Rabeprazole: the role of proton pump inhibitors inHelicobacter pylorieradication

Exploring Differences in Pharmacometrics of Rabeprazole between Genders via Population Pharmacokinetic-Pharmacodynamic Modeling

Rabeprazole is a proton pump inhibitor that inhibits gastric acid production and increases gastric pH; it is widely used clinically as a treatment option for gastritis and gastric ulcers. However, information on the inter-individual variability of rabeprazole pharmacometrics, which is a key element in establishing its scientific clinical use, is still lacking. Particularly, the differences in pharmacokinetics between genders and the degree of variation in pharmacodynamics have not been clearly identified. Thus, the main purpose of this study was to explore any differences in rabeprazole pharmacokinetics between genders and to quantitatively predict and compare the effects of any differences in pharmacokinetics between genders on known pharmacodynamics using population pharmacokinetic-pharmacodynamic modeling. To compare pharmacokinetics and modeling data between genders, bioequivalence results were used simultaneously on healthy Korean men and women using the physiological and biochemical parameters derived from each individual. Pharmacodynamic modeling was performed based on the data of previously reported gastric pH changes in response to rabeprazole plasma concentrations, which was co-linked to the central compartmental bioavailable concentration in the population pharmacokinetic model. There was no significant difference in the level of rabeprazole exposure and elimination of plasma between genders following oral administration of 10 mg enteric-coated rabeprazole tablets; however, there was a clear delay in absorption in women compared to men. Additionally, a comparison of pharmacokinetic parameters normalized to body weight between genders showed that the maximum plasma concentrations were significantly higher in women than in men, again suggesting gender differences in rabeprazole absorption. The population pharmacokinetic profiles for rabeprazole were described using a three-sequential multi-absorption with lag time (Tlag) two-compartment model, whereas body surface area and gender were explored as effective covariates for absorption rate constant and Tlag, respectively. The effect of increased gastric pH due to plasma exposure to rabeprazole was explained using the Sigmoid Emax model, with the baseline as a direct response. The significantly longer rabeprazole Tlag in females delayed the onset of an effect by an average of 1.58 times (2.02-3.20 h), yet the overall and maximum effects did not cause a significant difference within 15%. In the relative comparison of the overall efficacy of rabeprazole enteric-coated tablet administration between genders, it was predicted based on the model that males would have higher efficacy. This study will be very useful in broadening the perspective of interpreting drug diversity between individuals and narrowing the gap in knowledge related to scientific precision medicine by presenting new information on gender differences in rabeprazole pharmacometrics that had not been previously identified.

An O-Demethylation Metabolite of Rabeprazole Sulfide by Cunninghamella blakesleeana 3.970 Biotransformation

To explore the potential metabolites from rabeprazole sulfide, seven strains of filamentous fungi were screened for their biotransformation abilities. Among these strains, Cunninghamella blakesleeana 3.970 exhibited the best result. Four different culture media were screened in order to identify the most optimal for subsequent research. Single factors such as the initial pH of culture media, culture time, inoculation volume, and media volume were individually investigated to provide the optimum biotransformation conditions. Then, an orthogonal optimization process using a five-factor, four-level L16(45) experiment was designed and performed. Finally, when the substrate concentration is 3 g/L, one major metabolite was detected with a transformation rate of 72.4%. Isolated by semipreparative HPLC, this metabolite was further detected by ESI-MS and NMR. The final data analysis indicated that the metabolite is O-demethylation rabeprazole sulfide.

Rabeprazole-amoxicillin dual therapy as first-line treatment for H pylori eradication in special patients: A retrospective, real-life study

BACKGROUND

The currently recommended quadruple regimens for Helicobacter pylori infection might not be appropriate for every patient, especially in elderly patients or those with multiple comorbidities.

OBJECTIVE

To evaluate the efficacy and safety of rabeprazole-amoxicillin dual therapy in H pylori-positive elderly patients or those with multiple comorbidities.

METHODS

From November 2013 to May 2017, the clinical data of H pylori-positive patients ≥60 years old or with multiple comorbidities were collected and reviewed. All patients were given rabeprazole 10 mg three times a day and amoxicillin 1000 mg thrice a day (RA dual therapy) for 14 days as first-line treatment. H pylori eradication was evaluated by ¹³ C-urea breath test 6 weeks after treatment. Adverse effects were recorded.

RESULTS

A total of 198 patients were enrolled, including 116 elderly patients and 82 patients with multiple comorbidities. Successful eradication was achieved in 90.9% (180/198, 95% CI: 86.1%-94.2%) patients. Adverse effects, which were mainly mild (referring to skin rash, abdominal pain, and diarrhea), occurred in 22 patients (22/198, 11.1%) and resolved spontaneously.

CONCLUSION

Dual therapy composed of rabeprazole and amoxicillin as a first-line treatment appears to be effective and safe for H pylori infection in elderly patients or those with multiple comorbidities. Additional studies are needed to optimize the regimen.

