Proton pump inhibitors: do differences in pharmacokinetics translate into differences in clinical outcomes?

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.

Potassium-competitive acid blockers and proton-pump inhibitors for healing of erosive esophagitis: a systematic review and network meta-analysis

Background

Proton-pump inhibitors (PPIs) and potassium-competitive acid blockers (P-CABs) are recommended for erosive esophagitis (EE), with good safety and tolerance. However, it is unclear which is the best treatment option for EE.

Objectives

This study aimed to evaluate the comparative efficacy of P-CABs and PPIs for healing EE patients, seeking an appropriate treatment choice in the 4- or 8-week treatment and standard or double dose.

Design

A systematic review and network meta-analysis.

Data sources and methods

Relevant databases were searched to collect randomized controlled trials of PPIs and P-CABs in the treatment of EE up to 31 May 2023. Studies on standard or double-dose PPIs or P-CABs which were published in English and assessed 4- or 8-week healing effects in EE were included. A network meta-analysis was performed to evaluate the efficacy of the treatments under the frequentist framework. Sensitivity and subgroup analyses of patients with different baseline EE were also conducted.

Results

In all, 34 studies involving 25,054 patients and 9 PPIs, 6 P-CABs, or placebo treatment interventions were included. The pooled 4-week healing rate was significantly statistically lower than the pooled 8-week healing rate for most treatments. Besides, the higher healing rate of double-dose treatment than standard-dose treatment was not observed in the initial treatment of most drugs. The main analysis only included studies conducted for both patients with and without severe EE at baseline, and the proportion of severe EE included in the study was >10%, Keverprazan 20 mg qd ranked best with a surface under the cumulative ranking curve (SUCRA) value of 84.7, followed by Ilaprazole 10 mg qd with a SUCRA value of 82.0, for the healing rate at 8 weeks. Sensitivity analysis showed that the results were robust. Subgroup analysis showed that most P-CABs had higher healing rates than PPIs, particularly for patients with severe EE. And the healing rate of Keverprazan 20 mg qd at 8 weeks ranked best in the subgroup without or with severe EE at baseline.

Conclusion

This study showed that an 8-week treatment seemed more effective than the 4-week treatment for healing EE patients. The healing effect of Keverprazan (20 mg qd) ranked best in 8-week treatment, for both severe and non-severe EE patients.

Trial registration

The study protocol was registered with INPLASY (registration number INPLASY2023120053).

P-CAB versus PPI in the eradication of Helicobacter pylori: a systematic review and network meta-analysis

Background

The efficacy and safety of potassium-competitive acid blockers (P-CABs) in the eradication of Helicobacter pylori (Hp) remains controversial when compared with proton pump inhibitors (PPIs).

Objectives

The current study set out to compare the differences in the eradication rate and adverse reactions between eradication regimens based on P-CAB or PPI drugs and the differences between the vonoprazan-based and the tegoprazan-based regimens to explore the efficacy and safety of different Hp eradication regimens.

Data sources and methods

Databases including PubMed, EMBASE, Cochrane Library, and WOS were searched from the inception of these databases up to July 2023, and eligible randomized controlled trials (RCTs) were included. The outcome measures were the eradication rate and the incidence of adverse reactions of different regimens in treating Hp. The results were estimated as relative risk (RR) and its 95% confidence interval (CI), and R 4.2.1 software was used to perform the network meta-analysis (NMA).

Results

A total of 20 studies were included in the analysis, involving 5815 patients with Hp. In terms of eradication rate, the 2-week vonoprazan-based triple regimen (V-Tri-2w) was the best, which was superior to the 2-week PPI-based quadruple regimen [P-Qua-2w, RR = 0.9, 95% CI: (0.85-0.95)] and the 1-week tegoprazan-based triple regimen [T-Tri-1w, RR = 0.79, 95% CI: (0.64-0.97)]; the 2-week tegoprazan-based quadruple regimen (T-Qua-2w) was superior to the 1-week PPI-based triple regimen [P-Tri-1w, RR = 0.82, 95% CI: (0.67-0.99)], and there was no difference between the remaining tegoprazan-based regimens and the PPI-based or vonoprazan-based regimens. In terms of the incidence of adverse reactions, the 2-week vonoprazan-based binary regimen (V-Bi-2w) was lower than that of the 2-week PPI-based quadruple regimen [P-Qua-2w, RR = 1.98, 95% CI: (1.57-2.52)]; there was no significant difference between 1 and 2 weeks for each regimen, such as the vonoprazan-based triple regimen [RR = 1.11, 95% CI: (0.82-1.52)].

Conclusion

In the eradication treatment of Hp, the efficacy and safety of vonoprazan-based regimens are generally better than those of PPI-based regimens. Among them, the V-Tri-2w regimen has the highest eradication rate and may be the preferred choice for Hp eradication.

Combined contributions of cytochrome P450s (CYPs) and non-enzymatic metabolism in the in vitro biotransformation of anaprazole, a novel proton pump inhibitor

Anaprazole, a new proton pump inhibitor (PPI), is designed for the treatment of acid-related diseases, such as gastric ulcers and gastroesophageal reflux. This study explored the in vitro metabolic transformation of anaprazole. The metabolic stabilities of anaprazole in human plasma and human liver microsomes (HLM) were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Then, the contribution (%) of non-enzymatic and cytochrome P450s (CYPs) enzyme-mediated anaprazole metabolism was assessed. To obtain the metabolic pathways of anaprazole, the metabolites generated in HLM, thermal deactivated HLM, and cDNA-expressed recombinant CYPs incubation systems were identified by ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS). Results showed that anaprazole was very stable in human plasma and unstable in HLM. The contribution (%) of non-enzymatic vs. CYPs enzyme-mediated metabolism was 49% vs. 51%. CYP3A4 was the major enzyme (48.3%), followed by CYP2C9 (17.7%) and CYP2C8 (12.3%), in responsible for the metabolism of anaprazole. Specific chemical inhibitors targeting CYP enzymes notably blocked the metabolic transformation of anaprazole. Six metabolites of anaprazole were identified in the non-enzymatic system, whereas 17 metabolites were generated in HLM. The biotransformation reactions mainly included sulfoxide reduction to thioether, sulfoxide oxidation to sulfone, deoxidation, dehydrogenation, O-dealkylation or O-demethylation of thioether, O-demethylation and dehydrogenation of thioether, O-dealkylation and dehydrogenation of thioether, thioether O-dealkylation and dehydrogenation of thioether, and O-dealkylation of sulfone. Both enzymatic and non-enzymatic metabolisms contribute to the clearance of anaprazole in human. Anaprazole is less likely to develop drug-drug interactions in clinical use compared to other PPIs.

Design and statistics of pharmacokinetic drug-drug, herb-drug, and food-drug interaction studies in oncology patients

Polypharmacy is becoming increasingly prevalent in society. Patients with polypharmacy are at greater risk for drug-drug interactions, which can influence the efficacy of treatment. Especially, in oncology this is a concern since neoplasms are increasing prevalent with age, as well as polypharmacy is. Besides drug-drug interactions, also herb-drug and food-drug interactions could be present. Knowledge of these interactions is of great importance for safe and effective anti-cancer treatment, because the therapeutic window of most of these oncologic drugs are small. To study pharmacokinetic interaction effects, a cross-over pharmacokinetic study is a widely used, efficient and scientifically robust design. Yet, several aspects need to be considered when carrying out an interaction study. This includes the knowledge of the advantages and disadvantages of a cross-over design. Furthermore, determination of the end point and research question of interest, calculation of the required sample size, analysis of the generated data with a robust statistical plan and consideration of the logtransformation for some pharmacokinetic parameters are important aspects to consider. Even though some guidelines exist regarding these key issues, no clear overview exists. In this article an overview of these aspects is provided and their effect is discussed.

