational principles of pharmacological sciences and modern drug therapy; they also claim that drug therapy is often too expensive or of uncertain value. Contemporaneously, alternative medicine has bloomed. Yet the US government began to pay for drug therapy under Medicare in 2006, an explicit recognition of the value of modern drug therapy. To clarify this confusion, we review the philosophical and scientific foundations of pharmacology, drug discovery and development, the attendant strategies and successful results. We also review and answer the major attacks on the philosophical and scientific foundations of modern pharmacology and drug therapy. Finally, we define the characteristics of an ideal drug. As an example of the principles and strategies of modern pharmacological sciences and their successful application, we focus on the discovery and development of proton pump inhibitors (PPIs) of stomach acid production. This class of drugs approaches the ideal and exemplifies successful application of modern pharmacological principles to drug discovery and development. Moreover, the use of PPIs as a pharmacological tool allowed the resolution of important scientific questions, e.g., the role of stomach acid in peptic diseases of the stomach, duodenum and esophagus.

Possible Interethnic Differences in Omeprazole Pharmacokinetics

BACKGROUND AND OBJECTIVE

Considerable ethnic differences have been reported in the incidence of the poor metaboliser (PM) genotype of cytochrome P450 (CYP) 2C19. The frequency of this genotype was found to be much higher in Oriental persons (13-23%) than in American or European populations (3-5%). There are, however, no valid data published for Arabic subjects. The present study was conducted to evaluate pharmacokinetic parameters of omeprazole after a single dose in healthy Jordanian Arabic subjects and to compare the results with data published for other populations.

METHODS

Seventy-four healthy male Jordanian Arabic volunteers contributed to the study, which was performed at Al Essra Hospital in Amman, Jordan. After an overnight fast, omeprazole was administered as a single Losec 20mg capsule. A total of 20 blood samples were collected over a 10-hour period after administration. Omeprazole pharmacokinetic parameters were determined from the plasma concentration-time profiles using the WinNonlin software. Kolmogorov-Smirnov's test and probit plots of omeprazole area under the plasma concentration-time curve (AUC) data were used to analyse the frequency distribution of phenotypic data.

RESULTS

The mean pharmacokinetic parameters and their corresponding coefficient of variation (CV%) for peak plasma concentration (Cmax), AUC from time zero to infinity (AUCinfinity), time to reach Cmax (tmax), apparent oral clearance (CL/F) and elimination half-life (t(1/2)) were 314.96 ng/mL (56%), 923.2 ng . h/mL (108.6%), 2.1h (44%), 0.66 L/h/kg (92%) and 1.5 h (56.6%), respectively. Interindividual differences in the current study were high for all pharmacokinetic parameters, yet comparable to CVs reported in nonphenotyped subjects identified within other ethnic groups (40.3-159% for AUC and 39-48.2% for Cmax). The frequency distribution of all parameters, particularly the AUC, was shown to be trimodal. This has proposed the presence of three distinct phenotypes, designated as extensive metabolisers (EMs), slow-extensive metabolisers (SEMs), and PMs, with corresponding frequency of 36.5%, 39.2% and 24.3%, respectively. After stratification, the relative mean AUCs of omeprazole in EMs, SEMs and PMs were 1 : 2.7 : 9.3 (all p < 0.001). Accordingly, the CL/F of omeprazole showed a ratio of 9.8 : 3.6 : 1 for three phenotype groups, respectively. For other pharmacokinetic parameters including Cmax, t1/2, AUC normalised for bodyweight (AUCN), Cmax/dose and AUC/dose, there were also significant differences between the three groups.

CONCLUSIONS

The current pharmacokinetic study revealed that the majority of the Jordanian Arabics seemed to be more properly classified within the EM phenotype. More specifically, the observed metabolic rates of heterozygous and homozygous Jordanian Arabic EMs were more comparable to those of Caucasian EMs than Oriental EMs. Consequently, higher dosage requirements can be expected among most of the Jordanian Arabics. Yet, the incidence of PMs is significant and they seemed to exhibit a similar pharmacokinetic pattern to Chinese PMs in terms of long-term exposure (clearance and AUC) as well as short-term exposure (Cmax) parameters, after adjustment for dose and bodyweight. Therefore, further clinical application of CYP2C19 polymorphism is anticipated in Jordanian Arabic mixed population, particularly if long-term use of omeprazole is intended.

