Rabeprazole 10 mg twice daily is superior to 20 mg once daily for night-time gastric acid suppression

The role of vonoprazan in patients with erosive esophagitis

Acid suppression is the primary therapy for erosive esophagitis (EE). Although proton pump inhibitors (PPIs) are considered as the first-line medication for EE, 10-20% of patients with Los Angeles C and D grade EE do not gain complete mucosal healing and symptom control despite 8-week double-dose PPI treatment. Vonoprazan is a novel potassium-competitive acid blocker (P-CAB), which blocks the H+, K+-adenosine triphosphatase enzymes in a K+-competitive and reversible manner. Vonoprazan exhibits different pharmacological and pharmacokinetic profiles from conventional PPIs, and has a rapid, potent and sustained acid inhibitory effect. In this review, we summarized and discussed current evidence regarding the role of vonoprazan in terms of mucosal healing, maintaining remission and symptom relief for the management of EE, including the initial and maintenance treatment of EE, as well as for PPI-resistant EE patients. Safety concerns and cost-effectiveness analysis of vonoprazan were also mentioned in the article. As a potent and well-tolerated acid blocker, vonoprazan has the potential to become a novel option for the management of EE.

Efficacy and safety of twice-daily rabeprazole maintenance therapy for patients with reflux esophagitis refractory to standard once-daily proton pump inhibitor: the Japan-based EXTEND study

BACKGROUND

Rabeprazole at 10 or 20 mg twice daily (b.i.d.) has been reported to be highly effective in the treatment of proton pump inhibitor (PPI)-resistant reflux esophagitis (RE) that is refractory to the standard once-daily PPI regimen. We evaluated the efficacy and safety of rabeprazole maintenance therapy at 10 mg once daily (q.d.) or b.i.d. for longer than 8 weeks.

METHODS

Patients with RE refractory to standard PPI regimens for at least 8 weeks were enrolled. They were treated with rabeprazole at 10 or 20 mg b.i.d. for 8 weeks during the open-label treatment period. After endoscopic examination, those with confirmed healing entered the subsequent double-blind maintenance therapy. During this period, the subjects were randomized to receive rabeprazole 10 mg q.d. (control) or 10 mg b.i.d. The primary endpoint was the endoscopic no-recurrence rate at Week 52.

RESULTS

In total, 517 subjects entered the treatment, and 359 subjects continued on maintenance therapy. The full analysis set for central assessment included 343 subjects. The no-recurrence rate at Week 52 was significantly higher in the b.i.d. group (73.9%; p < 0.001, χ² test) than in the q.d. group (44.8%). In particular, the b.i.d. regimen was more effective in all subgroups with Los Angeles Classification Grade B to D at treatment entry.

CONCLUSIONS

In the maintenance treatment of PPI-resistant RE, rabeprazole at 10 mg b.i.d. exerted a stronger recurrence-preventing effect than 10 mg q.d. over 52 weeks. No particular safety issues were noted during long-term administration. ClinicalTrials.gov number: NCT02135107.

A Meta-Analysis and Systematic Review of the Efficacy of Twice Daily PPIs versus Once Daily for Treatment of Gastroesophageal Reflux Disease

Background

To investigate whether PPIs BID is superior to QD for treatment of GERD in a short time.

Methods

We searched PubMed, Cochrane Library, Scopus, EMBASE, Ovid, EBSCO, and Web of Science databases (from 1998 to May 2016) to select RCTs, which compared the efficacy of PPIs BID versus QD for GERD. The primary outcomes were symptom relief or esophageal mucosal healing at weeks 4 and 8. The M-H method with fixed-effect or random-effect model was used to calculate RR and 95% CIs.

Results

Seven RCTs were enrolled. The esophageal healing rates were higher in PPIs BID group (P = 0.01), and rabeprazole 20 mg BID can achieve better mucosal healing than 20 mg QD after 8 weeks (P < 0.05). However, no significant differences were observed in heartburn relief (P = 0.27), sustained symptom relief rates at week 4 (P = 0.05), 24 h pH monitoring after treatment (P = 0.11), endoscopic response at week 4 (P = 0.22), and adverse events (P = 0.18).

Conclusion

PPIs BID more effectively improve endoscopic healing rate at week 8 than PPIs QD. But there are no significant differences in symptom relief, 24 h pH monitoring, sustained symptom relief, and endoscopic response at week 4.

Therapeutic Response to Twice-daily Rabeprazole on Health-related Quality of Life and Symptoms in Patients with Refractory Reflux Esophagitis: A Multicenter Observational Study

Objective To investigate the effect of twice-daily rabeprazole doses on health-related quality of life in refractory patients. Methods and Patients Reflux esophagitis patients with an insufficient response to once-daily proton pump inhibitor therapy (Los Angeles Classification grade A-D) received rabeprazole 10 mg or 20 mg twice daily for 8 weeks. The health-related quality of life (SF-8™) and symptoms, using the Frequency Scale for the Symptoms of Gastroesophageal reflux disease, were evaluated before treatment and at weeks 4 and 8. Endoscopy was performed at baseline and at weeks 8 and 32 where possible. The rabeprazole dose was determined by the attending physician. Results There were 1,796 patients analyzed for the efficacy of the twice-daily treatment. Of these cases, 1,462 were treated with rabeprazole 10 mg twice daily, and 334 were treated with rabeprazole 20 mg twice daily. The factors that affected the selection of the twice-daily rabeprazole dose by physicians were evaluated, and as expected, "endoscopic findings when treatment was started" had a strong effect on the selection of the rabeprazole dose. With both regimens, health-related quality of life and subjective symptoms were significantly improved at weeks 4 and 8 compared to baseline (p<0.001). The recurrence rate of erosive esophagitis at week 32 was 9.7% in rabeprazole twice daily-treated patients and 28.4% in proton pump inhibitor (PPI) once daily-treated patients. Both regimens were well tolerated. Conclusion Twice-daily treatment with rabeprazole improved the subjective symptoms and health-related quality of life in patients with refractory reflux esophagitis more effectively than the standard once-daily dose.