Proton pump inhibitor-induced gut dysbiosis and immunomodulation: current knowledge and potential restoration by probiotics

Proton pump inhibitors (PPIs) are the most commonly prescribed drugs for the treatment of non-erosive reflux disease (NERD), ulcers associated with non-steroidal anti-inflammatory drugs (NSAIDs), esophagitis, peptic ulcer disease (PUD), Zollinger-Ellison syndrome (ZES), gastroesophageal reflux disease (GERD), non-ulcer dyspepsia, and Helicobacter pylori eradication therapy. The drugs have the effect of inhibiting acid production in the stomach. According to research, PPIs can affect the composition of gut microbiota and modulate the immune response. Recently, there has been a problem with the over-prescription of such drugs. Although PPIs do not have many side effects, their long-term use can contribute to small intestinal bacterial overgrowth (SIBO) or C. difficile and other intestinal infections. Probiotic supplementation during PPIs therapy may provide some hope in the reduction of emerging therapy side effects. This review aims to present the most important effects of long-term PPI use and provides critical insights into the role of probiotic intervention in PPI therapy.

Aspirin vs Clopidogrel: Antiplatelet Agent of Choice for Those With Recent Bleeding or at Risk for Gastrointestinal Bleed

Antiplatelet agents are used worldwide mainly for primary and secondary prevention of cardiovascular events on a long-term basis for mortality benefit. Gastrointestinal bleeding is a well-known adverse effect. Various factors are to be considered while choosing antiplatelet agents to prevent the risk of bleed and rebleed incidents. These range from deciding on the agent, timing of therapy, underlying indications, coadministration of proton pump inhibitor, etc. At the same time, one must weigh the risks of cardiovascular events secondary to the stoppage of antiplatelet therapy. With this review, we have tried to guide the clinician on decision-making regarding the care of patients on management of acute upper and lower gastrointestinal bleeding, stoppage, restarting of agents, and measures to prevent a recurrence. We have focused on aspirin and clopidogrel as they are among the most widely used antiplatelet agents.

Pharmacokinetic and pharmacodynamic properties of pantoprazole in calves

Introduction

Development of abomasal ulceration is a large concern, especially within calves; however, there is a paucity of research into the use of gastro protectants in ruminant species. Proton pump inhibitors, such as pantoprazole, are widely used in humans and companion animals. Their efficacy in ruminant species is undetermined. The objectives of this study were to 1) estimate the plasma pharmacokinetic parameters for pantoprazole in neonatal calves after three days of intravenous (IV) or subcutaneous (SC) administration, and 2) measure the effect pantoprazole had on abomasal pH over the treatment period.

Methods

Pantoprazole was administered to 6 Holstein-Angus cross bull calves at a dose of 1 mg/kg (IV) or 2 mg/kg (SC), once a day (every 24 h) for three days. Plasma samples were collected over a 72 h period and analyzed via HPLC-UV for determining pantoprazole concentrations. Pharmacokinetic parameters were derived via non-compartmental analysis. Abomasal (n= 8) samples were collected via abomasal cannulas over a 12 h period, per calf per day. Abomasal pH was determined via a bench top pH analyzer.

Results

Following Day 1 of IV administration, plasma clearance, elimination half-life, and volume of distribution of pantoprazole were estimated at 199.9 mL/kg/h, 1.44 h, and 0.51 L/kg, respectively. On Day 3 of IV administration, the reported values were 192.9 mL/kg/h, 2.52 h, and 1.80 L/kg mL, respectively. Elimination half-life and volume of distribution (V/F) of pantoprazole following SC administration were estimated at 1.81 h and 0.55 L/kg, respectively, on Day 1; and 2.99 h and 2.82 L/kg, respectively, on Day 3.

Discussion

The reported values for IV administration were similar to those previously reported in calves. SC administration appears to be well absorbed and tolerated. The sulfone metabolite was detectable for 36 h after the last administration for both routes. Abomasal pH was significantly higher than the pre-pantoprazole pH 4, 6, and 8 h after administration in both the IV and SC groups. Further studies of pantoprazole as a treatment/preventative for abomasal ulcers are warranted.

Size-reduced fexuprazan 20 mg demonstrated the optimal bioavailability and bioequivalence with the reference formulation

Fexuprazan (DWP14012), a potassium-competitive acid blocker, is a medical formulation prescribed to inhibit the secretion of gastric acid. The present study encompasses a comparative evaluation of pharmacokinetic (PK) analysis between the previous (reference) and size-reduced (test) formulation of fexuprazan 20 mg in healthy subjects. The study employed a randomized, open-label, single-dose, 2-sequence, 2-period, crossover design with a 7-day wash-out between periods. A total of 24 subjects were enrolled in this randomized study. During each period, the 21 subjects received either the test or reference formulation. Blood samples were collected at multiple time point ranging from 0 (pre-dose) to 48 hours post-dosing for PK analysis. The calculated PK parameters were considered bioequivalent when the 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) were within the bioequivalence limit of 0.8-1.25. Safety and tolerability were included in the evaluation. A total of 20 subjects completed the study. Point estimates (90% CIs) of the GMRs were 1.1014 (0.9892-1.2265) for the maximum plasma concentration and 1.0530 (0.9611-1.1536) for the area under the plasma concentration-time curve from zero to the time of the last quantifiable concentration, between the test and reference formulations. The reference and size-reduced test formulations of fexuprazan were well tolerated with no reports of serious adverse events. In conclusion, size-reduced and previous formulations of fexuprazan 20 mg were bioequivalent with regard to PKs, safety and tolerability.

Helicobacter Pylori: A Review of Current Treatment Options in Clinical Practice

BACKGROUND

When prescribing antibiotics, infection eradication rates, local resistance rates, and cost should be among the most essential considerations. Helicobacter pylori is among the most common infections worldwide, and it can lead to burdensome sequela for the patient and the healthcare system, without appropriate treatment. Due to constantly fluctuating resistance rates, regimens must be constantly assessed to ensure effectiveness.

METHODS

This was a narrative review. The sources for this review are as follows: searching on PubMed, Google Scholar, Medline, and ScienceDirect; using keywords: Helicobacter pylori, Treatment Options, Clinical Practice.

RESULTS

Multiple antibiotics are prescribed as part of the regimen to thwart high resistance rates. This can lead to unwanted adverse reactions and adherence issues, due to the amount and timing of medication administration, which also may contribute to resistance. Single-capsule combination capsules have reached the market to ease this concern, but brand-only may be problematic for patient affordability. Due to the previously mentioned factors, effectiveness and affordability must be equally considered.

CONCLUSIONS

This review will utilize guidelines to discuss current treatment options and give cost considerations to elicit the most effective regimen for the patient.

Efficacy of keverprazan for duodenal ulcer: A phase II randomized, double-blind, parallel-controlled trial

BACKGROUND AND AIM

Considering the limitation of varying acid suppression of proton pump inhibitors, this study was aimed to assess the efficacy, safety, and dose-effect relationship of keverprazan, a novel potassium-competitive acid blocker, in the treatment of duodenal ulcer (DU) compared with lansoprazole.

METHODS

A randomized, double-blind, double-dummy, multicenter, low-dose, high-dose, and positive-drug parallel-controlled study was conducted to verify the non-inferiority of keverprazan (20 or 30 mg) to lansoprazole of 30 mg once daily for 4 to 6 weeks and dose-effect relationship of keverprazan in the treatment of patients with active DU confirmed by endoscopy.

RESULTS

Of the 180 subjects randomized, including 55 cases in the keverprazan_20 mg group, 61 cases in the keverprazan_30 mg group, and 64 cases in the lansoprazole_30 mg group, 168 subjects (93.33%) completed the study. The proportions of healed DU subjects in the keverprazan_20 mg, keverprazan_30 mg, and lansoprazole_30 mg groups were respectively 87.27%, 90.16%, and 79.69% at week 4 (P = 0.4595) and were respectively 96.36%, 98.36%, and 92.19% at week 6 (P = 0.2577). The incidence of adverse events in the keverprazan_20 mg group was lower than that in the lansoprazole_30 mg (P = 0.0285) and keverprazan_30 mg groups (P = 0.0398).