Treatment of Zollinger-Ellison Syndrome

In this article, we have reviewed the main therapeutic measures for the treatment of Zollinger-Ellison syndrome (ZES). Review of the literature was based on computer searches (Pub-Med, Index Medicus) and personal experiences. We have evaluated all the measures now available for treating patients with sporadic gastrinomas or gastrinomas associated with Multiple Endocrine Neoplasia Type 1, (MEN 1) including medical therapy such as antisecretory drugs and somatostatin analogs (SST), chemotherapy and chemoembolization, and surgical procedures. In ZES patients, the best therapeutic procedure is surgery which, if radical, can be curative. Medical treatment can be the best palliative therapy and should be used, when possible, in association with surgery, in a multimodal therapeutic approach.

Potent Gastric Acid Inhibition in Helicobacter pylori Eradication

At present, antisecretory drugs--foremost among them the proton pump inhibitors (PPIs)--represent a keystone in Helicobacter pylori eradication therapy. The present article shall first compare the role of PPIs as compared with histamine H2 receptor antagonists, both of them in the role of antibiotic-associated antisecretory therapy, and shall then address the contribution of each of the various PPIs that have been developed until the present time to the H. pylori eradication therapies. In summary, it may be concluded that PPIs are more effective overall than H2 receptor antagonists when the two groups of antisecretory drugs are given at the usual standard doses together with antibiotics with the intention of eradicating H. pylori infection. However, all PPIs (omeprazole, lansoprazole, pantoprazole, rabeprazole, and esomeprazole) are equivalent when given together with two antibiotics to cure the infection.

Review article: the pharmacodynamics and pharmacokinetics of proton pump inhibitors--overview and clinical implications

During the past two decades, enormous changes occurred in the management of gastric acid-related diseases. First, the histamine2-receptor antagonists were introduced, offering patients the first single-agent therapy that effectively reduced gastric acid secretion. Proton pump inhibitors became widely available in the early 1990s, and they generally appeared to be superior to the histamine2-receptor antagonists in acid-suppressing activity, symptom control and healing. Most physicians now use proton pump inhibitors as first-line treatment for many patients with acid-peptic disorders, including erosive gastro-oesophageal reflux disease (GERD), nonerosive reflux disease (NERD) and duodenal and gastric ulcers. Although proton pump inhibitors are often thought to be interchangeable, some differences have emerged in their pharmacological properties, which may be reflected in some aspects of clinical efficacy. Such differences include potency, speed of onset and duration of pH 'holding times'. Helicobacter pylori has now been recognized as an important factor in the pathogenesis of acid-peptic disorders. It is clear that H. pylori eradication can dramatically reduce the chronicity of gastric and duodenal ulcers, and accepted therapeutic regimens for H. pylori eradication now include proton pump inhibitors and two or more antibiotics. Although all accepted proton pump inhibitor-based 'triple therapies' are roughly equivalent in efficacy, there is now a shortened regimen available that will potentially enhance compliance and decrease cost. This review examines the relative advantages of proton pump inhibitors vs. histamine2-receptor antagonists in the context of acid suppression and in various gastric acid-related diseases. A brief overview presents the pharmacodynamics and pharmacokinetics of the proton pump inhibitors with particular attention paid to rabeprazole, one of the newer drugs in its class.

Pantoprazole based therapies in Helicobacter pylori eradication: a systematic review and meta-analysis

AIM

To perform a systematic review on the efficacy of pantoprazole based therapies in Helicobacter pylori eradication, and to conduct a meta-analysis comparing the efficacy of pantoprazole and other proton pump inhibitors (PPIs) when co-prescribed with antibiotics.