A Multicenter, Randomized, Open-Label Trial: Efficacy of Once-Daily Versus Twice-Daily Double-Dose Rabeprazole on Refractory Gastroesophageal Reflux Disease-Related Symptoms and Quality of Life

Background

Approximately 20% to 40% of patients with gastroesophageal reflux disease (GERD) are refractory to standard-dose proton-pump inhibitor (PPI) treatment.

Objective

We compared the efficacy and quality-of-life effects of 20 mg once daily (QD) versus 10 mg twice daily (BID) rabeprazole (RPZ) in patients with refractory GERD-related symptoms and sleep disturbances.

Methods

This multicenter, prospective, randomized, open-label study included patients in whom PPI treatment >4 weeks was ineffective. According to the Global Overall Symptom (GOS) scale, PPI-refractory GERD was defined as ≥1 category with >3 points among 10 specific upper gastrointestinal symptoms. Seventy-eight patients were randomly assigned to 20 mg QD and 10 mg BID RPZ groups for 8 weeks. Efficacy was evaluated using self-reported questionnaires, including the GOS scale and Pittsburg Sleep Quality Index (PSQI), whereas quality of life was assessed using the Short-Form 8 Health Survey (SF-8), at 4 and 8 weeks. Patients showing improvement at 8 weeks received follow-up every 4 to 8 weeks.

Results

GOS scale scores were significantly improved at 8 weeks in both groups, with no significant intergroup differences. Although SF-8 scores showed an increasing trend over 8 weeks in both groups, the physical component summaries in the 10 mg BID group significantly improved. The mental component summaries clearly improved in the 10 mg BID group. Of the 74 cases (4 missing), 51 (68.9%) had PSQI scores ≥5.5. PSQI scores remained unchanged during follow-up in both groups. The recurrence rate was not significantly different (46.1% vs 47.1% in the 20 mg QD and 10 mg BID groups, respectively) during the follow-up period at median (interquartile range) 24.0 (30.5) months.

Conclusions

In patients with refractory GERD, there was no significant difference in GOS scale score, PSQI, or recurrence rate between the groups. With regard to subscores of the SF-8, the 10 mg BID group might be potentially effective.

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This multicenter prospective randomized comparative study compares the efficacy on symptoms, QOL and sleep disturbance between two ways of double dose PPI; once-daily 20mg RPZ or twice-daily 10mg RPZ.

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The patients with PPI refractory GERD were suffered from severe acid reflux symptoms, sleep disturbance and general distress. For these reasons, to establish the treatments to refractory GERD was important to improve their QOL. In patients with refractory GERD, there was no significant difference in GOS, PSQI, or recurrence rate between the groups.

Sleep disturbances and refractory gastroesophageal reflux disease symptoms in patients receiving once-daily proton pump inhibitors and efficacy of twice-daily rabeprazole treatment

BACKGROUND

Nighttime acid reflux that influences refractory symptoms is strongly associated with sleep disturbances. The aim of this study was to examine the associations between sleep disturbances and refractory gastroesophageal reflux disease (GERD) symptoms in patients receiving once daily proton pump inhibitors (PPI) and the efficacy of twice-daily rabeprazole treatment.

METHOD

In a multicenter survey, 433 GERD patients receiving once-daily PPI treatment completed a self-report questionnaire that included the Frequency Scale for the Symptoms of GERD (FSSG) and questions about sleep disturbances. Study cases were defined as patients with an FSSG score ≥8. Of the 222 study cases, 106 individuals received rabeprazole 10 mg twice daily for 4-8 weeks.

RESULTS

Of the 433 subjects, 222 patients revealed FSSG scores of ≥8. Use of a half dose of PPI was associated with such cases. PPI-refractory symptoms were found in 46% of patients with standard-dose PPI treatment. Nighttime symptoms (OR = 2.56), daytime sleepiness (OR = 1.64), and poorer sleep quality (OR = 1.67) were significantly associated with refractory GERD symptoms. Twice-daily rabeprazole treatment significantly improved FSSG scores and sleep disturbances.

CONCLUSION

About half of the GERD patients receiving once-daily standard-dose PPI treatment had refractory GERD symptoms. Sleep disturbances were significantly associated with refractory GERD symptoms. Twice-daily rabeprazole treatment was effective in such cases.

Efficacy of tailored Helicobacter pylori eradication therapy based on antibiotic susceptibility and CYP2C19 genotype

The cure rates of Helicobacter pylori (H. pylori) eradication therapy using a proton pump inhibitor (PPI) and antimicrobial agents such as amoxicillin, clarithromycin, and metronidazole are mainly influenced by bacterial susceptibility to antimicrobial agents and the magnitude of the inhibition of acid secretion. Annual cure rates have gradually decreased because of the increased prevalence of H. pylori strains resistant to antimicrobial agents, especially to clarithromycin. Alternative regimens have therefore been developed incorporating different antimicrobial agents. Further, standard PPI therapy (twice-daily dosing) often fails to induce a long-term increase in intragastric pH > 4.0. Increasing the eradication rate requires more frequent and higher doses of PPIs. Therapeutic efficacy related to acid secretion is influenced by genetic factors such as variants of the genes encoding drug-metabolizing enzymes (e.g., cytochrome P450 2C19, CYP2C19), drug transporters (e.g., multidrug resistance protein-1; ABCB1), and inflammatory cytokines (e.g., interleukin-1β). For example, quadruple daily administration of PPI therapy potently inhibits acid secretion within 24 h, irrespective of CYP2C19 genotype. Therefore, tailored H. pylori eradication regimens that address acid secretion and employ optimal antimicrobial agents based on results of antimicrobial agent-susceptibility testing may prove effective in attaining higher eradication rates.

