A placebo-controlled trial to assess the effects of 8 days of dosing with rabeprazole versus omeprazole on 24-h intragastric acidity and plasma gastrin concentrations in young healthy male subjects

Gastro‑oesophageal reflux disease in liver cirrhosis: Possible pathogenesis and clinical intervention (Review)

Oesophageal variceal bleeding is a common complication of decompensated liver cirrhosis (LC). Some studies have reported that reflux oesophagitis (RE) is a risk factor for upper gastrointestinal bleeding, and greatly impacts the quality of life. However, the frequency and mechanism of gastro-oesophageal reflux disease (GERD) in LC remain unclear. The present review explored the possible pathogenesis, and analysed the advantages and disadvantages of the interventional measures and the need for implementation of these measures. By combining the comprehensive terms associated with LC, GERD and RE, EMBASE, Medline/PubMed and the Cochrane Library were systematically searched. The underlying pathological mechanism of GERD in LC was summarized: Transient relaxation of the lower oesophageal sphincter, delayed gastric emptying, increased intra-abdominal pressure, increased intragastric pressure and excessive nitric oxide production destroyed the 'anti-reflux barrier', causing gastric content reflux. Proton pump inhibitors (PPIs) have been widely used empirically to lower the risk of oesophageal venous rupture and bleeding. However, long-term use of acid inhibitors in patients with LC may induce complications, such as spontaneous bacterial peritonitis. The metabolic half-life of PPIs is prolonged in patients with severe liver function impairment. Therefore, the indications for using acid inhibitors lack clarity. However, after endoscopic oesophageal variceal eradication, additional benefits may be gained from the long-term use of PPIs in small doses.

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.

Gastrin and the Moderate Hypergastrinemias

The antral hormone gastrin potently regulates gastric acid secretion and fundic mucosal growth. Consequently, appropriate gastrin secretion and plasma concentrations are important for the early phases of digestion. This review describes as the first premise the normal biogenesis of gastrin in the antral mucosa, but also mentions the extraantral expression. Subsequently, the molecular nature and concentration levels of gastrin in serum or plasma are overviewed. Third, assays for accurate measurements of plasma or serum concentrations are commented. Finally, the problem of moderate hypergastrinemia due to Helicobacter pylori infections and/or treatment with proton-pump inhibitors (PPI) is discussed. The review concludes that accurate measurement of the true concentrations of bioactive gastrins in plasma is important. Moreover, it suggests that moderate hypergastrinemias are also essential health issues that require serious attention.

Rabeprazole: A comprehensive profile

Rabeprazole belongs to the class of anti-secretory drugs, with benzimidazoles substitution. These drugs induce gastric acid secretion through precise inhibition of the enzyme H⁺/K⁺-ATPase (acid or proton pump). This effect helps to treat and prevent conditions in which gastric acid directly aggravates symptoms such as duodenal and gastric ulcers. This chapter includes a comprehensive review of rabeprazole in terms of nomenclature, its physical-chemical properties, methods of preparation and ADME profiles. In addition, the chapter also includes a review of several methods for analysis of rebeprazole in its dosage forms and biological fluids.

Randomised clinical trial: vonoprazan versus lansoprazole for the initial relief of heartburn in patients with erosive oesophagitis

BACKGROUND

Proton pump inhibitors (PPIs) are widely used to treat gastro-oesophageal reflux disease (GORD). However, the onset of action is considered slow and PPIs cannot completely block acid secretion at night. A new potassium-competitive acid blocker (P-CAB) can rapidly block acid secretion. However, whether this P-CAB can relieve GORD symptoms quickly and adequately soon after starting treatment is unknown.

AIM

To determine how rapidly vonoprazan and lansoprazole provide heartburn relief.

METHODS

Patients (n = 32) with endoscopically confirmed erosive oesophagitis who experienced heartburn at least once a week were randomised in a double-blind manner to receive either daily vonoprazan (20 mg) or lansoprazole (30 mg) before breakfast for 14 days. Day time and night time heartburn were assessed daily throughout the study using a five-point Likert scale. The primary endpoint was the first day of complete day and night heartburn relief for at least seven consecutive days. The ethics committees of the participating institutions approved the study protocol.

RESULTS

Heartburn was relieved sooner with vonoprazan than with lansoprazole (P < 0.05, log-rank test). Heartburn was completely relieved in 31.3% and 12.5% of patients on day 1 with vonoprazan and lansoprazole, respectively. Significantly more patients achieved complete nocturnal heartburn relief with vonoprazan than lansoprazole (P < 0.01). Both regimens were well tolerated.

CONCLUSIONS

Complete sustained heartburn relief was achieved sooner with vonoprazan than with lansoprazole during the first week of therapy. (UMIN000018776).