CONCLUSIONS

Keverprazan was effective and non-inferior to lansoprazole in healing DU. Based on the comparable efficacy and safety data, keverprazan of 20 mg once daily is recommended for the follow-up study of acid-related disorders. (Trial registration number: ChiCTR2100043455.).

The efficacy and safety of keverprazan, a novel potassium-competitive acid blocker, in treating erosive oesophagitis: a phase III, randomised, double-blind multicentre study

BACKGROUND

Keverprazan is a novel potassium-competitive acid blocker (P-CAB) with a strong acid-suppressive capacity that may provide clinical benefit in acid-related diseases.

AIMS

This study aimed to explore the non-inferior efficacy and safety of keverprazan to lansoprazole in treating erosive oesophagitis (EO).

METHODS

This was a phase III, randomised, double-blind multicentre study. Patients were randomised to receive keverprazan 20 mg once daily or lansoprazole 30 mg once daily for 4-8 weeks. EO healing rates and adverse events (AEs) were compared between the keverprazan group and the lansoprazole group.

RESULTS

A total of 238 patients comprised the full analysis set (FAS) while 221 patients comprised the per-protocol set (PPS). For FAS analysis, the EO healing rates at week 8 were 95.8% (114/119) and 89.9% (107/119) for keverprazan and lansoprazole respectively. For PPS analysis, the EO healing rates at week 8 were 99.1% (110/111) and 92.7% (102/110) for keverprazan and lansoprazole respectively. Non-inferiority of keverprazan compared with lansoprazole according to EO healing rates at 8 weeks was demonstrated in both FAS (difference: 5.8% [95% CI: -0.6% to 12.3%]; p = 0.081) and PPS (difference: 6.1% [95% CI: 1.1%-11.2%]; p = 0.018) analysis. Drug-related AEs were reported in 34.5% (41/119) patients of the keverprazan group and 25.2% (30/119) patients of the lansoprazole group with no significant difference (p = 0.156). No severe AE happened in the keverprazan group.

CONCLUSIONS

This study demonstrated the non-inferior efficacy of keverprazan to lansoprazole in treating EO. The incidences of drug-related AEs were comparable between keverprazan and lansoprazole.

Evaluation of the effects of the systemic proton pump inhibitor-omeprazole on periimplant bone regeneration and osseointegration: An experimental study

Objective

Investigations of the effects of proton pump inhibitors (PPIs) on bone healing have revealed that they affect bone regeneration negatively. The exact mechanism by which this adverse effect on bone tissue is not known. The aim of this study is to biomechanic and biochemical investigation of the effects of the PPIs on guided periimplant bone regeneration.

Material & methods

Spraque dawley rats were divided controls (n = 8): there is no treatment during 8 week experimental period, PPI- Dosage 1 (n = 8) and Dosage 2 (n = 8): 5 mg/kg and 10 mg/kg omeprazol applied 3 times in a week with oral gavage during 8 weeks respectfully. Bone defects created half of the implant length circumferencial after implant insertion and defects filled with bone grafts. After experimental period the rats sacrified and implants with surrounding bone tissues were removed to reverse torque analysis (Newton), blood samples collected to biochemical analysis (glucose, AST, ALT, ALP, urea, creatinin, calcium, P).

Results

Biomechanic reverse torque values did not revealed any statistical differences between the groups (P > 0,05).

Conclusion

According the biomechanical and biochemical parameters PPIs does not effect the periimplant guided bone regeneration.

An update of pharmacology, efficacy, and safety of vonoprazan in acid-related disorders

INTRODUCTION

Patients with acid-related disorders (ARDs) of the upper digestive tract remain highly prevalent and need to be continuously investigated to improve their management.

AREAS COVERED

This review provides a summary of the most recent advancements in the treatment of ARDs with particular focus on the new drugs available to overcome the unmet needs of traditional therapies.

EXPERT OPINION

Proton pump inhibitors remain the best therapy in treating ARDs, but a consistent proportion of these patients continues to present mucosal lesions or to experience symptoms despite treatment. These cases pertain mainly to the most severe forms of erosive esophagitis or to non-erosive reflux disease. Also, the increasing rate of patients with H. pylori infection not responding to eradication therapy represents a difficult clinical condition. The recent advent of a new class of antisecretory drugs, such as the potassium competitive acid blockers and, among them the most studied vonoprazan, which are characterized by a better pharmacological profile than PPIs (rapid onset of action, longer lasting acid suppression, control of nocturnal acidity), has the potential to overcome the above-mentioned unmet needs. More research should be done to assess their efficacy in Western populations and their safety in patients treated in the long term.

Application of Analytical Tools and Techniques for Estimation of a Proton Pump Inhibitor (Esomeprazole Magnesium Trihydrate): A Comprehensive Review

Objective:

The application of various sophisticated analytical tools and techniques is essential for estimating an active pharmaceutical ingredient present in either biofluids or pharmaceutical dosage forms. Reporting the multiple analytical methods used to quantify esomeprazole magnesium trihydrate, a proton pump inhibitor, is the ultimate goal of this review article.

Evidence acquisition:

This article deals with a detailed discussion of different reported analytical procedures along with their pros and cons and their relevant criteria for quantifying the drug. Various analytical techniques like UV-Visible spectrophotometry, HPLC, HPTLC, hyphenated techniques, etc., are developed to assess the esomeprazole magnesium trihydrate in bulk materials, different pharmaceutical formulations, and biological matrices.

Conclusion:

Literature survey confirmed that the hyphenated techniques and chromatographic techniques are best tools for biological matrices. Spectroscopic methods like UV and visible techniques are widely used for pharmaceutical matrices. All of the reported methods are accurate, precise, cost-effective, and sensitive.

Safety, Tolerability and Pharmacokinetics of Single Ascending and Multiple Oral Doses of Tegoprazan in Healthy Chinese Subjects

BACKGROUND AND OBJECTIVES

Tegoprazan is one of the potassium-competitive acid blockers (P-CABs). It exhibits its anti-secretory effects by competitively and reversibly blocking the availability of K⁺ of the H⁺, K⁺-ATPase. This study was designed to investigate the safety and pharmacokinetics of tegoprazan in healthy Chinese subjects.

METHODS

Thirty-eight healthy Chinese subjects were recruited in this randomized, single-center, double-blind, placebo-controlled study, with a single ascending dose of 50, 100, 200 mg and a multiple dose of 100 mg for 10 days. The plasma concentration of tegoprazan was determined by a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Pharmacokinetics were evaluated via non-compartmental and compartmental model analysis. Safety was assessed by physical examinations, vital signs, clinical laboratory tests, and electrocardiograms.

RESULTS

No serious adverse event was observed in this study. After single-dose administration (50, 100 and 200 mg), tegoprazan was rapidly absorbed with a median maximum measure plasma concentration (T_max) at 0.5 h and declined with a terminal (elimination) half-life (t_1/2) of 3.87-4.57 h. The maximum measured plasma concentration (C_max) for tegoprazan was 813.80, 1494.60 and 2829.00 ng/mL. Meanwhile, the corresponding area under the concentration-time curve (AUC) from time zero to infinity (AUC_0-inf) was 2761.00, 5980.05 and 11,044.72 ng∙h/mL in 50, 100, 200 mg group, respectively. Dose-dependent increase was observed in the value of C_max and AUC after administration of tegoprazan 50 to 200 mg. The two-compartment model well described the pharmacokinetic profile of tegoprazan. In the steady state, no accumulation was found after repeated administration at the 100-mg dose level. No experimental differences were found based on gender.

CONCLUSIONS

Tegoprazan was well tolerated in the dose range of 50-200 mg in single- and 100 mg in multiple-dose studies. Tegoprazan shows dose linearity with oral administration after a single dose of 50 to 200 mg and less drug accumulation after 10 days of continuous administration in 100 mg.