Twice-daily dosing of esomeprazole effectively inhibits acid secretion in CYP2C19 rapid metabolisers compared with twice-daily omeprazole, rabeprazole or lansoprazole

BACKGROUND

Twice-daily dosing of proton pump inhibitors (PPIs) is used to treat Helicobacter pylori or acid-related diseases, such as gastro-oesophageal reflux disease (GERD) refractory to standard dose of a PPI. Genetic polymorphisms of CYP2C19 are involved to different extents in the metabolism of four kinds of PPIs (omeprazole, lansoprazole, rabeprazole and esomeprazole) available in Japan.

AIM

To compare acid-inhibitory effects of the four PPIs dosed twice daily in relation to CYP2C19 genotype.

METHODS

We performed 24-h pH monitoring studies on Day 7 of PPI treatment for 40 Japanese H. pylori-negative volunteers [15 CYP2C19 rapid metabolisers (RMs), 15 intermediate metabolisers (IMs) and 10 poor metabolisers (PMs)] using a randomised four-way crossover design: omeprazole 20 mg, esomeprazole 20 mg, lansoprazole 30 mg and rabeprazole 10 mg twice daily.

RESULTS

Although median pH values with esomeprazole, omeprazole, lansoprazole and rabeprazole were 5.7 (3.5-7.2), 5.5 (2.4-7.2), 5.5 (3.7-7.3) and 5.2 (2.5-7.3), respectively (no statistically significant differences), CYP2C19 genotype-dependent differences were smaller for esomeprazole and rabeprazole compared with values for omeprazole and lansoprazole. In CYP2C19 RMs, the median pH with esomeprazole [5.4 (3.5-6.8)] was significantly higher than those with omeprazole [5.0 (2.4-5.9), P = 0.018], lansoprazole [4.7 (3.7-5.5), P = 0.017] or rabeprazole [4.8 (2.5-6.4), P = 0.002]. In IMs and PMs, the median pH was >5.0 independent of the PPI.

CONCLUSIONS

In intermediate and rapid metabolisers of CYP2C19, PPIs dosed twice daily could attain sufficient acid suppression, while in CYP2C19 RMs, esomeprazole 20 mg twice daily caused the strongest inhibition of the four PPIs. Therefore, esomeprazole may be effective in Japanese population when dosed twice daily.

Individualized therapy for gastroesophageal reflux disease: potential impact of pharmacogenetic testing based on CYP2C19

The main therapeutic agent for gastroesophageal reflux disease (GERD) is a proton pump inhibitor (PPI). Plasma levels and the acid inhibitory effect of PPIs depend on the activity of cytochrome P450 (CYP) 2C19, which is polymorphic. Genotypes of CYP2C19 are classified into three groups: rapid metabolizers (RMs: *1/*1), intermediate metabolizers (IMs: *1/*X), and poor metabolizers (PMs: *X/*X), where *1 and X represent the wild type and the mutant allele, respectively. RMs include ultra-rapid metabolizers, who possess the CYP2C19*17 allele. The pharmacokinetics and pharmacodynamics of PPIs differ among different CYP2C19 genotype groups. Plasma PPI levels and intragastric pH values during PPI treatment are lowest in the RM group, intermediate in the IM group, and highest in the PM group. These CYP2C19-genotype-dependent differences in the pharmacokinetics and pharmacodynamics of PPIs influence the healing and recurrence of GERD during PPI treatment, suggesting the need for CYP2C19 genotype-based tailored therapy for GERD. CYP2C19 pharmacogenetics should be taken into consideration for the personalization of PPI-based therapy. However, the clinical usefulness of CYP2C19 genotype testing in GERD therapy should be verified in clinical studies.

Individualized therapy for gastroesophageal reflux disease: potential impact of pharmacogenetic testing based on CYP2C19

The main therapeutic agent for gastroesophageal reflux disease (GERD) is a proton pump inhibitor (PPI). Plasma levels and the acid inhibitory effect of PPIs depend on the activity of cytochrome P450 (CYP) 2C19, which is polymorphic. Genotypes of CYP2C19 are classified into three groups: rapid metabolizers (RMs: *1/*1), intermediate metabolizers (IMs: *1/*X), and poor metabolizers (PMs: *X/*X), where *1 and X represent the wild type and the mutant allele, respectively. RMs include ultra-rapid metabolizers, who possess the CYP2C19*17 allele. The pharmacokinetics and pharmacodynamics of PPIs differ among different CYP2C19 genotype groups. Plasma PPI levels and intragastric pH values during PPI treatment are lowest in the RM group, intermediate in the IM group, and highest in the PM group. These CYP2C19-genotype-dependent differences in the pharmacokinetics and pharmacodynamics of PPIs influence the healing and recurrence of GERD during PPI treatment, suggesting the need for CYP2C19 genotype-based tailored therapy for GERD. CYP2C19 pharmacogenetics should be taken into consideration for the personalization of PPI-based therapy. However, the clinical usefulness of CYP2C19 genotype testing in GERD therapy should be verified in clinical studies.

Gastroesophageal reflux disease and sleep disturbances

Nighttime reflux during sleep plays a crucial role in several conditions associated with gastroesophageal reflux disease (GERD). Reflux patterns during arousal and sleep are different because of delayed gastric emptying, reduced esophageal peristalsis, decreases in swallowing and salivary secretion, and prolonged esophageal clearance during sleep. Clinical evidence strongly suggests that GERD is associated with sleep disturbances such as shorter sleep duration, difficulty falling asleep, arousals during sleep, poor sleep quality, and awakening early in the morning. New mechanisms on how GERD affects sleep have been recently identified by using actigraphy, and sleep deprivation was found to induce esophageal hyperalgesia to acid perfusion. Thus, the relationship between GERD and sleep disturbances is bidirectional. Among lifestyle modifications, avoidance of a late night meal plays a role in prevention of nighttime reflux. Treatment with a proton pump inhibitor (PPI) improves both nighttime symptoms and subjective sleep parameters, but its effects on objective sleep parameters remain unclear. Better control of nighttime acid secretion by administering a PPI at different times or by providing a double-dose PPI, adding H(2) receptor antagonists, or other new agents is proposed. The effects of such treatments on sleep disturbances remain to be elucidated. GERD patients with sleep disturbances report more severe symptoms and poorer quality of life as compared to those without sleep disturbances. Consequently, GERD should also be classified as GERD with sleep disturbance and GERD without sleep disturbance.