METHODS

Studies evaluating pantoprazole combined with antibiotics were considered. Only randomized clinical trials comparing pantoprazole and other PPIs when co-prescribed with antibiotics, and differing only in the PPI (pantoprazole vs other), were eligible for inclusion in the meta-analysis. Bibliographical searches in several electronic databases, and manual search of abstracts from congresses, were conducted. The percentage (weighted mean) of patients with eradication success was calculated. Meta-analysis was performed combining the odds ratios (ORs) of the individual studies in a global OR.

RESULTS

The mean eradication rate with pantoprazole plus clarithromycin for 14 days was 60%. Cure rates with 7 day pantoprazole based triple regimens were higher: pantoprazole, amoxicillin and clarithromycin (78%); pantoprazole, clarithromycin and nitroimidazole (84%); and pantoprazole, amoxicillin and nitroimidazole (74%). Twelve studies comparing pantoprazole and other PPIs were selected for the meta-analysis, including 534 and 603 patients, respectively. The mean eradication rate for H. pylori using pantoprazole plus antibiotics was 83%, and 81% when other PPIs were used (OR = 1; 95% confidence interval (CI) from 0.61 to 1.64). When sub-analysis was performed, including only studies comparing pantoprazole with omeprazole, or pantoprazole with lansoprazole, differences were also statistically non-significant. The meta-analysis of the six studies prescribing equivalent doses of all PPIs demonstrated similar results with pantoprazole and with other PPIs (OR = 1.07; 95% CI from 0.71 to 1.62), the results being statistically homogeneous.

CONCLUSIONS

Pantoprazole achieves similar cure rates to those of omeprazole and lansoprazole when co-prescribed with antibiotics for the eradication of H. pylori infection.

Meta-analysis: comparative efficacy of different proton-pump inhibitors in triple therapy for Helicobacter pylori eradication

BACKGROUND

It is not known whether certain proton-pump inhibitors are more efficacious than others when used in triple therapy for Helicobacter pylori eradication.

AIM

To compare the efficacy of different proton-pump inhibitors in triple therapy by performing a meta-analysis.

METHODS

A MEDLINE search was performed. Abstracts of the European Helicobacter pylori Study Group and the American Gastroenterological Association congresses from 1996 to 2002 were also examined. Randomized studies with at least two branches of triple therapy that differed only in terms of type of proton-pump inhibitor were included in a meta-analysis using Review Manager 4.1.

RESULTS

Fourteen studies were included. Intention-to-treat cure rates were similar for omeprazole and lansoprazole: 74.7% vs. 76%, odds ratio (OR) 0.91 [95% confidence interval (CI) 0.69-1.21] in a total of 1085 patients; for omeprazole and rabeprazole: 77.9% vs. 81.2%, OR 0.81 (95% CI 0.58-1.15) in a total of 825 patients; for omeprazole and esomeprazole: 87.7% vs. 89%, OR 0.89 (95% CI 0.58-1.35) in 833 patients; and for lansoprazole and rabeprazole: 81% vs. 85.7%, OR 0.77 (95% CI 0.48-1.22) in 550 patients.

CONCLUSION

The efficacy of various proton-pump inhibitors seems to be similar when used for H. pylori eradication in standard triple therapy.

Improvement of gastroesophageal reflux symptoms after radiofrequency energy: a randomized, sham-controlled trial

BACKGROUND & AIMS

Gastroesophageal reflux disease is a prevalent disorder that often requires long-term medical therapy or surgery. The United States Food and Drug Administration recently cleared new endoluminal gastroesophageal reflux disease treatments; however, no controlled trials exist.

METHODS

We randomly assigned 64 gastroesophageal reflux disease patients to radiofrequency energy delivery to the gastroesophageal junction (35 patients) or to a sham procedure (29 patients). Principal outcomes were reflux symptoms and quality of life. Secondary outcomes were medication use and esophageal acid exposure. After 6 months, interested sham patients crossed over to active treatment.

RESULTS

At 6 months, active treatment significantly and substantially improved patients' heartburn symptoms and quality of life. More active vs. sham patients were without daily heartburn symptoms (n = 19 [61%] vs. n = 7 [33%]; P = 0.05), and more had a >50% improvement in their gastroesophageal reflux disease quality of life score (n = 19 [61%] vs. n = 6 [30%]; P = 0.03). Symptom improvements persisted at 12 months after treatment. At 6 months, there were no differences in daily medication use after a medication withdrawal protocol (n = 17 [55%] vs. n = 14 [61%]; P = 0.67) or in esophageal acid exposure times. There were no perforations or deaths.