Potent Potassium-competitive Acid Blockers: A New Era for the Treatment of Acid-related Diseases

Conventional proton pump inhibitors (PPIs) are used as a first-line therapy to treat acid-related diseases worldwide. However, they have a number of limitations including slow onset of action, influence by cytochrome P450 polymorphisms, unsatisfactory effects at night, and instability in acidic conditions. Alternative formulations of conventional PPIs have been developed to overcome these problems; however, these drugs have only introduced small advantages for controlling acid secretion compared to conventional PPIs. Potassium-competitive acid blockers (P-CABs) were developed and have beneficial effects including rapid, long-lasting, and reversible inhibition of the gastric hydrogen potassium ATPase, the proton pump of the stomach. Vonoprazan was recently innovated as a novel, orally active P-CAB. It is currently indicated for the treatment of gastric and duodenal ulcers, reflux esophagitis, and prevention of low-dose aspirin- or nonsteroidal anti-inflammatory drug-related gastric and duodenal ulcer recurrence in Japan. Vonoprazan does not require enteric coating as it is acid-stable, and it can be taken without food because it is quickly absorbed. Vonoprazan accumulates in parietal cells under both acidic and neutral conditions. It does not require an acidic environment for activation, has long-term stability at the site of action, and has satisfactory safety and tolerability. Thus, vonoprazan may address the unmet medical need for the treatment of acid-related diseases.

Interchangeable Use of Proton Pump Inhibitors Based on Relative Potency

Although proton pump inhibitors (PPIs) are widely used, their relative potency and ideal dosing regimens remain unclear. We analyzed data from randomized clinical trials that performed pH testing in patients receiving solid-dose PPI formulations (omeprazole, esomeprazole, lansoprazole, pantoprazole, rabeprazole) for a minimum of 5 days. We used omeprazole equivalency and the surrogate biomarker, percentage time pH > 4 over a 24-hour period (pH4time), to compare PPI effectiveness for different PPIs given once, twice, or 3 times daily. We found that increasing strength of once-daily PPIs (9-64 mg omeprazole equivalents) increased pH4time linearly from approximately 10.0 to 15.6 hours; higher doses produced no further increase in pH4time. Increasing the frequency to twice-daily PPI increased pH4time linearly, from approximately 15.8 to 21.0 hours. Three-times daily PPIs performed similarly to twice-daily PPIs. The costs of PPIs varied greatly, but the cost variation was not directly related to potency. We conclude that PPIs can be used interchangeably based on potency. Using twice-daily PPIs is more effective in increasing efficacy increasing once-daily PPI dosage. Omeprazole and lansoprazole (30 mg) and 20 mg of esomeprazole rabeprazole are functionally equivalent.

Vonoprazan prevents ulcer recurrence during long-term NSAID therapy: randomised, lansoprazole-controlled non-inferiority and single-blind extension study

OBJECTIVE

To assess the non-inferiority of vonoprazan to lansoprazole for secondary prevention of non-steroidal anti-inflammatory drug (NSAID)-induced peptic ulcer (PU) and the safety of vonoprazan during extended use.

DESIGN

A phase 3, 24-week, multicenter, randomised, double-blind (DB), active-controlled study, followed by a phase 3, ≥28 week, multicenter, single-blind, parallel-group extension study (EXT) in outpatients (n=642) receiving long-term NSAID therapy who are at risk of PU recurrence. The patients received vonoprazan (10 mg or 20 mg) or lansoprazole 15 mg once daily. For DB, non-inferiority of the proportion of patients with recurrent PU within 24 weeks was analysed by Farrington and Manning test (significance level 2.5%, non-inferiority margin 8.3%; primary endpoint), recurrent PU within 12 weeks, bleeding and time-to-event of PU (secondary endpoint) and treatment-emergent adverse events (TEAEs). For EXT, TEAEs (primary endpoint), recurrent PU and safety (secondary) were assessed up to 104 weeks for patients in the extension study.

RESULTS

The non-inferiority of vonoprazan 10 mg and 20 mg to lansoprazole 15 mg was verified (percentage difference -2.2%,95% CI -6.2% to 1.8%, p<0.001; -2.1%,95% CI -6.1% to 2.0%, p<0.001, respectively). The proportion of patients with endoscopically confirmed recurrent PU within 24 weeks was 3.3%, 3.4% and 5.5%, for vonoprazan 10 mg, 20 mg and lansoprazole 15 mg, respectively. No significant safety concerns were identified.

CONCLUSION

The non-inferiority of vonoprazan (10 and 20 mg) was verified in patients receiving long-term NSAIDs in DB; it was effective and well tolerated in EXT for longer than 1 year, with a safety profile similar to lansoprazole (15 mg).

TRIAL REGISTRATION NUMBERS

NCT01452750, NCT01456260; Results.