Predicting the efficacy of proton pump inhibitors in patients with non-erosive reflux disease before therapy using dual-channel 24-h esophageal pH monitoring

BACKGROUND AND AIM

We aimed to determine whether reflux- and symptom-related parameters can predict the efficacy of proton pump inhibitors (PPI) in non-erosive reflux disease (NERD).

METHODS

Twenty-seven NERD patients who had experienced heartburn more than once a week within the previous month were enrolled. Intraesophageal pH before therapy was measured simultaneously at 5 and 15 cm above the esophagogastric junction (EGJ) for 24 h. The PPI rabeprazole was administered at a dose of 10 mg once daily for 4 weeks. In the event that heartburn was not relieved, the dose was increased to 10 mg twice daily for an additional 2 weeks, and again to 20 mg twice daily for another 2 weeks.

RESULTS

Univariate analysis demonstrated no significant associations between any reflux- or symptom-related parameters at either site and complete heartburn relief after 4 weeks, or cumulative complete heartburn relief after 8 weeks. However, post-hoc analysis demonstrated more satisfactory heartburn relief after 4 weeks in patients with a high symptom index compared with those with a low symptom index, at 5 cm above the EGJ (P = 0.009). Cumulative satisfactory heartburn relief after 8 weeks was also greater in patients with a high total number of acid reflux episodes compared with those with a low total number of episodes, at 15 cm above the EGJ (P = 0.037).

CONCLUSIONS

Pre-therapeutic pH monitoring in the lower and mid-esophagus is useful for predicting the efficacy of PPI in NERD patients.

A comparison of the acid-inhibitory effects of esomeprazole and rabeprazole in relation to pharmacokinetics and CYP2C19 polymorphism

BACKGROUND

Esomeprazole and rabeprazole are metabolised in the liver by means of the CYP2C19 enzyme, which has several functional genetic polymorphisms. Among Caucasians, 70% of the population has a fast metaboliser phenotype, 25-30% an intermediate and 2-5% a slow metaboliser phenotype. It is unknown whether different PPIs are affected to the same extent by these phenotypic differences.

AIM

To compare the acid-inhibitory effects of esomeprazole 40 mg and rabeprazole 20 mg in relation to CYP2C19 genotype and pharmacokinetics.

METHODS

Eighteen healthy Helicobacter pylori-negative Caucasian subjects with CYP2C19*2-*6 and *17 genotype were included in a randomised investigator-blinded crossover study with esomeprazole 40 mg and rabeprazole 20 mg. Intragastric 24-h pH-monitoring was performed on days 0, 1 and 5 of oral dosing.

RESULTS

Onset of acid inhibition during the first 4 h after administration did not differ significantly between PPIs. During the upright period, the proportion of time with pH >4 was significantly higher with esomeprazole compared to rabeprazole (52.2 vs. 40.3%, P = 0.003). At day 1 and 5, acid inhibition was significantly greater with esomeprazole than with rabeprazole (median intragastric pH: day 1: 3.7 vs. 3.0, P = 0.008; day 5: 4.7 vs. 3.8, P < 0.001; percentage of time pH >4: day 1: 45 vs. 39%, P = 0.054; day 5: 65 vs. 48%, P < 0.001). Differences in acid inhibition between wt/wt and wt/*2 genotype were significant for both PPIs.

CONCLUSIONS

Once-daily dosing with esomeprazole 40 mg provides a more effective and faster acid-inhibitory effect than rabeprazole 20 mg. The acid-inhibitory effect of esomeprazole and rabeprazole are both influenced by CYP2C19 polymorphism.

Efficacy of twice-daily rabeprazole for reflux esophagitis patients refractory to standard once-daily administration of PPI: the Japan-based TWICE study

OBJECTIVES

Approximately 10% of patients with reflux esophagitis (RE) are not cured with the standard 8-week q.d. regimen with a proton pump inhibitor (PPI). Thus, b.i.d. dosing is often used in refractory RE (rRE) patients, although there has been no report of endoscopically confirmed healing with b.i.d. dosing of PPIs. This study aimed to assess the efficacy and safety of 8-week therapy with rabeprazole (RPZ) sodium at 20 mg b.i.d. or 10 mg b.i.d. as compared with RPZ at 20 mg q.d. in patients with RE refractory to the standard PPI regimen in Japan.

METHODS

Endoscopically confirmed rRE patients (Los Angeles grade A-D) who had received a standard PPI regimen for at least 8 weeks were randomized in a double-blind manner into groups receiving RPZ at 20 and 10 mg b.i.d. or 20 mg q.d. (control) daily for up to 8 weeks. The primary efficacy endpoint was the rate of endoscopically confirmed healing after week 8.

RESULTS

A total of 337 rRE patients treated at 71 sites were randomized. The rate of endoscopically confirmed healing after 8 weeks was significantly higher in those who received RPZ at 20 mg b.i.d. (77.0%, P = 0.003) and 10 mg b.i.d. (78.4%, P = 0.001) as compared with 20 mg q.d. (58.8%), and the rates of resolution of heartburn after week 8 were 80.0%, 74.0%, and 56.4%, respectively. All treatment regimens were well tolerated.

CONCLUSIONS

Regimens of RPZ at 20 and 10 mg b.i.d. for 8 weeks were more effective than 20 mg q.d. with regard to endoscopically confirmed healing and symptom resolution of RE refractory to a standard PPI regimen.