Analysis of the symptom response to esomeprazole 20 mg over days 1-4 of a 14-day course of treatment for frequent heartburn: results of two randomised controlled trials

BACKGROUND

Drug exposure and corresponding antisecretory effects increase over the first 4-5 days of esomeprazole treatment. To date, this effect has not been correlated with symptomatic improvement. Therefore, the efficacy of esomeprazole was evaluated on days 1-4 and 5-14 using pooled data from two identical randomised, double-blind, placebo-controlled studies conducted in subjects with frequent heartburn who are likely to self-treat with over-the-counter medications.

METHODS

Adults without confirmed diagnoses of gastro-oesophageal reflux disease experiencing heartburn 2 or more days per week in the past 4 weeks were randomly assigned to treatment with esomeprazole 20 mg or placebo once daily for 14 days following a 1-week placebo run-in period (esomeprazole: n=330; placebo: n=321). Heartburn episodes were documented in daily diaries. The current analyses evaluated the change in baseline percentage of heartburn-free days across days 1-4 and 5-14.

RESULTS

Change in the percentage of heartburn-free days from the run-in was significantly greater with esomeprazole compared with placebo (p<0.001) starting on days 1-4. The greatest treatment benefit was observed during days 5-14. During this period, esomeprazole-treated subjects increased their heartburn-free time over the run-in period by 32.5% compared with 14.3% with placebo (p<0.001).

CONCLUSIONS

Frequent heartburn sufferers treated with esomeprazole 20 mg had significantly more heartburn-free days relative to placebo throughout the studies. Maximal clinical benefits coincided with the estimated timing of maximal pharmacokinetic and pharmacodynamic effects and duration of acid control on days 5-14.

TRIAL REGISTRATION NUMBER

NCT01370525; NCT01370538.

The impact of proton pump inhibitors on bone regeneration and implant osseointegration

Proton pump inhibitors (PPIs) have become known for the treatment of gastric-acid related disorders. Similar to any other drugs, PPIs have possible adverse reactions, being associated with bone fractures, infections, kidney disease, mineral deficiency, dementia, and pneumonia. Multiple analyses have stated that PPIs therapy may affect bone regeneration and osseointegration process, causing an increased risk of bone fracture, deterioration of bone metabolism and impaired bone healing. In this review, we emphasized the current literature regarding the influence of proton pump inhibitors in the bone regeneration process. Results from the studies suggest a link between PPIs intake and bone regeneration, but several concerns are raised regarding inadequate recipient bone, surgical trauma, limitations on the titanium surface, comorbidities or interference with other pharmacological agents. Further studies are needed to determine whether the impaired bone regeneration process is due to PPI or coexisting factors.

Cytochrome P450 genotype-guided drug therapies: An update on current states

Over the past 2 decades, knowledge of the role and clinical value of pharmacogenetic markers has expanded so that individualized pre-emptive therapy based on genetic background of patients could be within reach for clinical implementation. This is evidenced from the frequent updating of drug labels that incorporates pharmacogenetic information (where compelling data become available) by the regulatory agencies (such as the US FDA), and the periodical publication of guidelines of specific therapeutic recommendations based on the results of pharmacogenetic tests by the pharmacogenetics working groups or consortiums of professional bodies. Clinical relevance of the cytochrome P450 (CYP) polymorphism related to dose, effectiveness and/or toxicity of key drugs are presented in this review, including that of warfarin, clopidogrel, tricyclic antidepressants, and proton pump inhibitors. Prospect for routine clinical application of CYP genotyping before prescribing drugs is still currently unclear due to challenges and barriers associated with availability of well-defined and validated pharmacogenetic studies, the interpretation, result reporting and potential error of genotype testing, involvement of non-genetic factors, and other patient's demographic and disease conditions. Further studies to provide additional supporting clinical data and acceleration of pharmacogenetic testing standards and techniques should help improve the evidence base needed for clinical utility and hence move the implementation of genotype-guided therapy in clinical practice a step closer to reality.

Risk of small intestinal bacterial overgrowth in patients receiving proton pump inhibitors versus proton pump inhibitors plus prokinetics

Background and Aim

Intestinal dysmotility is considered a risk factor for small intestinal bacterial overgrowth (SIBO). Prokinetics improve intestinal motility and are often prescribed with proton pump inhibitors (PPIs) in patients with gastroesophageal reflux disease (GERD) and/or functional dyspepsia. The present study aimed to evaluate the prevalence of SIBO and the orocecal transit time (OCTT) in patients taking PPI compared with those taking PPI plus prokinetics.

Methods

The study is a single‐center, cross‐sectional study. Enrolled patients (with age > 12 years) were divided into two groups: patients taking PPIs for more than 3 months (Group A) and those taking PPIs with prokinetics for more than 3 months (Group B) for various indications. Lactulose breath test (LBT) for OCTT and glucose breath test (GBT) for SIBO were conducted for all patients.

Results

Of the 147 enrolled patients, SIBO was documented in 13.2% patients in Group A versus 1.8% in Group B, P = 0.018. Median OCTT in Group A was 130 (105–160) min compared with 120 (92.5–147.5) min in Group B (P = 0.010). Median OCTT among SIBO‐positive patients was 160 (140–172.5) min compared with SIBO‐negative patients, where it was 120 (103.75–150) min (P = 0.002). The duration and type of PPI used were not associated with the occurrence of SIBO in our study.

Conclusion

The use of prokinetics in patients on PPI may reduce the risk of SIBO by enhancing intestinal motility and may reduce SIBO risk associated with long‐term PPI use.

Proton pump inhibitors and the risk of severe cognitive impairment: The role of posttraumatic stress disorder

Introduction

Proton pump inhibitors (PPIs), a common treatment for gastroesophageal reflux disease (GERD), were recently associated with increased risk of dementia. However, severe or chronic stress including, for example, posttraumatic stress disorder (PTSD) was not accounted for. This study examined whether PPI use was associated with severe cognitive impairment (SCI) and whether PTSD explained this association in a cohort of World Trade Center (WTC) responders.

Method

A prospective cohort study of 3779 WTC responders attending a university-based monitoring and treatment program. Prescriptions for PPIs and SCI determined using the Montreal Cognitive Assessment were the focus of the analysis.

Results

Overall, 1451 (38.4%) responders were dispensed PPIs, and 83 (2.2%) had SCI. Bivariable analyses revealed significant associations between being-dispensed PPIs in relation to SCI. After adjusting for PTSD, major depressive disorder, WTC exposures, age, and sex, being-dispensed PPIs were significantly associated with odds of SCI (adjusted odds ratio = 1.67 95% confidence interval = 1.054–2.643).

Conclusions

Being-dispensed PPIs were associated with SCI in this analysis of WTC responders. Results suggest that clinicians treating GERD seek to both understand patients' mental health history and monitor cognitive functioning when designing treatment routines. Overall, results confirmed that this is an important area of investigation with potential direct clinical implications.

Acid-Suppressive Therapy and Risk of Infections: Pros and Cons

This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.

In Vitro Evaluation of Nasogastric Tube Delivery Performance of Esomeprazole Magnesium Delayed-Release Capsules

Enteral feeding tubes are used to deliver food or drugs to patients who cannot swallow. To deliver delayed-release drugs that are formulated as enteric coated granules to these patients via feeding tubes requires that they be suspended in water before administration. Importantly, the suspension of enteric granules in water of varying pH can cause damage to the enteric coating and affect the bioavailability of the drug. Here, analytical methods for testing acid resistance stability and particle size distribution (PSD) of esomeprazole granules were used to monitor the integrity of the granule enteric coating after water pretreatment and delivery through an oral syringe and nasogastric (NG) tube. Granules from esomeprazole magnesium delayed-release capsules were transferred to an oral syringe, suspended in water, and delivered on the bench through an NG tube. Subsequently, acid resistance stability (i.e., the amount of drug released after 2-h acid dissolution) was determined via high-performance liquid chromatography, and the PSD were measured with a laser diffraction system. All the granules demonstrated acid resistance stability when the granules were delivered immediately (0 min incubation) through the oral syringe and NG tube. In contrast, some granules demonstrated significant drug release during acid exposure after a 15-min incubation period which mimics a possible delay in delivery of the drug from the syringe by the caregiver. A bimodal PSD was observed with these granules, which was attributed to debris from damaged enteric coating and particle agglomeration. The methods developed in this study could be used to distinguish batches with suboptimal product quality for delivery using NG tubes and to confirm the substitutability of generic drug products for this alternative route of administration.