Comparison of the early effects of vonoprazan, lansoprazole and famotidine on intragastric pH: a three-way crossover study

To promote symptom relief from acid-related diseases, a medicine with a rapid-onset effect is ideal. The aim of this study was to investigate the early inhibitory effect on gastric acid secretion after a single oral administration of vonoprazan, which represents a new class of proton pump inhibitors, and to compare this effect with those of lansoprazole and famotidine. Ten Helicobacter pylori (HP)-negative male subjects participated in this randomized, three-way crossover study. A single oral administration of vonoprazan (20 mg), lansoprazole (30 mg) or famotidine (20 mg) was performed, and the intragastric pH was continuously monitored for 6 h. Each drug was administered at least seven days apart. The average intragastric pH during the 6-h period after the administration of famotidine was higher than that after the administration of lansoprazole (median: 4.45 vs 2.65; p = 0.0284). A similar result was observed for vonoprazan and lansoprazole (median: 4.30 vs 2.65; p = 0.0322). In conclusions, oral administration of vonoprazan and famotidine in HP-negative healthy male subjects caused the intragastric pH to rise more quickly than did lansoprazole. (Trial Registration: UMIN000020989)

Sporadic Fundic Gland Polyps and Gastric Acid Suppression Level

BACKGROUND

Fundic gland polyps (FGPs) are a common endoscopic finding and are known to be associated with proton pump inhibitors (PPIs) use. It is not known if their prevalence is affected by gastric acidity levels. This study aimed to assess whether there is a correlation between FGPs and gastric acidity levels as identified on 24-hour ambulatory impedance-pH studies in patients on PPI therapy.

METHODS

We performed a review of 402 consecutive patients who take at least once daily PPI and underwent esophagogastroduodenoscopy with combined impedance-pH studies in the same setting (time and place) between January 2010 and December 2014. Patients were classified into 2 groups based on the presence or absence of biopsy-confirmed FGPs during endoscopy.

RESULTS

Of the 402 patients, 30 (7%) had FGPs. One of these polyps was found with low-grade dysplasia. There was no significant difference of the distributions of the [H⁺] in the FGPs versus the nonpolyp groups (P = 0.741). There was no significant difference between the 2 groups regarding PPI dose frequency regimens (once and twice) (P = 0.074). However, we found weak ordinal association with PPI duration (P = 0.01) (Spearman = 0.1).

CONCLUSIONS

FGPs are common endoscopic lesions. Incidence of dysplasia in FGPs is not only rare, but also of unknown clinical significance. Although they seem to be associated with PPIs, the mechanism remains unclear, as we found no correlation between the presence of FGPs and gastric acid control or PPI dose. Future studies would be useful to elucidate an alternate mechanism.

Proton pump inhibitor failure in gastro-oesophageal reflux disease: a perspective aided by the Gartner hype cycle

Some patients with gastro-oesophageal reflux disease (GORD) experience symptoms despite proton pump inhibitor (PPI) treatment. In the early years of their availability, these drugs were thought to be a highly effective treatment for GORD and realisation that symptom relief was often incomplete came as a disappointment. This review considers the evolution of thinking with the aid of the Gartner hype cycle - a graphical depiction of the process of innovation, evolution and adoption of new technologies. Acknowledging that over-simplistic concepts of GORD have been largely responsible for inflated expectations of PPI therapy is an important step forward in establishing how patients with persistent symptoms, despite PPIs, should be assessed and treated.

Rabeprazole and Psychiatric Symptoms

Objective:

To report the case of a patient who developed marked anxiety associated with episodes of panic attacks after starting rabeprazole therapy.

Case Summary:

An otherwise healthy 55-year-old woman was prescribed rabeprazole 20 mg/day administered in the morning tor persistent symptoms of dyspepsia. Ten days later, she presented with a 7 day history of marked anxiety associated with panic attacks, night terror (pavor nocturnus), episodic mental confusion, and attention deficit. Within 2 days of discontinuing rabeprazole, the patient recovered completely from the neuropsychiatric manifestations. Subsequent esomeprazole therapy did not cause psychiatric symptoms.

Discussion:

Rabeprazole-induced hypergastrinemia may have played a role in this neuropsychiatric adverse reaction. Several lines of evidence have indicated that gastrin-releasing peptide, whose release is mediated by proton pump inhibitor (PPI)–induced secretion of gastrin, is involved in regulating aspects of behavior that might be altered in disorders such as anxiety, depression, and dementia. The fact that rabeprazole has the highest capacity of inducing gastrin increase compared with other PPIs might explain why our patient's panic symptoms disappeared after switching to esomeprazole. Based on the Naranjo probability scale, rabeprazole was the probable cause of the adverse reaction.

Conclusions:

Specific studies are needed to investigate the potential role of PPI-induced hypergastrinemia in neuropsychiatrie adverse reactions.

Controlling on-demand gastric acidity in obese subjects: a randomized, controlled trial comparing a single dose of 20 mg rabeprazole and 20 mg omeprazole

Background

Obesity is associated with a risk of gastroesophageal reflux disease. The pharmacodynamic efficacy of proton pump inhibitors has not been specifically evaluated in obese subjects. The aim of this study was to compare the antisecretory response to a single oral dose of 20 mg rabeprazole, 20 mg omeprazole and placebo in obese subjects.

Methods

Gastric pH was monitored for 24 hours on three separate occasions in eighteen H. pylori-negative, asymptomatic obese subjects. Subjects were given omeprazole, rabeprazole or placebo in a randomized order and in a double-blind fashion. The main analysis criterion was 24-h percent of time post dose with intragastric pH above 3; secondary criteria were percentage of time above pH 4, median pH, [H+] concentrations and nocturnal acid breakthrough (NAB). Results were analyzed using linear mixed models and Wilks test comparing variances.