Investigation of pretreatment prediction of proton pump inhibitor (PPI)-resistant patients with gastroesophageal reflux disease and the dose escalation challenge of PPIs-TORNADO study: a multicenter prospective study by the Acid-Related Symptom Research Group in Japan

BACKGROUNDS

Some non-erosive reflux disease (NERD) and reflux esophagitis (RE) patients are unresponsive to a proton pump inhibitor (PPI) at standard dose. We investigated the predictive marker of the efficacy of PPI for GERD patients including NERD and RE treated with standard and increased doses of a PPI.

METHODS

Patients with symptomatic gastroesophageal reflux disease (GERD) (NERD and RE) were treated with rabeprazole (RPZ) 10 mg once daily for 4 weeks. The RPZ dosage was increased to 10 mg twice daily for an additional 2 weeks and again to 20 mg twice daily for another 2 weeks if heartburn was not relieved. Baseline characteristics and efficacy of RPZ were assessed on the basis of a heartburn diary and frequency scale for symptoms of GERD (FSSG).

RESULTS

Complete heartburn relief rates after 4 weeks were 42.5% (31/73) and 67.9% (19/28) in NERD and RE groups, respectively, which rose to 68.9 and 91.7% after dose escalation. Multivariate analysis revealed that parameters associated with resistance to RPZ 10 mg once daily were female, non-smoking, frequent heartburn, low score for question 4 (Q4) of the FSSG (subconsciously rubbing the chest), and high scores for Q3 (heavy stomach after meal) and Q7 (unusual sensation in the throat). Frequent heartburn and a high score for Q7 were associated with resistance to RPZ 20 mg twice daily. FSSG scores of patients resistant to RPZ were significantly higher in comparison with responders before and during treatment.

CONCLUSIONS

FSSG could predict response to a PPI for symptomatic GERD. Increase of RPZ dose is useful for treatment of GERD refractory to the standard dose of RPZ.

Effect of CYP2C19 genotypes on the pharmacokinetic/pharmacodynamic relationship of rabeprazole after a single oral dose in healthy Chinese volunteers

AIMS

To explore the pharmacokinetic/pharmacodynamic relationship of rabeprazole and the role of CYP2C19 genotypes after a single oral dose in healthy Chinese volunteers by a population approach.

METHODS

Plasma concentration time profile data and intragastric pH values of 19 genotyped healthy male adults after a single oral dose of rabeprazole in an open label randomized fashion were used for this population analysis. Simulation technology was performed to examine the rabeprazole response in subjects with different CYP2C19 genotypes to further investigate the effect of acid inhibition.

RESULTS

The pharmacokinetics of rabeprazole was characterized by a two-compartment model with first order absorption and with an absorption lag-time. The results show that clearance of rabeprazole was affected by CYP2C19 genotypes (average clearances of homEM, hetEM, and PM were 13.9, 11.5, and 8.74 L·h(-1) respectively). An effect compartment with a sigmoidal Emax model was considered more rational for analyzing the relationship between rabeprazole concentrations and intragastric pH values. Simulated results suggest that rabeprazole 20 mg once daily for PMs is sufficient, but might be administered more frequently for other genotypes in treating gastro-esophageal reflux disease.

CONCLUSION

The CYP2C19 genotype played a considerable role in the pharmacokinetic characteristics of rabeprazole, and this might need to be taken into account for clinical use.

Rabeprazole: a pharmacologic and clinical review for acid-related disorders

Rabeprazole is a proton pump inhibitor that can be used in the treatment of acid-peptic-related disorders (gastroesophageal reflux disease [GERD], duodenal ulcer, gastric ulcer, gastric acid hypersecretory syndromes) and Helicobacter pylori. Pharmacodynamic data has demonstrated that rabeprazole, with a high pKa of approximately 5.0, can be activated at a higher pH than other proton pump inhibitors. This possibly results in faster onset of action. Owing to its non-enzymatic pathway of metabolism, rabeprazole is also less influenced by genetic polymorphisms of the CYP2C19, which others proton pump inhibitors are dependent on. In a 2-week, placebo-controlled trial, rabeprazole was both rapid and effective in relieving heartburn on day 1 of therapy and improved other GERD-related symptoms including regurgitation, belching, bloating, early satiety and nausea. For oesophageal reflux disease without erosions both 10 and 20 mg of rabeprazole are equivalent and better than placebo at 2 and 4 weeks. An on-demand approach to non-erosive reflux disease with 10 mg of rabeprazole has also been documented as superior to placebo. Some success in the treatment of extra-oesophageal manifestations of GERD, such as asthma and chronic laryngitis, has also been achieved with rabeprazole. Overall, rabeprazole with very few side effects is a safe and efficacious medication for acid suppression therapy.

Low-dose aspirin affects the small bowel mucosa: results of a pilot study with a multidimensional assessment

BACKGROUND & AIMS

Whether low-dose aspirin (acetylsalicylic acid [ASA]) produces intestinal damage is controversial. Our aim was to determine whether the small bowel is damaged by low-dose ASA on a short-term basis.

METHODS

Twenty healthy volunteers (age range, 19-64 years) underwent video capsule endoscopy (VCE), fecal calprotectin, and permeability tests (sucrose and lactulose/mannitol [lac/man] ratio) before and after ingestion of 100 mg of enteric-coated ASA daily for 14 days. Video capsule images were assessed by 2 independent expert endoscopists, fully blinded to the treatment group, by using an endoscopic scale.

RESULTS

Post-ASA VCE detected 10 cases (50%) with mucosal damage not apparent in baseline studies (6 cases had petechiae, 3 had erosions, and 1 had bleeding stigmata in 2 ulcers). The median baseline lac/man ratio (0.021; range, 0.011-0.045) increased after ASA use (0.036; range, 0.007-0.258; P = .08), and the post-ASA lac/man ratio was above the upper end of normal (>0.025) in 10 of 20 volunteers (vs baseline, P < .02). The median baseline fecal calprotectin concentration (6.05 microg/g; range, 1.9-79.2) also increased significantly after ASA use (23.9 microg/g; range, 3.1-75.3; P < .0005), with 3 patients having values above the cutoff (>50 microg/g). Five of 10 subjects with abnormal findings at VCE also had lac/man ratios above the cutoff. Median baseline sucrose urinary excretion (70.0 mg; range, 11.8-151.3) increased significantly after ASA administration (107.0 mg; range, 22.9-411.3; P < .05).