Vonoprazan is superior to proton pump inhibitors in healing artificial ulcers of the stomach post-endoscopic submucosal dissection: A propensity score-matching analysis

BACKGROUND AND AIM

Proton pump inhibitors (PPI) are effective at healing artificial ulcers after endoscopic submucosal dissection (ESD) for gastric neoplasms; however, the efficacy of vonoprazan is not completely understood. The aim of the present study was to determine the healing effect of vonoprazan on artificial ulcers post-gastric ESD relative to PPI.

METHODS

Thirty-five patients who underwent gastric ESD between April and November 2015 were treated with vonoprazan 20 mg/day for 4 weeks and subsequently underwent endoscopy for evaluation of ulcer size (V group). Ulcer contraction rate was determined by the following formula: ([ESD specimen size] - [ulcer size at 4 weeks after ESD])/(ESD specimen size) × 100%. We compared the results with those of a historical control group treated with esomeprazole 20 mg/day for 4 weeks after gastric ESD and subsequently measured their ulcer size (33 patients, E group) by propensity score-matching methods.

RESULTS

Sixty-two subjects were enrolled after propensity score-matching. Ulcer contraction rate at 4 weeks after ESD in the V group was significantly higher than that of the E group (97.7 ± 3.2% vs 94.5 ± 6.7%, respectively, P = 0.025). Number of subjects with a scar-stage ulcer (100% contraction rate) tended to be higher in the V group relative to the E group (32% [10 of 31] vs 13% [4 of 31], respectively, P = 0.070, McNemar's chi-squared test).

CONCLUSION

Vonoprazan has a faster post-gastric ESD artificial ulcer contraction rate than esomeprazole. Vonoprazan may supersede PPI in treating post-ESD artificial ulcers of the stomach.

Effects of bile acids on human airway epithelial cells: implications for aerodigestive diseases

Gastro-oesophageal reflux and aspiration have been associated with chronic and end-stage lung disease and with allograft injury following lung transplantation. This raises the possibility that bile acids may cause lung injury by damaging airway epithelium. The aim of this study was to investigate the effect of bile acid challenge using the immortalised human bronchial epithelial cell line (BEAS-2B). The immortalised human bronchial epithelial cell line (BEAS-2B) was cultured. A 48-h challenge evaluated the effect of individual primary and secondary bile acids. Post-challenge concentrations of interleukin (IL)-8, IL-6 and granulocyte-macrophage colony-stimulating factor were measured using commercial ELISA kits. The viability of the BEAS-2B cells was measured using CellTiter-Blue and MTT assays. Lithocholic acid, deoxycholic acid, chenodeoxycholic acid and cholic acid were successfully used to stimulate cultured BEAS-2B cells at different concentrations. A concentration of lithocholic acid above 10 μmol·L-1 causes cell death, whereas deoxycholic acid, chenodeoxycholic acid and cholic acid above 30 μmol·L-1 was required for cell death. Challenge with bile acids at physiological levels also led to a significant increase in the release of IL-8 and IL6 from BEAS-2B. Aspiration of bile acids could potentially cause cell damage, cell death and inflammation in vivo. This is relevant to an integrated gastrointestinal and lung physiological paradigm of chronic lung disease, where reflux and aspiration are described in both chronic lung diseases and allograft injury.

The First-in-Class Potassium-Competitive Acid Blocker, Vonoprazan Fumarate: Pharmacokinetic and Pharmacodynamic Considerations

Vonoprazan fumarate (Takecab) is a first-in-class potassium-competitive acid blocker that has been available in the market in Japan since February 2015. Vonoprazan is administered orally at 20 mg once daily for the treatment of gastroduodenal ulcer, at 20 and 10 mg once daily for the treatment and secondary prevention of reflux esophagitis, respectively, at 10 mg once daily for the secondary prevention of low-dose aspirin- or non-steroidal anti-inflammatory drug-induced peptic ulcer, and at 20 mg twice daily in combination with clarithromycin and amoxicillin for the eradication of Helicobacter pylori. It inhibits H(+),K(+)-ATPase activities in a reversible and potassium-competitive manner with a potency of inhibition approximately 350 times higher than the proton pump inhibitor, lansoprazole. Vonoprazan is absorbed rapidly and reaches maximum plasma concentration at 1.5-2.0 h after oral administration. Food has minimal effect on its intestinal absorption. Oral bioavailability in humans remains unknown. The plasma protein binding of vonoprazan is 80% in healthy subjects. It distributes extensively into tissues with a mean apparent volume of distribution of 1050 L. Being a base with pKa of 9.6 and with acid-resistant properties, vonoprazan is highly concentrated in the acidic canaliculi of the gastric parietal cells and elicited an acid suppression effect for longer than 24 h after the administration of 20 mg. The mean apparent terminal half-life of the drug is approximately 7.7 h in healthy adults. Vonoprazan is metabolized to inactive metabolites mainly by cytochrome P450 (CYP)3A4 and to some extent by CYP2B6, CYP2C19, CYP2D6, and SULT2A1. A mass balance study showed that 59 and 8% of the orally administered radioactivity was recovered in urine as metabolites and in an unchanged form, respectively, indicating extensive metabolism. Genetic polymorphism of CYP2C19 may influence drug exposure but only to a clinically insignificant extent (15-29%), according to the population pharmacokinetic study performed in Japanese patients. When vonoprazan was co-administered with clarithromycin, the mean AUC from time 0 to time of the next dose (dosing interval) of vonoprazan and clarithromycin were increased by 1.8 and 1.5 times, respectively, compared with the corresponding control values, indicating mutual metabolic inhibition. The mean area under the curve from time zero to infinity obtained from patients with severe liver and renal dysfunction were elevated by 2.6 and 2.4 times, respectively, compared with healthy subjects, with no significant changes in plasma protein binding. Vonoprazan increases intragastric pH above 4.0 as early as 4 h after an oral dose of 20 mg, and the extensive anti-secretory effect is maintained up to 24 h post-dose. During repeated dosing of 20 mg once daily, the 24-h intragastric pH >4 holding time ratios were 63 and 83 % on days 1 and 7, respectively. Because vonoprazan elicited a more extensive gastric acid suppression than the proton pump inhibitor, lansoprazole, it also gave rise to two to three times greater serum gastrin concentrations as compared with lansoprazole. In pre-approval clinical studies for the treatment of acid-related disorders, mild to moderate adverse drug reactions (mostly constipation or diarrhea) occurred at frequencies of 8-17%. Neither severe liver toxicity nor neuroendocrine tumor has been reported in patients receiving vonoprazan.

Effects of ischemia and omeprazole preconditioning on functional recovery of isolated rat heart

OBJECTIVE

The aim of this study was to compare protective effects of ischemic and potential protective effects of pharmacological preconditioning with omeprazole on isolated rat heart subjected to ischemia/reperfusion.

METHODS

The hearts of male Wistar albino rats were excised and perfused on a Langendorff apparatus. In control group (CG) after stabilization period, hearts were subjected to global ischemia (perfusion was totally stopped) for 20 minutes and 30 minutes of reperfusion. Hearts of group II (IPC) were submitted to ischemic preconditioning lasting 5 minutes before 20 minutes of ischemia and 30 minutes of reperfusion. In third group (OPC) hearts first underwent preconditioning lasting 5 minutes with 100 μM omeprazole, and then submitted 20 minutes of ischemia and 30 minutes of reperfusion.

RESULTS

Administration of omeprazole before ischemia induction had protective effect on myocardium function recovery especially regarding to values of systolic left ventricular pressure and dp/dt max. Also our findings are that values of coronary flow did not change between OPC and IPC groups in last point of reperfusion.