Results

24-h median [IQ] percentages of time with gastric pH above 3 and 4 were higher with rabeprazole than omeprazole (46 [37–55] vs. 30 [15–55] %, 9 [5-11] % for placebo) but the differences did not reach statistical significance (p = 0.11 and 0.24, respectively). Median acid concentrations were significantly lower with rabeprazole than with omeprazole and placebo (22 [14–53] vs. 54 [19–130] and 95 [73–170] mmoles/l, p < 0.01) for all periods. The number of NAB was significantly lower with rabeprazole than with omeprazole (median 1 [1,2] vs. 2 [1-3], p = 0.04). Variances of 24-h data (pH above 3 and 4, median pH, [H+] concentrations) were significantly lower with rabeprazole than with omeprazole (p < 0.0001).

Conclusions

In asymptomatic obese subjects the gastric antisecretory response to a single dose of rabeprazole and omeprazole was strong and not significantly different between drugs despite a significantly more homogeneous response with rabeprazole.

Trial registration

ClinicalTrial.gov: NCT01136317

Comparison of five-day Helicobacter pylori eradication regimens: rabeprazole-based and omeprazole-based regimens with and without omeprazole pretreatment

BACKGROUND

The onset of antisecretory activity of rabeprazole is faster than that of omeprazole.

OBJECTIVE

This study was performed to compare the efficacy of short-term rabeprazole-based triple therapy with that of omeprazole-based triple therapy and to determine the influence of omeprazole pretreatment in omeprazole-based short-term triple therapy.

METHODS

This was a 2-center, open-label, prospective, randomized study. Patients who tested positive for Helicobacter (formerly Campylobacter) pylori were randomized to one of three 5-day regimens: (1) rabeprazole 20 mg BID, amoxicillin 500 mg TID, and clarithromycin 400 mg BID (RAC group); (2) omeprazole 20 mg BID, amoxicillin 500 mg TID, and clarithromycin 400 mg BID without omeprazole pretreatment (OAC1 group); and (3) omeprazole 20 mg BID, amoxicillin 500 mg TID, and clarithromycin 400 mg BID with 5 days of omeprazole pretreatment 20 mg BID (OAC2 group). Eradication was assessed by (13)C-urea breath test and rapid urease test ∼1 month after completion of treatment. All patients who entered this study were included in the intent-to-treat (ITT) analysis, patients who completed the study were included in the per-protocol (PP) analysis, and patients who did not undergo the (13)C-urea breath test and rapid urease test were included in the all-patients-treated (APT) analysis.

RESULTS

A total of 120 patients (86 men, 34 women; mean [SD] age, 55.8 [14.3] years; range, 19-86 years) were assigned to the RAC, OAC1, or OAC2 group (40 patients in each group). ITT, PP, and APT eradication rates in the RAC group were 90%, 92%, and 90%, respectively; in the OAC1 group, 75%, 83%, and 75%; and in the OAC2 group, 85%, 90%, and 87%. These eradication rates were not significantly different between groups.

CONCLUSIONS

Eradication rates did not differ significantly between the three 5-day proton pump inhibitor-based triple therapies in this study population. However, 5-day rabeprazole-based triple therapy tends to be more effective than 5-day omeprazole-based triple therapy in the eradication of H pylori, and treatment with omeprazole before eradication therapy may improve the eradication rates of 5-day omeprazole-based therapy.

Rabeprazole: the role of proton pump inhibitors inHelicobacter pylorieradication

Proton pump inhibitors have become one of the cornerstones in the treatment of Helicobacter pylori infection. Rabeprazole (Pariet) is a substituted benzimidazole proton pump inhibitor with potent gastric acid suppression properties. Its high acid-base dissociation constant allows activation over a broader pH range, resulting in quick, irreversible binding to the H+/K+-ATPase pump, and a more rapid onset of action compared with omeprazole, lansoprazole and pantoprazole. Unlike other proton pump inhibitors, the metabolism of rabeprazole is primarily via a nonenzymatic reduction to the thioether derivative, and the cytochrome P450 isoenzyme 2C19 is only partly involved in its metabolism. The effect of genetic polymorphism in cytochrome P450 isoenzyme 2C19 on the pharmacokinetics and pharmacodynamics of rabeprazole is therefore limited. In humans, once-daily dosing of 5-40 mg of rabeprazole inhibits gastric acid secretion in a dose-dependent manner. In vitro studies have shown that rabeprazole possesses more potent antibacterial properties against the growth of H. pylori than other proton pump inhibitors. Furthermore, its thioether derivative has more potent inhibitory in vitro activity against the growth and motility of clarithromycin-resistant H. pylori than other proton pump inhibitors or commonly used antimicrobials. Despite these inherent favorable characteristics of rabeprazole, randomized controlled trials have largely shown equivalence amongst proton pump inhibitors when used with two antibiotics in the eradication of H. pylori, with cure rates of 75-89% on an intent-to-treat basis. However, rabeprazole appears to consistently achieve such comparable eradication rates even when used at reduced doses (10 mg twice daily) as part of clarithromycin-based triple therapy.