Proton Pump Inhibitor Switching Strategy after Failure of Standard Triple Therapy for Helicobacter pylori Infection

Background/Aims: It is still unknown whether cytochrome P450 (CYP) 2C19 polymorphisms influence <i>Helicobacter pylori</i> (<i>H. pylori</i>) eradication, especially in eastern Asia. We aimed to evaluate how changes in proton pump inhibitor (PPI) strategies could be used to overcome the effects of CYP2C19 polymorphism on <i>H. pylori</i> eradication rate when it is used as the second-line regimen after the failure of standard triple therapy.Materials and Methods: We performed a retrospective observation study of 675 patients in whom standard triple therapy for <i>H. pylori</i> infection was not effective between January 2009 to December 2018. All patients underwent a classic bismuth-containing quadruple therapy (10 to 14-day regimen), and their eradication rates were evaluated for several years. We compared the eradication rates in patients with or without the second-line PPI switch. Further, we assessed differences in eradication rates with or without the strategy using esomeprazole and rabeprazole, which are not influenced significantly by CYP2C19 genetic polymorphism.Results: The eradication rate was 81.0% in individuals who received the second-line PPI switch, but it was 74.8% without switching (<i>P</i>=0.14). In the strategy using esomeprazole and rabeprazole, the eradication rate was 84.6%, compared to 76.5% in the control group (<i>P</i>=0.03). Finally, in the group of patients who switched to rabeprazole, the eradication rates were 85.6%, compared to 77.6% in the group who switched to pantoprazole (<i>P</i>=0.05).Conclusions: Switching to PPI, which is not influenced by CYP2C19 genetic polymorphism, increases the efficiency of eradication after the failure of standard triple therapy.

Helicobacter pylori and low-dose aspirin ulcer risk: A meta-analysis

BACKGROUND AND AIM

Owing to wide-spread use, low-dose aspirin (LDA) produces a substantial amount of peptic ulcer disease. Current guidelines are ambivalent about the need for Helicobacter pylori eradication to protect against LDA ulcers. This study aimed to determine, through meta-analysis, if (and by how much) infection alters the baseline risk of peptic ulcers during LDA therapy.

METHODS

Literature screening was performed in MEDLINE and EMBASE from inception to May 2018. Original studies reporting prevalence or incidence of uncomplicated ulcers in LDA users were included. Ulcer endpoints needed to be specified separately, according to H. pylori infection status. Meta-analysis was performed in MIX 2.0 Pro.

RESULTS

Ten cross-sectional studies and seven randomized controlled trials were included (n = 5964). The pooled odds ratios with 95% confidence intervals (CI) for the risk of LDA ulcers in H. pylori-positive versus H. pylori-negative individuals were 1.68 (95%CI 1.40-2.02) and 1.65 (95%CI 1.29-2.08) under fixed-effects and random-effects models, respectively. Heterogeneity among studies was minimal (I²  = 26.9%). After adjusting for the protective effects of antisecretory drugs, the odds ratios increased to 1.94 (95%CI 1.54-2.46).

CONCLUSION

This analysis suggests that H. pylori increases the risk of LDA ulcers by almost 70% in a population where some were taking proton pump inhibitors and/or other acid suppressants. Without antisecretory drugs, the risk almost doubles. Clinically, these findings may support the use of a test-and-treat approach to H. pylori in LDA users, particularly those already at higher risk of developing peptic ulcers.

The Possible Role of Helicobacter pylori in Gastric Cancer and Its Management

Helicobacter pylori (HP) is a facultative anaerobic bacterium. HP is a normal flora having immuno-modulating properties. This bacterium is an example of a microorganism inducing gastric cancer. Its carcinogenicity depends on bacteria-host related factors. The proper understanding of the biology of HP inducing gastric cancer offers the potential strategy in the managing of HP rather than eradicating it. In this article, we try to summarize the biology of HP-induced gastric cancer and discuss the current pharmacological approach to treat and prevent its carcinogenicity.

Applications for Bacteriophage Therapy during Pregnancy and the Perinatal Period

Pregnant women and their unborn children are a population that is particularly vulnerable to bacterial infection. Physiological changes that occur during pregnancy affect the way women respond to such infections and the options that clinicians have for treatment. Antibiotics are still considered the best option for active infections and a suitable prophylaxis for prevention of potential infections, such as vaginal/rectal Streptococcus agalactiae colonization prior to birth. The effect of such antibiotic use on the developing fetus, however, is still largely unknown. Recent research has suggested that the fetal gut microbiota plays a critical role in fetal immunologic programming. Hence, even minor alterations in this microbiota may have potentially significant downstream effects. An ideal antibacterial therapeutic for administration during pregnancy would be one that is highly specific for its target, leaving the surrounding microbiota intact. This review first provides a basic overview of the challenges a clinician faces when administering therapeutics to a pregnant patient and then goes on to explore common bacterial infections in pregnancy, use of antibiotics for treatment/prevention of such infections and the consequences of such treatment for the mother and infant. With this background established, the review then explores the potential for use of bacteriophage (phage) therapy as an alternative to antibiotics during the antenatal period. Many previous reviews have highlighted the revitalization of and potential for phage therapy for treatment of a range of bacterial infections, particularly in the context of the increasing threat of widespread antibiotic resistance. However, information on the potential for the use of phage therapeutics in pregnancy is lacking. This review aims to provide a thorough overview of studies of this nature and discuss the feasibility of bacteriophage use during pregnancy to treat and/or prevent bacterial infections.

Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report

Important progress has been made in the management of Helicobacter pylori infection and in this fifth edition of the Maastricht Consensus Report, key aspects related to the clinical role of H. pylori were re-evaluated in 2015. In the Maastricht V/Florence Consensus Conference, 43 experts from 24 countries examined new data related to H. pylori in five subdivided workshops: (1) Indications/Associations, (2) Diagnosis, (3) Treatment, (4) Prevention/Public Health, (5) H. pylori and the Gastric Microbiota. The results of the individual workshops were presented to a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in the various clinical scenarios.

Benzimidazoles and benzoxazoles via the nucleophilic addition of anilines to nitroalkanes

PPA-induced umpolung triggers efficient nucleophilic addition of unactivated anilines to nitroalkanes to produce N-hydroxyimidamides. The latter undergo sequential acid-promoted cyclocondensation with ortho-OH or ortho-NHR moieties to afford benzoxazoles and benzimidazoles, respectively.

Challenging the dogma: a randomized trial of standard vs. half-dose concomitant nonbismuth quadruple therapy for Helicobacter pylori infection

BACKGROUND

Current treatment of Helicobacter pylori consists of three or four drugs for 7-14 days with important associated cost and adverse events.

AIMS

This study compared efficacy and safety of standard dose vs. half-dose concomitant nonbismuth quadruple therapy (NBQT) for 7 days. The standard dose consisted of twice daily rabeprazole 20 mg, amoxicillin 1 g, metronidazole 500 mg, and clarithromycin 500 mg.

METHODS

This was a prospective randomized trial. (14)C-urea breath test was performed ≥4 weeks after treatment and ≥2 weeks off acid suppressive therapy. Compliance and adverse events were monitored during treatment.

RESULTS

A total of 200 consecutive treatment-naïve patients were enrolled. Baseline characteristics were similar between groups, with 15.5% of subjects reporting prior macrolide use. Eradication occurred in 78% (95% CI 68.6-85.7%) in both groups on intention-to-treat analysis. Per-protocol rates were 82.1 vs. 83.9% for standard-dose patients vs. half-dose patients, respectively (p = NS). Adverse events (only mild) were reported in 57 vs. 41% of standard-dose patients vs. half-dose patients (p = 0.024), with metallic taste and nausea notably less frequent in the latter (36 vs. 12% and 18 vs. 7%, respectively; p < 0.05 for both). Overall, eradication failed in 38.7% of prior macrolide users vs. 18.9% without such exposure (p = 0.019). On multivariate logistic regression, prior macrolide exposure was the only factor associated with failed eradication (OR 2.60, 95% CI 1.06-6.39; p = 0.038). Treatment was cheaper with the half-dose regimen.

INTERPRETATION

A 50% reduction in antibiotic dosage does not diminish efficacy of concomitant nonbismuth quadruple therapy but leads to significant reduction in cost and adverse events. Seven-day concomitant NBQT is suboptimal for H. pylori independent of prior macrolide exposure.

Rabeprazole- versus esomeprazole-based eradication regimens for H. pylori infection

BACKGROUND

Different kinds of proton pump inhibitor-based triple therapies could result in different Helicobacter pylori eradication rates.

AIM

The aims of this study were to compare the efficacy and safety of rabeprazole- and esomeprazole-based triple therapy in primary treatment of H. pylori infection in Taiwan.

PATIENTS AND METHODS

From June 2005 to March 2007, 420 H. pylori-infected patients were randomly assigned to receive a 7-day eradication therapy with either esomeprazole 40 mg daily (EAC group, n = 209) or rabeprazole 20 mg b.i.d. (RAC group, n = 211) in combination with amoxicillin 1 g b.i.d. and clarithromycin 500 mg b.i.d.. Follow-up endoscopy with biopsy was done 12-16 weeks after completion of eradication therapy. Those who refused endoscopic exams underwent (13)C-urea breath test to assess the treatment response.

RESULTS

Intention-to-treat analysis revealed that the eradication rate was 89.4% in the EAC group and 90.5% in RAC groups (p-value = .72). All of the subjects returned for assessment of compliance (100% in EAC group vs. 99.5% in RAC group, p-value = .32) and adverse events (3.83% in EAC group vs. 6.16% in RAC group, p-value = .27). Sixty (28.7%) and 37 (17.6%) patients in EAC and RAC group, respectively, refused endoscopy and underwent a (13)C-urea breath test to determine the treatment effect.

CONCLUSION

In conclusion, rabeprazole- and esomeprazole-based primary therapies for H. pylori infection are comparable in efficacy and safety.