CONCLUSION

Based on our results it seems that ischemic preconditioning could be used as first window of protection after ischemic injury especially because all investigated parameters showed continuous trend of recovery of myocardial function. On the other hand, preconditioning with omeprazole induced sudden trend of recovery with positive myocardium protection, although less effective than results obtained with ischemic preconditioning not withstand, we must consider that omeprazole may be used in many clinical circumstances where direct coronary clamping for ischemic preconditioning is not possible.

Multi-indication Pharmacotherapeutic Multicriteria Decision Analytic Model for the Comparative Formulary Inclusion of Proton Pump Inhibitors in Qatar

PURPOSE

The formulary inclusion of proton pump inhibitors (PPIs) in the government hospital health services in Qatar is not comparative or restricted. Requests to include a PPI in the formulary are typically accepted if evidence of efficacy and tolerability is presented. There are no literature reports of a PPI scoring model that is based on comparatively weighted multiple indications and no reports of PPI selection in Qatar or the Middle East. This study aims to compare first-line use of the PPIs that exist in Qatar. The economic effect of the study recommendations was also quantified.

METHODS

A comparative, evidence-based multicriteria decision analysis (MCDA) model was constructed to follow the multiple indications and pharmacotherapeutic criteria of PPIs. Literature and an expert panel informed the selection criteria of PPIs. Input from the relevant local clinician population steered the relative weighting of selection criteria. Comparatively scored PPIs, exceeding a defined score threshold, were recommended for selection.

FINDINGS

Weighted model scores were successfully developed, with 95% CI and 5% margin of error. The model comprised 7 main criteria and 38 subcriteria. Main criteria are indication, dosage frequency, treatment duration, best published evidence, available formulations, drug interactions, and pharmacokinetic and pharmacodynamic properties. Most weight was achieved for the indications selection criteria. Esomeprazole and rabeprazole were suggested as formulary options, followed by lansoprazole for nonformulary use. The estimated effect of the study recommendations was up to a 15.3% reduction in the annual PPI expenditure. Robustness of study conclusions against variabilities in study inputs was confirmed via sensitivity analyses.

IMPLICATIONS

The implementation of a locally developed PPI-specific comparative MCDA scoring model, which is multiweighted indication and criteria based, into the Qatari formulary selection practices is a successful evidence-based cost-cutting exercise. Esomeprazole and rabeprazole should be the first-line choice from among the PPIs available at the Qatari government hospital health services.

CYP2C19 polymorphism influences Helicobacter pylori eradication

The known factors that have contributed to the decline of Helicobacter pylori (H. pylori) eradication rate include antibiotic resistance, poor compliance, high gastric acidity, high bacterial load, and cytochrome P450 2C19 (CYP2C19) polymorphism. Proton pump inhibitor (PPI) is important in the eradication regimen. The principal enzyme implicated in the metabolism of PPIs is CYP2C19. The effects of PPI depend on metabolic enzyme, cytochrome P450 enzymes, and CYP2C19 with genetic differences in the activity of this enzyme (the homozygous EM, heterozygous EM (HetEM), and poor metabolizer). The frequency of the CYP2C19 polymorphism is highly varied among different ethnic populations. The CYP2C19 genotype is a cardinal factor of H. pylori eradication in patients taking omeprazole- based or lansoprazole-based triple therapies. In contrast, the CYP2C19 polymorphism has no significant effect on the rabeprazole-based or esomeprazole-based triple therapies. The efficacy of levofloxacin-based rescue triple therapy might be also affected by the CYP2C19 polymorphism, but CYP2C19 genotypes did not show obvious impact on other levofloxacin-based rescue therapies. Choice of different PPIs and/or increasing doses of PPIs should be individualized based on the pharmacogenetics background of each patient and pharmacological profile of each drug. Other possible factors influencing gastric acid secretion (e.g., IL-1β- 511 polymorphism) would be also under consideration.

A new mechanism of action of thienopyridine antiplatelet drugs - a role for gastric nitrosthiol metabolism?

This article outlines a new hypothesis that illustrates the potential role of the stomach (and subsequent chemical reactions involving nitrite therein) in modifying thienopyridines, such as clopidogrel. Gastric modification of thienopyridines can occur before standard accepted biotransformation pathways ensue. We hypothesised that thienopyridines expose the free thiol group once acidified (by the stomach) before biotransformation into active metabolites, and in the presence of nitrite (from saliva and the stomach) to form nitrosothiol derivatives (Thienopyridine induced-SNO formation). We have performed in vitro studies with each of the thienopyridines tablets/compounds confirming direct Th-SNO formation from the parent (inactive) drug by the following mechanism. Thienopyridine-SH + H(+ (Stomach)) +  [Formula: see text] ↔ Thienopyridine-SNO + H2O Thienopyridine-SNO (an S-nitrosothiol molecule) would have the potential to participate in all the reactions expected of native nitric oxide (NO) with added benefit that the NO "moiety" is protected, transportable and largely preserved from further reactive metabolism. All these biochemical steps are present in humans and could occur prior to enzymatic biotransformation.

Acid peptic diseases: pharmacological approach to treatment

Acid peptic disorders are the result of distinctive, but overlapping pathogenic mechanisms leading to either excessive acid secretion or diminished mucosal defense. They are common entities present in daily clinical practice that, owing to their chronicity, represent a significant cost to healthcare. Key elements in the success of controlling these entities have been the development of potent and safe drugs based on physiological targets. The histamine-2 receptor antagonists revolutionized the treatment of acid peptic disorders owing to their safety and efficacy profile. The proton-pump inhibitors (PPIs) represent a further therapeutic advance due to more potent inhibition of acid secretion. Ample data from clinical trials and observational experience have confirmed the utility of these agents in the treatment of acid peptic diseases, with differential efficacy and safety characteristics between and within drug classes. Paradigms in their speed and duration of action have underscored the need for new chemical entities that, from a single dose, would provide reliable duration of acid control, particularly at night. Moreover, PPIs reduce, but do not eliminate, the risk of ulcers in patients taking NSAIDs, reflecting untargeted physiopathologic pathways and a breach in the ability to sustain an intragastric pH of more than 4. This review provides an assessment of the current understanding of the physiology of acid production, a discussion of medications targeting gastric acid production and a review of efficacy in specific acid peptic diseases, as well as current challenges and future directions in the treatment of acid-mediated diseases.

The pharmacokinetics of ilaprazole for gastro-esophageal reflux treatment

INTRODUCTION

Approximately 20% of the Western population is affected by gastro-esophageal reflux disease (GERD). To date, proton pump inhibitors (PPIs) represent the mainstay of GERD medical treatment. However, despite their undoubted benefit, about 40% of GERD patients display an inadequate response to these drugs. Recently, a new PPI, ilaprazole , at oral doses of 10 mg has shown higher suppression of gastric acid secretion, more prolonged plasma half-life, and similar safety compared to 20 mg omeprazole.

AREAS COVERED

This review provides an update on the following points: pharmacokinetic profile and metabolism of ilaprazole in relation to its pharmacodynamic properties; comparative data on the pharmacokinetics and pharmacodynamics of ilaprazole with currently available PPIs; and implications for studies on the therapeutic efficacy of ilaprazole in GERD.

EXPERT OPINION

Different studies show that ilaprazole, a benzimidazole derivative, has an extended plasma half-life in comparison with all other approved PPIs. In addition, ilaprazole metabolism is not significantly influenced by CYP2C19, compared to the available PPIs. Furthermore, the pharmacological characteristics of ilaprazole confer theoretical advantages that are expected to translate into an improved acid control, particularly at night time. However, studies comparing the clinical pharmacokinetics and pharmacodynamics of ilaprazole with those of second-generation PPIs are insufficient. Moreover, further investigations assessing the efficacy of ilaprazole in the management of GERD are required. In healthy volunteers, as well as in patients with gastric or duodenal ulcers, ilaprazole has not shown clinically relevant changes in hematology and biochemistry testing, nor significant treatment-related adverse symptoms.