Absolute bioavailability and effect of formulation change, food, or elevated pH with rabeprazole on cobimetinib absorption in healthy subjects

Cobimetinib is a potent and highly selective inhibitor of MEK1/2. Since cobimetinib exhibited absorption variability in cancer patients, a series of single-dose studies in healthy subjects were conducted to determine absolute bioavailability and elucidate potential effects of formulation, food, and elevated gastric pH on cobimetinib bioavailability. Three crossover trials were performed with a 20 mg cobimetinib oral dose: absolute bioavailability using a 2 mg intravenous infusion (n = 13), relative bioavailability of tablets versus capsules and food effect (n = 20), and drug interaction with a proton pump inhibitor (20 mg of rabeprazole daily for 5 days prior to cobimetinib administration; n = 20). Absolute bioavailability of cobimetinib was 46.2% (24.2, CV %), likely due to metabolism rather than incomplete absorption. The mean systemic clearance of cobimetinib was low (11.7 L/h [28.2, CV %]). Administration of cobimetinib tablets with a high-fat meal delayed drug absorption (prolonged tmax) but had no statistically significant effect on cobimetinib exposure (Cmax and AUC0-∞). Tablet and capsule formulations of cobimetinib showed comparable exposures. Cobimetinib exhibited delayed absorption (tmax) in the presence of rabeprazole, with no statistically significant effects on drug exposure (Cmax and AUC0-∞) in the fasted state. In conclusion, cobimetinib oral absorption was not affected by change in formulation, food, or elevated gastric pH.

Gastroesophageal Reflux Disease Relief in Patients Treated with Rabeprazole 20 mg versus Omeprazole 20 mg: A Meta-Analysis

Background. Randomized controlled trials (RCTs) have been conducted comparing the efficacy of rabeprazole 20 mg or omeprazole 20 mg once daily for patients with erosive gastroesophageal reflux disease (GERD). Until now, no study has synthesized all available data examining this issue. Method. Medline, Embase, and the Cochrane central register of controlled trials were searched (through December 2012). Eligible RCTs recruited adults with erosive GERD and reported endoscopic and symptomatic relief rates at the last point of follow-up. The effect of rabeprazole versus omeprazole was reported as relative risk (RR) of relief with a 95% confidence interval (CI). Results. The search identified 605 citations, and six RCTs containing 1,895 patients were eligible. Endoscopic relief rates were not significantly different between rabeprazole 20 mg and omeprazole 20 mg in treatment trials of up to 8 weeks. Heartburn relief rates were significantly different between the two groups for 8-week treatment trials. Adverse events were not significantly different between the two groups for 8-week treatment trials. Conclusion. These data suggest that rabeprazole demonstrates a clinical advantage over omeprazole in symptomatic relief but no significant difference in endoscopic relief of erosive GERD for up to 8 weeks of treatment. Rabeprazole and omeprazole were both tolerated by GERD patients.

Gastroesophageal Reflux Disease Relief in Patients Treated with Rabeprazole 20 mg versus Omeprazole 20 mg: A Meta-Analysis

Background. Randomized controlled trials (RCTs) have been conducted comparing the efficacy of rabeprazole 20 mg or omeprazole 20 mg once daily for patients with erosive gastroesophageal reflux disease (GERD). Until now, no study has synthesized all available data examining this issue. Method. Medline, Embase, and the Cochrane central register of controlled trials were searched (through December 2012). Eligible RCTs recruited adults with erosive GERD and reported endoscopic and symptomatic relief rates at the last point of follow-up. The effect of rabeprazole versus omeprazole was reported as relative risk (RR) of relief with a 95% confidence interval (CI). Results. The search identified 605 citations, and six RCTs containing 1,895 patients were eligible. Endoscopic relief rates were not significantly different between rabeprazole 20 mg and omeprazole 20 mg in treatment trials of up to 8 weeks. Heartburn relief rates were significantly different between the two groups for 8-week treatment trials. Adverse events were not significantly different between the two groups for 8-week treatment trials. Conclusion. These data suggest that rabeprazole demonstrates a clinical advantage over omeprazole in symptomatic relief but no significant difference in endoscopic relief of erosive GERD for up to 8 weeks of treatment. Rabeprazole and omeprazole were both tolerated by GERD patients.

Rabeprazole and esomeprazole in mild-to-moderate erosive gastroesophageal reflux disease: A comparative study of efficacy and safety

Objective:

To compare the efficacy and safety of rabeprazole and esomeprazole in mild-to-moderate erosive gastroesophageal reflux disease (GERD).

Materials and Methods:

A randomized, single-blinded, outdoor-based clinical study was conducted on 60 patients of mild-to-moderate erosive GERD. After baseline clinical assessment and investigations, rabeprazole (40 mg) was prescribed to 30 patients and esomeprazole (40 mg) to another 30 patients for 4 weeks. The efficacy variables were change in GERD symptom scoring, endoscopic findings, and Quality of Life in Reflux and Dyspepsia (QOLRAD) scoring over 4 weeks.

Result:

Heartburn, acid regurgitation, and overall GERD symptom scoring (P = 0.01) were significantly decreased with rabeprazole in comparison to esomeprazole. The comparative study of all five domains of the QOLARD questionnaire including overall scoring revealed a statistically significant improvement in the rabeprazole group. Endoscopic findings in the rabeprazole group showed an absolute improvement of 30% and relative improvement of 55% over esomeprazole. Both the drugs were well tolerated having no significant difference in the incidence of adverse effects.