CONCLUSIONS

The short-term administration of low-dose ASA is associated with mucosal abnormalities of the small bowel mucosa, which might have implications in clinical practice.

A systematic review of the definitions, prevalence, and response to treatment of nocturnal gastroesophageal reflux disease

BACKGROUND & AIMS

More than half of patients with chronic gastroesophageal reflux (GERD) report nocturnal symptoms. We performed systematic literature review to define nocturnal heartburn and to determine potential causality between nocturnal reflux and extraesophageal manifestations.

METHODS

We performed a search of literature published from 1974-2007. Each study was examined by 2 reviewers and rated on the basis of study type and outcome.

RESULTS

Screening of 445 trials identified 59 (13%) studies relevant for analysis. Twenty-two (5%) of the trials described potential changes in sleep parameters resulting from treatment of heartburn. In most studies, nocturnal reflux was defined as heartburn symptoms that impacted sleep quality and duration. On the basis of 5 large population studies, the mean +/- standard deviation prevalence of nocturnal heartburn was 54% +/- 22%. Consequences of nocturnal reflux included poor sleep quality, daytime fatigue, difficulty initiating sleep or arousals from sleep, and impaired work productivity. The strength of the association between the occurrence of nocturnal reflux and late evening meals was flawed as a result of the confounding effect of the evening meal content. There was no evidence supporting causality between nocturnal heartburn and asthma or obstructive sleep apnea. Subjective, but not objective, measures of sleep improved with antireflux therapy. Head of bed elevation, proton pump inhibitor therapy, H(2)-receptor antagonists, and Nissen fundoplication alleviated nocturnal heartburn and associated sleep disturbances.

CONCLUSIONS

Nocturnal GERD is common and is associated with adverse sleep parameters. It can be effectively managed with medical and surgical therapy.

Use of acid-suppressing drugs and the risk of bacterial gastroenteritis

BACKGROUND & AIMS

Gastric acid is a defense mechanism against gastrointestinal infections caused by ingested bacteria. Studies have suggested that the use of acid-suppressing drugs may increase the risk of gastroenteritis (GE).

METHODS

Patients aged 20-74 years with an episode of acute bacterial GE (n = 6414) were identified. A control group from the same study population without a diagnosis of GE (n = 50,000) was frequency-matched by age, sex, and calendar year to the case group. Unconditional logistic regression was used to calculate the adjusted relative risk (RR) of GE in patients using proton pump inhibitors (PPIs) or histamine-2 receptor antagonists (H2RAs).

RESULTS

Current use of PPIs was associated with an increased risk of bacterial GE compared with nonuse, regardless of the treatment duration (RR, 2.9; 95% confidence interval [CI], 2.5-3.5), whereas no association was observed with H2RA use (RR, 1.1; 95% CI, 0.9-1.4). Doubling the PPI dose further increased the risk of developing bacterial GE (RR, 5.0; 95% CI, 2.7-9.3). The effect of PPI use did not vary significantly with regard to treatment indication. The increased risk associated with PPI use was similar for both omeprazole (RR, 3.0; 95% CI, 2.5-3.7) and lansoprazole (RR, 2.1; 95% CI, 1.4-3.0), whereas neither cimetidine nor ranitidine showed any increased risk. Campylobacter (n = 4124) and Salmonella (n = 1885) were the 2 species most frequently responsible for GE episodes in the case group. When analyzed separately, both species reproduced the increased risk associated with PPI use and not H2RA use. Clostridium GE cases were rare (n = 31).

CONCLUSIONS

This study suggests that gastric acid suppression induced by PPIs but not H2RAs is associated with an increased risk of Campylobacter and Salmonella GE.

Treatment strategy to eradicate Helicobacter pylori infection: impact of pharmacogenomics-based acid inhibition regimen and alternative antibiotics

The eradication rates of Helicobacter pylori by the triple therapy consisting of a proton pump inhibitor (PPI) and two antimicrobial agents are mainly influenced by bacterial susceptibility to antimicrobial agents and magnitude of acid inhibition during the treatment with a PPI. Acid inhibition during the treatment is affected by the dosing schemes of acid inhibitory drugs (i.e., PPI), genotypes of drug-metabolizing enzymes (i.e., CYP450 2C19), drug transporters (i.e., multi-drug resistant transporter-1) and inflammatory cytokines (i.e., IL-1 beta). Modification of dosing schedules of a PPI, such as frequent PPI dosing and concomitant dosing with a histamine 2-receptor antagonist, could overcome these genetics-related differences in therapeutic effectiveness. For attaining higher eradication rates, the tailored regimen based on the relevant pharmacogenomics is preferable.

Acid-suppressive effects of rabeprazole: comparing 10mg and 20mg twice daily in Japanese Helicobacter pylori-negative and -positive CYP2C19 extensive metabolisers

BACKGROUND

Rabeprazole 10mg b.i.d. is often administered as therapy for eradication of Helicobacter pylori (H. pylori) and is also proposed as therapy for refractory gastro-oesophageal reflux disease. However, there has not been a comprehensive assessment of its acid-suppressive effects.

AIMS

To compare the acid-suppressive effects of rabeprazole 10mg b.i.d. with 20mg b.i.d. considering H. pylori status.

SUBJECTS

Thirteen H. pylori-negative and eleven H. pylori-positive Japanese CYP2C19 extensive metabolisers (<35 years).

METHODS

Intragastric pH was measured for 24h three times in a randomised manner; on day 7 of the repeated administration of rabeprazole 10mg b.i.d. or 20mg b.i.d., or a placebo.