Applications of CYP450 testing in the clinical setting

Interindividual variability in drug response is a major clinical problem. Polymedication and genetic polymorphisms modulating drug-metabolising enzyme activities (cytochromes P450, CYP) are identified sources of variability in drug responses. We present here the relevant data on the clinical impact of the major CYP polymorphisms (CYP2D6, CYP2C19 and CYP2C9) on drug therapy where genotyping and phenotyping may be considered, and the guidelines developed when available. CYP2D6 is responsible for the oxidative metabolism of up to 25% of commonly prescribed drugs such as antidepressants, antipsychotics, opioids, antiarrythmics and tamoxifen. The ultrarapid metaboliser (UM) phenotype is recognised as a cause of therapeutic inefficacy of antidepressant, whereas an increased risk of toxicity has been reported in poor metabolisers (PMs) with several psychotropics (desipramine, venlafaxine, amitriptyline, haloperidol). CYP2D6 polymorphism influences the analgesic response to prodrug opioids (codeine, tramadol and oxycodone). In PMs for CYP2D6, reduced analgesic effects have been observed, whereas in UMs cases of life-threatening toxicity have been reported with tramadol and codeine. CYP2D6 PM phenotype has been associated with an increased risk of toxicity of metoprolol, timolol, carvedilol and propafenone. Although conflicting results have been reported regarding the association between CYP2D6 genotype and tamoxifen effects, CYP2D6 genotyping may be useful in selecting adjuvant hormonal therapy in postmenopausal women. CYP2C19 is responsible for metabolising clopidogrel, proton pump inhibitors (PPIs) and some antidepressants. Carriers of CYP2C19 variant alleles exhibit a reduced capacity to produce the active metabolite of clopidogrel, and are at increased risk of adverse cardiovascular events. For PPIs, it has been shown that the mean intragastric pH values and the Helicobacter pylori eradication rates were higher in carriers of CYP2C19 variant alleles. CYP2C19 is involved in the metabolism of several antidepressants. As a result of an increased risk of adverse effects in CYP2C19 PMs, dose reductions are recommended for some agents (imipramine, sertraline). CYP2C9 is responsible for metabolising vitamin K antagonists (VKAs), non-steroidal anti-inflammatory drugs (NSAIDs), sulfonylureas, angiotensin II receptor antagonists and phenytoin. For VKAs, CYP2C9 polymorphism has been associated with lower doses, longer time to reach treatment stability and higher frequencies of supratherapeutic international normalised ratios (INRs). Prescribing algorithms are available in order to adapt dosing to genotype. Although the existing data are controversial, some studies have suggested an increased risk of NSAID-associated gastrointestinal bleeding in carriers of CYP2C9 variant alleles. A relationship between CYP2C9 polymorphisms and the pharmacokinetics of sulfonylureas and angiotensin II receptor antagonists has also been observed. The clinical impact in terms of hypoglycaemia and blood pressure was, however, modest. Finally, homozygous and heterozygous carriers of CYP2C9 variant alleles require lower doses of phenytoin to reach therapeutic plasma concentrations, and are at increased risk of toxicity. New diagnostic techniques made safer and easier should allow quicker diagnosis of metabolic variations. Genotyping and phenotyping may therefore be considered where dosing guidelines according to CYP genotype have been published, and help identify the right molecule for the right patient.

Rabeprazole for the treatment of acid-related disorders

Proton pump inhibitors are widely used for the treatment of acid-related disorders. Rabeprazole is a potent and irreversible inhibitor of H(+)/K(+)-ATPase gastric pump, and it is indicated for the treatment of gastroesophageal reflux disease, Zollinger Ellison syndrome, duodenal and gastric ulcers and for the eradication of Helicobacter pylori in combination with antibiotics. Pharmacokinetic and pharmacodynamic data show that rabeprazole achieves a pronounced acid suppression from the first administration that is maintained with repeated use; this may translate into faster onset of symptom relief for patients, particularly suitable when the indication is for the on-demand long-term maintenance of gastroesophageal reflux disease. Due to its predominantly nonenzymatic metabolism, rabeprazole has a lower potential for drug-drug interactions. The objective of this article is to update efficacy and safety data of rabeprazole in the treatment of acid-related disorders, following a previous review dated 2008.

Clopidogrel and proton pump inhibitors - where do we stand in 2012?

Clopidogrel in association with aspirine is considered state of the art of medical treatment for acute coronary syndrome by reducing the risk of new ischemic events. Concomitant treatment with proton pump inhibitors in order to prevent gastrointestinal side effects is recommended by clinical guidelines. Clopidogrel needs metabolic activation predominantly by the hepatic cytochrome P450 isoenzyme Cytochrome 2C19 (CYP2C19) and proton pump inhibitors (PPIs) are extensively metabolized by the CYP2C19 isoenzyme as well. Several pharmacodynamic studies investigating a potential clopidogrel-PPI interaction found a significant decrease of the clopidogrel platelet antiaggregation effect for omeprazole, but not for pantoprazole. Initial clinical cohort studies in 2009 reported an increased risk for adverse cardiovascular events, when under clopidogrel and PPI treatment at the same time. These observations led the United States Food and Drug Administration and the European Medecines Agency to discourage the combination of clopidogrel and PPI (especially omeprazole) in the same year. In contrast, more recent retrospective cohort studies including propensity score matching and the only existing randomized trial have not shown any difference concerning adverse cardiovascular events when concomitantly on clopidogrel and PPI or only on clopidogrel. Three meta-analyses report an inverse correlation between clopidogrel-PPI interaction and study quality, with high and moderate quality studies not reporting any association, rising concern about unmeasured confounders biasing the low quality studies. Thus, no definite evidence exists for an effect on mortality. Because PPI induced risk reduction clearly overweighs the possible adverse cardiovascular risk in patients with high risk of gastrointestinal bleeding, combination of clopidogrel with the less CYP2C19 inhibiting pantoprazole should be recommended.

New look at antiplatelet agent-related peptic ulcer: an update of prevention and treatment

Patients taking antiplatelet agents for the prevention of cardiovascular diseases who develop gastrointestinal bleeding represent a serious challenge in clinical practice. The initial step in reducing gastrointestinal risk of antiplatelet therapy is to assess whether the patient has a continued need for antiplatelet therapy. The next step is to eliminate the risk factors that may place the patient at increased gastrointestinal risk. In the management of bleeding ulcer patients with high-risk stigmata of recent hemorrhage, resuming antiplatelet agents at 3-5 days after the last dosing is a reasonable strategy. However, patients with low-risk stigmata can keep taking antiplatelet agents immediately following endoscopy. In the management of aspirin-related uncomplicated peptic ulcers in patients requiring antiplatelet therapies, continuing aspirin plus a powerful proton pump inhibitor is the choice of treatment. Patients who require antiplatelet agents for the prevention of cardiovascular diseases should be tested and treated for Helicobacter pylori infection before starting antiplatelet therapy. Additionally, those with high risks for upper gastrointestinal bleeding should receive co-therapy with a gastroprotective drug, preferably a proton pump inhibitor at standard dose. H2-receptor antagonist can significantly reduce upper gastrointestinal bleeding risk in patients taking low-dose aspirin but it is ineffective in the prevention of upper gastrointestinal bleeding in clopidogrel users. Although several retrospective studies reported that patients prescribed clopidogrel who also took proton pump inhibitors had significant increases in cardiovascular events, the current evidence from a prospective randomized trial does not justify a conclusion that proton pump inhibitors are associated with cardiovascular events among clopidogrel users.

Acid inhibition effect of ilaprazole on Helicobacter pylori-negative healthy volunteers: an open randomized cross-over study

OBJECTIVE

The aim of this study was to evaluate the effects and safety of different doses of ilaprazole on healthy volunteers without a Helicobacter pylori infection.