Conclusion:

Rabeprazole (40 mg) is a better choice for mild-to-moderate GERD compared with esomeprazole (40 mg) because of its better efficacy and safety profile.

Dissociative disorder induced by clarithromycin combined with rabeprazole in a patient with gastritis

Clarithromycin and rabeprazole are both valued for their safety profile. Very few cases of adverse side-effects related to these drugs, when given individually, have been reported; serious side-effects of clarithromycin in combination with rabeprazole have never been reported. The present case reports on a 51-year-old woman with gastritis who received clarithromycin combined with rabeprazole for Helicobacter pylori infection. After taking 500 mg clarithromycin and 10 mg rabeprazole orally she displayed acute psychotic symptoms of dissociative disorder, including: impairment of orientation and attention; the feeling of dreaming; disintegration of thinking; stereotyped speech; flattened emotion; amnesia. Routine blood investigations, computed tomography scans and electroencephalography showed no abnormalities. All symptoms disappeared without antipsychotic treatment ≈ 48 h after she had taken the two drugs. Combining clarithromycin with rabeprazole might increase the risk of neurotoxicity, particularly in susceptible individuals. This should be a concern in clinical practice.

Early effects of oral administration of omeprazole and roxatidine on intragastric pH

OBJECTIVE

The ideal medication for the treatment of acid-related diseases, e.g., peptic ulcers, stress-related gastric bleeding, functional dyspepsia, and gastroesophageal reflux disease, should have a rapid onset of action to promote hemostasis and relieve the symptoms. The aim of our study was to investigate the inhibitory effects on gastric acid secretion of a single oral administration of a proton pump inhibitor, omeprazole 20 mg, and an H(2)-receptor antagonist, roxatidine 75 mg.

METHODS

Ten Helicobacter pylori-negative male subjects participated in this randomized, two-way crossover study. Intragastric pH was monitored continuously for 6 h after single oral administration of omeprazole 20 mg and roxatidine 75 mg. Each administration was separated by a 7-d washout period.

RESULTS

During the 6-h study period, the average pH after administration of roxatidine was higher than that after administration of omeprazole (median: 4.45 vs. 2.65; P=0.0367). Also during the 6-h study period, a longer duration of maintenance at pH above 2, 5, and 6 was observed after administration of roxatidine 75 mg than after administration of omeprazole 20 mg (median: 90.6% vs. 55.2%, P=0.0284; 43.7% vs. 10.6%, P=0.0125; 40.3% vs. 3.3%, P=0.0125; respectively).

CONCLUSIONS

In Helicobacter pylori-negative healthy male subjects, oral administration of roxatidine 75 mg increased the intragastric pH more rapidly than that of omeprazole 20 mg.

Pharmacokinetics and tolerability of rabeprazole in children 1 to 11 years old with gastroesophageal reflux disease

BACKGROUND

The pharmacokinetics of rabeprazole after a single oral dose and once-daily administration for 5 consecutive days was characterized in children 1 to 11 years old with gastroesophageal reflux disease (GERD).

PATIENTS AND METHODS

The initial 8 patients received rabeprazole sodium (hereafter referred to as rabeprazole) 0.14 mg/kg (part 1); the next 20 patients were randomized to receive 0.5 or 1 mg/kg (part 2) to target concentrations in plasma expected to be safe and effective. Pharmacokinetic parameters of rabeprazole and the thioether metabolite were calculated using noncompartmental methods. Subjective evaluations of GERD severity, rabeprazole short-term effectiveness, palatability, and safety were also characterized.

RESULTS

Rabeprazole concentrations increased in a dose-dependent manner. Little or no accumulation was observed after repeated administration. The results suggest that formation of the thioether is an important metabolic pathway in young patients, which is consistent with adults. Plasma area under the concentration-time curve values of rabeprazole and the metabolite were poorly correlated with individual age and body weight. Furthermore, oral rabeprazole clearance values (not adjusted for weight) were similar to historical adult data. However, weight-adjusted values were higher for the pediatric patients, and approximately 2 to 3 times the milligram per kilogram dose of rabeprazole in these children was necessary to achieve comparable concentrations in adults. Subjective evaluations demonstrated an improvement of GERD symptoms in most patients after rabeprazole treatment.

CONCLUSIONS

Palatability of the formulation was reported to be good or excellent. Rabeprazole was well tolerated, with no notable differences in safety among the dose groups.

Guidance on the use of over-the-counter proton pump inhibitors for the treatment of GERD

OBJECTIVE

The aim of this paper was to develop a guideline on the over-the-counter management of gastroesophageal reflux disease with proton pump inhibitors (i.e. omeprazole).

SETTING

A meeting of internationally renowned gastroenterologists in January 2009, in Berlin, Germany.