RESULTS

In median intragastric pH value and percent time of pH>3.0, >4.0, >5.0, >6.0, and >7.0 for 24h, no significant differences were observed between the two doses in either H. pylori-negative or H. pylori-positive subjects. At either dose, these parameters were significantly higher in H. pylori-positive subjects than in H. pylori-negative subjects. Nocturnal acid breakthrough occurred in seven and two of the thirteen H. pylori-negative subjects and one and two of the eleven H. pylori-positive subjects at each dose, respectively.

CONCLUSIONS

The effects of rabeprazole 10mg b.i.d. were equal to those of 20mg b.i.d. in H. pylori-positive subjects; whereas in H. pylori-negative subjects, 20mg b.i.d. was superior for prevention of nocturnal acid breakthrough.

Role of nitric oxide in the protective effect of rabeprazole on gastric mucosal lesions in rats

AIM: To explore the role of nitric oxide (NO) in the protective effect of rabeprazole on the gastric mucosal lesions in rats.

METHODS: Before gastric mucosal lesion was made in rats by pure alcohol, rabeprazole (20 mg/kg) was administered into the gastric chamber and Nw-nitro-l-arginine methyl ester (l-NAME, 4 mg/kg), l-arginine (250 mg/kg) and d-arginine (250 mg/kg) were injected into the vein. Gastric mucosal blood flow (GMBF) was assessed with laser Doppler flowmetry (LDF); gastric mucosal and serum NO^-₂/NO^-₃ were measured by cadmium granulation reduction and colorimetric method; and the changes of ulcer index and the severity of tissue necrosis as well as neutrophil infiltration were observed.

RESULTS: The Ulcer index of the rabeprazole group was markedly lower than that in the controls (5.5 ± 0.5 vs 25.2 ± 2.3, P < 0.01), and the degrees of tissue necrosis and neutrophil infiltration were significantly milder (necrosis ++ - +++/≤+: 1/9 vs 8/2, P < 0.01; infiltration ++ - +++/≤+: 3/7 vs 9/1, P < 0.01). The protective effect of rabeprazole was significantly decreased by prior administration of l-NAME. The inhibitory effect of l-NAME was antagonized by prior administration of l-arginine, but not d-arginine. Rabeprazole administered into the gastric chamber obviously increased GMBF, gastric mucosal and serum NO^-₂/NO^-₃, which was prevented by pretreatment with l-NAME, but the antisecretory effect of rabeprazole was not affected by l-NAME.

CONCLUSION: Rabeprazole can exert important protection against gastric mucosal lesions in rats mediated by nitric oxide, and the action of rabeprazole against gastric acid secretion contributes little to the protective effect.

Different effects of fluvoxamine on rabeprazole pharmacokinetics in relation to CYP2C19 genotype status

AIMS

Rabeprazole is known to be a substrate of CYP2C19. Our objective was to evaluate the possible effect of an inhibitor of CYP2C19, fluvoxamine, and compare the inhibitory effect of fluvoxamine on the metabolism of rabeprazole between CYP2C19 genotypes.

METHODS

A two-way randomized double-blind, placebo-controlled crossover study was performed. Twenty-one volunteers, of whom seven were homozygous extensive metabolizers (EMs), eight were heterozygous EMs and six were poor metabolizers (PMs) for CYP2C19, received two 6-day courses of either fluvoxamine 50 mg or placebo daily in a randomized fashion with a single oral dose of rabeprazole 20 mg on day 6 in all cases. Plasma concentrations of rabeprazole and its metabolite rabeprazole thioether were monitored up to 24 h after dosing.

RESULTS

During placebo administration, the mean AUCs(0,infinity) of rabeprazole in homozygous EMs, heterozygous EMs and PMs were 882 (95% CI, 602, 1162) ng ml-1h , 1214 (975, 1453) ng ml-1 h and 2762 (2482, 3042) ng ml-1 h (P<0.001), respectively. Fluvoxamine treatment increased AUC(0,infinity) of rabeprazole and rabeprazole thioether by 2.8-fold (P<0.001) and 5.1-fold (P<0.01) in homozygous EMs, and by 1.7-fold (P<0.01) and 2.6-fold (P<0.01) in heterozygous EMs, and significantly prolonged the elimination half-life of rabeprazole and rabeprazole thioether in homozygous EMs and in heterozygous EMs, whereas no difference in any pharmacokinetic parameters was found in PMs. There was a significant difference in fluvoxamine-mediated percentage increase in AUC(0,infinity) of rabeprazole and rabeprazole thioether between CYP2C19 genotypes.

CONCLUSIONS

The present study indicates that there are significant drug interactions between rabeprazole and fluvoxamine in EMs of CYP2C19. It is predominantly involved in rabeprazole and rabeprazole thioether metabolism in EMs. Therefore, CYP2C19 is the key determinant of rabeprazole disposition in EMs.

Therapeutic effects of 10 mg/day rabeprazole administration on reflux esophagitis was not influenced by the CYP2C19 polymorphism

BACKGROUND

The acid suppressive effects of omeprazole (OPZ) and lansoprazole (LPZ) are influenced by the CYP2C19 polymorphism. On the other hand, some investigators have reported that acid suppressive effect of rabeprazole (RPZ) was not significantly affected by CYP2C19. The present study was designed to investigate whether the CYP2C19 genotype is related to the healing of reflux esophagitis (RE) in treatment with RPZ 10 mg.

METHODS

One hundred and three Japanese patients with RE were treated with daily oral administration of 10 mg RPZ. At 4 and 8 weeks after the start of treatment, healing of RE was evaluated endoscopically. The CYP2C19 genotype was investigated before the treatment.

RESULTS

At 4 weeks after the start of treatment, the healing rates for homo-extensive metabolizer, hetero-extensive metabolizer, and poor metabolizer patients were 83.3% (15/18), 77.3% (17/22), and 88.9% (8/9) [corrected] respectively, and at 8 weeks after the start of treatment, the healing rates were 86.1% (31/36), 92.0% (46/50), and 82.4% (14/17), respectively. There were no significant differences in the healing rate of RE among the three genotypes at either 4 or 8 weeks after the start of treatment.