CONCLUSIONS

Radiofrequency energy delivery significantly improved gastroesophageal reflux disease symptoms and quality of life compared with a sham procedure, but it did not decrease esophageal acid exposure or medication use at 6 months. This procedure represents a new option for selected symptomatic gastroesophageal reflux disease patients who are intolerant of, or desire an alternative to, traditional medical therapies.

Optimal Treatment of Zollinger-Ellison Syndrome and Related Conditions in Elderly Patients

Zollinger-Ellison syndrome is characterised by refractory peptic ulcer disease, severe diarrhoea and gastric acid hypersecretion associated with an islet-cell tumour of the pancreas (gastrinoma). The true incidence and prevalence of this rare disease is unknown; in the US, the frequency is one per one million people and the age at presentation varies from 7 to 90 years. Zollinger-Ellison syndrome is sporadic in 62-80% of cases and in 20-38% of cases is associated with multiple endocrine neoplasia type 1 (MEN 1). The diagnosis of Zollinger-Ellison syndrome is certain when the plasma gastrin is >1000 pg/mL and the basal acid output is >15 mEq/h in patients with an intact stomach, >5 mEq/h in gastrectomised patients, or when this hypergastrinemia is associated with a pH <2. The treatment is based on control of gastric acid hypersecretion and of the malignant tumour and its possible metastases. Proton pump inhibitors are the most effective antisecretory drugs and can be administered in the elderly at high dosages without drug-related adverse effects. As an initial therapy, daily dosages of omeprazole 80-100 mg or pantoprazole 40-160 mg are employed. In long-term treatment the doses can be greatly reduced once effective control of the gastric output has been established. Intravenous proton pump inhibitors may be administered when patients cannot take oral therapy, particularly in acute conditions. All sporadic localised gastrinomas should be excised if possible. When liver metastases are also present, their debulking may improve symptoms and survival, and facilitate medical treatment. There is some controversy as to the surgical approach for gastrinomas associated with MEN 1. Somatostatin analogues can be useful in reducing gastric acid hypersecretion, serum gastrin and gastric enterochromaffin-like (ECL) cells and can thus contribute to treating the disease more effectively. Their antiproliferative effect can be used in treating liver metastases. Chemotherapy is not the therapy of choice in patients with gastrinomas and is indicated only in those with malignant progressive disease; interferon alpha, embolisation and chemoembolisation are not advisable for the elderly. The treatment of elderly Zollinger-Ellison syndrome patients, similarly to all elderly oncological patients, should be based on the use of comprehensive geriatric assessment. This will enable the clinician to define the functional status of the elderly person, to decide whether the patient can tolerate surgery and/or the stress of antineoplastic therapy, and finally, to determine whether this patient can tolerate an aggressive treatment for Zollinger-Ellison syndrome or whether the only possible choice is palliative relief of symptoms.