METHODS

An expert panel group of gastroenterologists convened to develop a consensus-based algorithm for pharmacists for over-the-counter (OTC) treatment with proton pump inhibitors (PPIs). Key considerations were the short-term safety and efficacy of PPIs, and the extent of the risk to the sufferer, owing to the treatment not being controlled by a physician. Main outcome measures A consensus-based treatment algorithm for the OTC management of gastroesophageal reflux disease and evidence-based guidance on the use of OTC PPIs.

RESULTS

As defined by the treatment algorithm, the pharmacist should first confirm the diagnosis based on the presence of typical symptoms and secondly, as a result, rule out general practitioner referral. The third step focuses on the nature, severity and frequency of the symptoms--the patients who might have the highest benefit from a short course (14 days) of OTC PPIs are those with less than three episodes of heartburn and/or acid regurgitation per week. Patients who have three or more episodes per week can use the OTC PPIs but should also be encouraged to visit a physician, and those who already have a diagnostic work-up can use proton pump inhibitors as rescue treatment if they are known responders. Guidance for pharmacists, in the form of questions and answers, summarises the current published clinical experience with PPIs in terms of their efficacy and safety, and optimal treatment schedule. Conclusions Gastroesophageal reflux disease imposes a considerable burden on sufferers. Owing to their accepted efficacy and safety, PPIs are becoming popular as OTC options for the treatment of gastroesophageal reflux disease symptoms such as heartburn and acid regurgitation. Effective self-management of gastroesophageal reflux disease with OTC PPIs, e.g. omeprazole, could lead to lasting freedom from symptoms and improved quality of life for sufferers.

Clinical trial: inhibitory effect of revaprazan on gastric acid secretion in healthy male subjects

BACKGROUND AND AIM

Revaprazan is a novel acid pump antagonist. The aim of this study was to investigate the inhibitory effect of revaprazan on gastric acid secretion in healthy male subjects.

METHODS

In a double-blind, three-way cross-over study, 30 healthy male volunteers were randomized to 100, 150 or 200 mg of oral revaprazan daily for 7 days. Serum gastrin concentration was measured, and 24-h intragastric pH was recorded at baseline and on days 1 and 7 of each administration period. Serial blood samples were processed for pharmacokinetics.

RESULTS

Median intragastric pH over 24 h and mean percentage time that pH was > 4 increased in a dose-dependent manner and were significantly higher on days 1 and 7 compared with baseline in all groups (P < 0.05). The antisecretory effect of revaprazan was rapid and nearly maximal on day 1 in all groups. Serum gastrin levels were rapidly normalized by 100 and 150 mg/day of revaprazan on days 1 and 7, but were significantly higher in the 200 mg/day revaprazan group. The pharmacokinetic effect was rapidly absorbed and eliminated on days 1 and 7 in all groups.

CONCLUSIONS

Revaprazan rapidly and effectively inhibits gastric acid secretion in healthy male subjects. Therefore, revaprazan can be used as an effective drug for acid-related disease.

Relationship between the Acid-Inhibitory Effects of Two Proton Pump Inhibitors and CYP2C19 Genotype in Japanese Subjects: A Randomized Two-Way Crossover Study

This two-way crossover study investigated possible differences between the proton pump inhibitors, omeprazole and rabeprazole, in their effect on gastric acid secretion in Japanese subjects with differing cytochrome P450, family 2, subfamily C, polypeptide 19 (CYP2C19) genotypes. A total of 23 Helicobacter pylori-negative healthy volunteers received omeprazole 20 mg/day and rabeprazole 10 mg/day. Each drug treatment was given for a continuous 7-day period allocated in random order, with an interval of at least 1 week between drug treatment periods to allow for wash-out. Intragastric pH was measured on days 1 and 7. Overall median intragastric pH levels at 7 and 8 h after the first administration were significantly higher with omeprazole. There was no significant difference in intragastric pH in homozygous extensive metabolizers, whereas intragastric pH was significantly higher with omeprazole in combined data from heterozygous extensive metabolizers and poor metabolizers at 6, 7 and 8 h after the first drug administration. There were no significant differences in intragastric pH between omeprazole and rabeprazole irrespective of genotype on day 7 of administration. In conclusion, on day 1 the time to onset of the antisecretory action of 20 mg/day omeprazole was more rapid than that of 10 mg/day rabeprazole in Japanese individuals who have a higher incidence of the CYP2C19 poor metabolizer genotype, however by day 7 no difference in antisecretory effect was found, regardless of genotype.