CONCLUSIONS

The therapeutic effects of 10 mg/day RPZ administration on RE may be uninfluenced by the CYP2C19 polymorphism.

Effects of clarithromycin and verapamil on rabeprazole pharmacokinetics between CYP2C19 genotypes

OBJECTIVE

Rabeprazole as a proton pump inhibitor (PPI) is mainly reduced to rabeprazole thioether via a nonenzymatic pathway, with minor CYP2C19 and CYP3A4 involvement. The aim of this study was to compare possible effects of clarithromycin and verapamil as inhibitors of CYP3A4 on the pharmacokinetics of rabeprazole among CYP2C19 genotypes.

METHODS

A three-way randomized, double-blind, placebo-controlled crossover study was performed. Nineteen volunteers, of whom six were homozygous extensive metabolizers (EMs), eight were heterozygous EMs, and five were poor metabolizers (PMs) for CYP2C19, received three 6-day courses of either daily 800 mg clarithromycin, 240 mg verapamil, or placebo in a randomized fashion, with a single oral dose of 20 mg rabeprazole on day 6 in all cases. Plasma concentrations of rabeprazole and rabeprazole thioether were monitored up to 24 h after the dosing.

RESULTS

In the control phase, the AUC(0-infinity) values for rabeprazole and rabeprazole thioether were 1,005+/-366 and 412+/-149 ng.h/ml in homozygous EMs, 1,108+/-340 and 491+/-245 ng.h/ml in heterozygous EMs, and 2,697+/-364 and 2,116+/-373 ng.h/ml in PMs, respectively. There were significant differences (p<0.001) in the AUC(0-infinity) of rabeprazole and rabeprazole thioether among three different CYP2C19 genotypes. In the clarithromycin and verapamil phases, no significant differences were found in the pharmacokinetic parameters of rabeprazole compared with those in the control phase irrespective of CYP2C19 genotypes, whereas the AUC(0-infinity) of rabeprazole thioether was significantly increased 2.8-fold and 2.3-fold in homozygous EMs (p<0.01), 2.0-fold and 2.0-fold in heterozygous EMs (p<0.05), and 1.6-fold and 1.9-fold in PMs (p<0.05), respectively. In each genotype group for CYP2C19, there were no statistical differences in the percent increase in those pharmacokinetic parameters between the clarithromycin and verapamil pretreatment phases.

CONCLUSION

The pharmacokinetic parameters of rabeprazole were not altered by clarithromycin or verapamil irrespective of the CYP2C19 genotypes. However, this result shows that both clarithromycin and verapamil significantly influence the disposition of rabeprazole by inhibiting the oxidation of the thioether, since the AUC(0-infinity) of rabeprazole thioether that has no effect on acid secretion increased. Therefore, the pharmacokinetic interactions between rabeprazole and CYP3A4 or P-glycoprotein inhibitors have limited clinical significance.

Comparison of the effects of fasting morning, fasting evening and fed bedtime administration of tenatoprazole on intragastric pH in healthy volunteers: a randomized three-way crossover study

BACKGROUND

The effectiveness of proton pump inhibitors is influenced by meals and administration time.

AIM

To compare the effects on intragastric acidity of times of dosing of tenatoprazole, a novel imidazopyridine-based proton pump inhibitor with a prolonged plasma half-life.

METHODS

This randomized three-period crossover study included 12 Helicobacter pylori-negative healthy subjects, who received tenatoprazole 40 mg either fasting at 7.00 AM, fasting at 7.00 PM or fed at 9.30 PM for 7 days, with a 2-week washout between periods. Twenty-four hour intragastric pH was monitored on day 7 of each period.

RESULTS

On day 7, median 24-h pH was 4.7, 5.1 and 4.7 after breakfast, dinner and bedtime dosing, respectively (P = 0.11), whereas night-time pH was 4.2, 5.0 and 4.4 (P = 0.13). The mean 24-h percentage of time over pH 4 was 62, 72 and 64 after breakfast, dinner and bedtime dosing, respectively (N.S.), and 54, 68 and 56 during night-time (P = 0.06). Nocturnal acid breakthrough incidence decreased from 100% at baseline to 83%, 55% and 75% after 7.00 AM, 7.00 PM and 9.30 PM dosing, respectively (P = 0.18), and its mean duration dropped from 6.2 to 2.8, 1.0 and 2.2 h, respectively (P < 0.05).

CONCLUSION

Seven-day administration of tenatoprazole provides a prolonged duration of acid suppression, especially during the night-time, with little effect of food or time of dosing.

Acid-suppressive efficacy of a reduced dosage of rabeprazole: comparison of 10 mg twice daily rabeprazole with 20 mg twice daily rabeprazole, 30 mg twice daily lansoprazole, and 20 mg twice daily omeprazole by 24-hr intragastric pH-metry

Rabeprazole achieves more potent acid suppression than other proton pump inhibitors. Therefore it is administered at reduced as well as high dosages in eradication therapy for Helicobacter pylori; however, there is incomplete assessment of the efficacy of a reduced dosage of rabeprazole as might be employed in therapy. In this study, we evaluated acid-suppressive efficacy of a reduced dosage of rabeprazole on day 7 by 24-hr pH-metry in 10 healthy male cytochrome P-450 2C19 extensive metabolizers without Helicobacterpylori infection and compared the results with those of high dosages of rabeprazole, lansoprazole, and omeprazole. Median intragastric pH value, pH >3 holding time ratio (pH>3HT), pH>4HT, pH>5HT, pH>6HT, and pH>7HT for 24 hr with rabeprazole, 10 mg twice daily, were not significantly different from those of rabeprazole, 20 mg twice daily, lansoprazole, 30 mg twice daily, and omeprazole, 20 mg twice daily. In conclusion, for acid-suppressive efficacy, a reduced dosage of rabeprazole is comparable to high dosages of rabeprazole, lansoprazole, and omeprazole.