METHODS

A total of 12 healthy Chinese volunteers were enrolled and divided into four groups randomly, with a 5-day treatment of oral ilaprazole 5mg, 10mg and 20mg or omeprazole 20mg, respectively. After an interval of a 14-day washout phase, each was switched to another dose group and eventually completed all four regimens. The percentage time of intragastric pH>4 was the major index. The polymorphisms of the metabolic enzyme CYP2C19 in these volunteers were also detected.

RESULTS

The percentage time of intragastric pH>4 in the ilaprazole 5, 10 and 20mg groups were 80.4%, 88.1% and 91.0%, respectively, during the first 24h, compared to that of the 20mg omeprazole group (76.6%, P>0.05). Ilaprazole 20mg provided a significant higher mean 24-h pH than that of the same dose of omeprazole both on Day 1 (7.78 vs 6.67, P<0.01) and Day 5 (7.95 vs 7.44, P<0.05). No CYP2C19-dependent difference or obvious adverse effect were found in any ilaprazole groups.

CONCLUSION

Low dose ilaprazole offers a gastric acid inhibition comparable to a routine dose of omeprazole, and further investigations in patients with acid-associated diseases are needed.

Clinical evidence of interaction between clopidogrel and proton pump inhibitors

Clopidogrel is approved for reduction of atherothrombotic events in patients with cardiovascular (CV) and cerebrovascular disease. Dual antiplatelet therapy with aspirin and clopidogrel decreases the risk of major adverse cardiac events after acute coronary syndrome or percutaneous coronary intervention, compared with aspirin alone. Due to concern about gastrointestinal bleeding in patients who are receiving clopidogrel and aspirin therapy, current guidelines recommend combined use of a proton pump inhibitor (PPI) to decrease the risk of bleeding. Data from previous pharmacological studies have shown that PPIs, which are extensively metabolized by the cytochrome system, may decrease the ADP-induced platelet aggregation of clopidogrel. Results from retrospective cohort studies have shown a higher incidence of major CV events in patients receiving both clopidogrel and PPIs than in those without PPIs. However, other retrospective analyses of randomized clinical trials have not shown that the concomitant PPI administration is associated with increased CV events among clopidogrel users. These controversial results suggest that large specific studies are needed. This article reviews the metabolism of clopidogrel and PPIs, existing clinical data regarding the interaction between clopidogrel and PPIs, and tries to provide recommendations for health care professionals.

Review article: combination of clopidogrel and proton pump inhibitors: implications for clinicians

OBJECTIVES

to evaluate the existing literature on a proposed interaction between clopidogrel and proton pump inhibitors (PPIs) and discuss its implications for clinicians treating patients with this combination therapy.

BACKGROUND

each year millions of patients receive antiplatelet therapy. A number of these patients are prescribed PPIs concomitantly to reduce the risk of gastrointestinal side effects associated with antiplatelet therapy. Several studies have been published recently addressing a potential adverse drug-drug interaction between clopidogrel and PPIs.

METHODS

literature was evaluated through Pubmed using the terms clopidogrel, PPI, prasugrel, cytochrome P450, genetic polymorphisms, H( 2) blockers, famotidine, genetic cytochrome P450 polymorphisms, and drug interaction. Articles with these terms were considered for evaluation. In addition, reference citations from publications identified in the searches were further reviewed and analyzed.

RESULTS

none of the currently published studies were specifically designed to evaluate this drug-drug interaction or address the clinical relevance of this interaction prospectively. Conflicting evidence raised concerns but the information did not conclude with certainty a cause-and-effect relationship between concomitant use of the drugs and emerging safety issues. However, the Food and Drug Administration issued a public-health warning on the possible interaction between clopidogrel and PPIs, predominantly with omeprazole, in November 2009.

CONCLUSIONS

controversies exist on a potential drug-drug interaction between clopidogrel and PPIs. Although further studies are warranted, several studies indicated that there was a drug-drug interaction through this combination therapy with detrimental clinical outcomes and increased costs. Studies suggested that the use of a PPI may make clopidogrel less effective resulting in a higher risk of myocardial infarction, stroke, or death. Until additional information becomes available clinicians should consider discontinuing PPI use if no clear indication is documented. Alternative options like H(2)-receptor antagonists should be considered. Upon availability, genetic testing may provide additional valuable information.

Inhibition of the antithrombotic effects of clopidogrel by proton pump inhibitors: facts or fancies?

Clopidogrel plus aspirin is considered the antiplatelet treatment of choice in patients with acute coronary syndrome, whether or not they are undergoing a percutaneous coronary intervention (PCI). The same treatment is mandatory in all patients undergoing a PCI with stent implantation. Clopidogrel is a pro-drug that needs metabolic activation through a cytochrome P450-dependent pathway, with an extensive involvement of the CYP 2C19 isoenzyme. Proton pump inhibitors (PPIs) reduce the risk of gastrointestinal bleeding in patients receiving dual antiplatelet therapy. In the past two years some scientific evidences have suggested a possible negative interference of PPIs on antiplatelet effect of clopidogrel because of the competitive inhibition of the CYP 2C19 isoenzyme. Few studies testing platelet reactivity in patients receiving both clopidogrel and a PPI have demonstrated a reduced inhibitory effect of the association on platelet aggregation. Moreover, results from retrospective observational studies have shown a higher incidence of major cardiovascular events in patients receiving both clopidogrel and PPIs. These data have not been confirmed neither by the only prospective randomized study comparing clopidogrel plus omeprazole with clopidogrel alone, nor by the retrospective analysis of the TRITON TIMI 38 trial, where PPIs did not affect the clinical outcome of patients given clopidogrel or prasugrel. Nevertheless both the US Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) have discouraged the concomitant use of clopidogrel and PPIs. Important questions concerning a true interference between the two classes of drugs still remain unanswered and need to be addressed by adequately powered studies.

Optimal management of peptic ulcer disease in the elderly

Recent data report that the incidence of peptic ulcer is decreasing in the general population; conversely, the rates of gastric and duodenal ulcer hospitalization and mortality remain very high in older patients. Two major factors that might explain this epidemiological feature in the elderly population are the high prevalence of Helicobacter pylori infection and the increasing prescriptions of gastroduodenal damaging drugs, including NSAIDs and/or aspirin (acetylsalicylic acid). The main goals for treating peptic ulcer disease in old age are to reduce recurrence of the disease and to prevent complications, especially bleeding and perforation. The available treatments for peptic ulcer are essentially based on gastric acid suppression with antisecretory drugs and the eradication of H. pylori infection. The aim of this article is to report the available data on clinical efficacy and tolerability of peptic ulcer treatments in elderly patients and provide recommendations for their optimal use in this special population. Proton pump inhibitor (PPI)-based triple therapies for 7 days are highly effective for the cure of H. pylori-positive peptic ulcers as well as for reducing ulcer recurrence. Antisecretory drugs are also the treatment of choice for NSAID- or aspirin-related peptic ulcers and are useful as preventive therapy in chronic users of NSAIDs and low-dose aspirin as antiplatelet therapy. Antisecretory PPI therapy has a favourable tolerability profile in geriatric patients; however, monitoring is suggested in older patients with frequent pulmonary infections, gastrointestinal malabsorption, unexplained chronic diarrhoea, osteoporosis or those taking concomitant cytochrome P450 2C19-metabolized medications. The overall approach to the geriatric patient should include a comprehensive geriatric assessment that ensures multidimensional evaluation of the patient in order to better define the clinical risk of adverse outcomes in the older patient with peptic ulcer and its complications.

Proton pump inhibitor and clopidogrel interaction: the case for watchful waiting

Clopidogrel is an integral part of the management of several important vascular diseases. However the medium to long term clinical outcomes are poorer for these patients if they experience gastro-intestinal bleeding, hence patients with risk factors for gastro-intestinal bleeding are frequently prescribed proton pump inhibitors. Conflicting evidence exists as to the existence of an adverse interaction between clopidogrel and proton pump. This review examines the original studies, which suggested the adverse interaction, the subsequent and most recent studies, the pharmaco-dynamics of the two drugs and suggests an algorithm for the use of clopidogrel with proton pump inhibitors.