Clinical significance of the cytochrome P450 2C19 genetic polymorphism

Cytochrome P450 2C19 (CYP2C19) is the main (or partial) cause for large differences in the pharmacokinetics of a number of clinically important drugs. On the basis of their ability to metabolise (S)-mephenytoin or other CYP2C19 substrates, individuals can be classified as extensive metabolisers (EMs) or poor metabolisers (PMs). Eight variant alleles (CYP2C19*2 to CYP2C19*8) that predict PMs have been identified. The distribution of EM and PM genotypes and phenotypes shows wide interethnic differences. Nongenetic factors such as enzyme inhibition and induction, old age and liver cirrhosis can also modulate CYP2C19 activity. In EMs, approximately 80% of doses of the proton pump inhibitors (PPIs) omeprazole, lansoprazole and pantoprazole seem to be cleared by CYP2C19, whereas CYP3A is more important in PMs. Five-fold higher exposure to these drugs is observed in PMs than in EMs of CYP2C19, and further increases occur during inhibition of CYP3A-catalysed alternative metabolic pathways in PMs. As a result, PMs of CYP2C19 experience more effective acid suppression and better healing of duodenal and gastric ulcers during treatment with omeprazole and lansoprazole compared with EMs. The pharmacoeconomic value of CYP2C19 genotyping remains unclear. Our calculations suggest that genotyping for CYP2C19 could save approximately 5000 US dollars for every 100 Asians tested, but none for Caucasian patients. Nevertheless, genotyping for the common alleles of CYP2C19 before initiating PPIs for the treatment of reflux disease and H. pylori infection is a cost effective tool to determine appropriate duration of treatment and dosage regimens. Altered CYP2C19 activity does not seem to increase the risk for adverse drug reactions/interactions of PPIs. Phenytoin plasma concentrations and toxicity have been shown to increase in patients taking inhibitors of CYP2C19 or who have variant alleles and, because of its narrow therapeutic range, genotyping of CYP2C19 in addition to CYP2C9 may be needed to optimise the dosage of phenytoin. Increased risk of toxicity of tricyclic antidepressants is likely in patients whose CYP2C19 and/or CYP2D6 activities are diminished. CYP2C19 is a major enzyme in proguanil activation to cycloguanil, but there are no clinical data that suggest that PMs of CYP2C19 are at a greater risk for failure of malaria prophylaxis or treatment. Diazepam clearance is clearly diminished in PMs or when inhibitors of CYP2C19 are coprescribed, but the clinical consequences are generally minimal. Finally, many studies have attempted to identify relationships between CYP2C19 genotype and phenotype and susceptibility to xenobiotic-induced disease, but none of these are compelling.

Helicobacter pylori infection: treatment

Current standard treatment regimens for Helicobacter pylori infection provide eradication rates 80 to 90%. These rates have been achieved with a variety of 1-week triple therapies using two antibiotics and an acid suppressant. Antibiotic resistance, which may develop during failed treatment, is becoming increasingly common and has led to studies of new regimens for primary therapy, and new strategies for salvage of failed therapy. Other regimens have been designed and tested with the aim of decreasing the cost of initial therapy or to improve compliance, but abbreviated regimens have high incidence of failure and may add to the problem of resistance. Increasing attention has been paid to the need for, and timing of, the determination of antibiotic resistance of H. pylori isolates either at the time of initial diagnosis or after treatment failure. New, simpler, and noninvasive methods are offered for follow-up to determine if eradication has been successful. Treatment regimens should be chosen based on local drug susceptibility patterns and the availability of approved therapeutic agents in each country. Established indications for testing for H. pylori and administering therapy include active or inactive peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, as well as hyperplastic polyps, hyperplastic gastropathy, postendoscopic resection for gastric malignancy, and acute H. pylori gastritis. It is now largely accepted that noninvestigated dyspepsia is an indication for testing for and treating H. pylori, but that dyspeptic symptoms shown not to be associated with ulcer (nonulcer dyspepsia) do not now provide an indication for testing. Controversial or unresolved indications for testing and treating include planned use of chronic antisecretory therapy, planned use of nonsteroidal anti-inflammatory drugs, and use as a general approach to the prevention of gastric cancer.

Helicobacter pylori: strategies for treatment

Helicobacter pylori (Hp) is a Gram-negative bacteria able to live in the human stomach, a very surprising fact considering the acid environment of gastric mucosa. Identified by Marshall and Warren in 1982 [1,2], this bacterium seems aetiologically related to many gastric diseases, previously known as 'acid related diseases'. Compelling evidence demonstrates that Hp is the most important aetiological agent of gastritis [3], the principal causal factor in peptic ulcer [4], contributes to the genesis of gastric cancer [5] and has a critical role in the development of many mucosa-associated lymphoid tissue (MALT) lymphomas [6]. Although experimental data have recently provided hard evidence to support the role of Hp in the genesis of gastritis, ulcer and carcinoma [7], a critical argument for Hp generating peptic ulcer disease has been, in fact, the change in the natural history of peptic ulcer that follows the cure of the infection.