Safety of the long-term use of proton pump inhibitors

The proton pump inhibitors (PPIs) as a class are remarkably safe and effective for persons with peptic ulcer disorders. Serious adverse events are extremely rare for PPIs, with case reports of interstitial nephritis with omeprazole, hepatitis with omeprazole and lansoprazole, and disputed visual disturbances with pantoprazole and omeprazole. PPI use is associated with the development of fundic gland polyps (FGP); stopping PPIs is associated with regression of FGP. In the absence of Helicobacter pylori infection, the long-term use of PPIs has not been convincingly proven to cause or be associated with the progression of pre-existing chronic gastritis or gastric atrophy or intestinal metaplasia. Mild/modest hypergastrinemia is a physiological response to the reduction in gastric acid secretion due to any cause. The long-term use of PPIs has not been convincingly proven to cause enterochromaffin-like cell hyperplasia or carcinoid tumors. PPIs increase the risk of community acquired pneumonia, but not of hospital acquired (nosocomial) pneumonia. There is no data to support particular care in prescribing PPI therapy due to concerns about risk of hip fracture with the long-term use of PPIs. Long-term use of PPIs does not lead to vitamin B12 deficiencies, except possibly in the elderly, or in persons with Zollinger-Ellison Syndrome who are on high doses of PPI for prolonged periods of time. There is no convincingly proven data that PPIs increase the risk of Clostridium difficile-associated diarrhea in persons in the community. The discontinuation of PPIs may result in rebound symptoms requiring further and even continuous PPI use for suppression of symptoms. As with all medications, the key is to use PPIs only when clearly indicated, and to reassess continued use so that long-term therapy is used judiciously. Thus, in summary, the PPIs are a safe class of medications to use long-term in persons in whom there is a clear need for the maintenance of extensive acid inhibition.

Rabeprazole 20 mg for erosive esophagitis-associated symptoms in a large, community-based study: additional results

PURPOSE

To provide additional efficacy data in patients treated with rabeprazole through week 4, and to validate sustained relief of gastroesophageal reflux disease symptoms through week 8 as well as to further analyze rabeprazole safety in patients with wide-ranging demographic and clinical characteristics.

RESULTS

Patients in this study (N = 2,449) demonstrated significant overall improvement versus baseline (P < 0.001). Substantial symptom relief was seen throughout 8 weeks of treatment. By week 4, complete relief of daytime and nighttime heartburn, belching, regurgitation, and dysphagia was observed in 87.5, 90.7, 50.7, 77.6, and 75.1% of patients, respectively. Improvements were seen in rabeprazole-treated patients (<65 or >or=65 years) with a range of baseline symptom severities and across different racial groups. Rabeprazole was well tolerated.

CONCLUSIONS

In patients with endoscopy-confirmed erosive esophagitis treated with once-daily rabeprazole 20 mg, prompt and continuing improvements were seen in daytime and nighttime heartburn, belching, regurgitation, and dysphagia.

Effects of dexlansoprazole MR, a novel dual delayed release formulation of a proton pump inhibitor, on plasma gastrin levels in healthy subjects

Dexlansoprazole MR is a modified release formulation of a proton pump inhibitor being developed for the treatment of acid-related disorders. The purpose of this study is to characterize the plasma gastrin (PG) profile associated with administration of dexlansoprazole MR. Forty-two healthy subjects receive dexlansoprazole MR 90 mg, dexlansoprazole MR 120 mg, and lansoprazole 30 mg once daily for 5 days in a randomized, open-label, 3-period crossover study with at least 14-day washout intervals. Twenty-four-hour PG profiles are obtained at baseline (day -1 of period 1) and on days 1 and 5 in each period. Fasting PG levels are determined on days 8 and 12 in periods 1 and 2. On day 1, 24-hour PG levels increase from baseline to a similar extent with all regimens. On day 5, 24-hour PG levels with both dexlansoprazole MR regimens increase further and to a similar extent and are slightly higher than PG levels with lansoprazole. For all regimens, fasting PG levels on days 5 and 6 are higher than baseline levels (P<.05) and start to decrease by day 8, returning to near baseline at day 12. In this study, dexlansoprazole MR administration results in moderate increases in PG, similar to lansoprazole, which return to baseline levels within 7 days post dosing.

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.

Motilides: a long and winding road: lessons from mitemcinal (GM-611) on diabetic gastroparesis

Mitemcinal (GM-611) is a macrolide motilin receptor agonist with acid-resistance and without antibiotic activity. Since ABT-229 (a first generation of motilin receptor agonist) had failed to demonstrate symptomatic relief in functional dyspepsia and diabetic gastroparesis, there is a controversy for which of prokinetics or relaxants is clinically beneficial. Currently, oral mitemcinal has been focused on diabetic gastroparesis under clinical development. It showed to accelerate gastric-emptying in diabetic animals and in patients with gastroparesis. The latest double-blind, placebo-controlled study demonstrated to be effective at improving diabetes-related gastroparesis symptoms. A sub-group analysis, which included patients with BMI < 35 kg/m2 and hemoglobin A1c < 10%, there were significantly more symptomatic relieves in the 10 mg mitemcinal group than in the placebo group. The frequency of adverse events did not differ between groups. Mitemcinal shows promise in the subset of patients who should be confirmed in future studies.

Comparative study of omeprazole, lansoprazole, pantoprazole and esomeprazole for symptom relief in patients with reflux esophagitis

AIM: To clarify whether there is any difference in the symptom relief in patients with reflux esophagitis following the administration of four Proton pump inhibitors (PPIs).

METHODS: Two hundred and seventy-four patients with erosive reflux esophagitis were randomized to receive 8 wk of 20 mg omeprazole (n = 68), 30 mg of lansoprazole (n = 69), 40 mg of pantoprazole (n = 69), 40 mg of esomeprazole (n = 68) once a day in the morning. Daily changes in heartburn and acid reflux symptoms in the first 7 d of administration were assessed using a six-point scale (0: none; 1: mild; 2: mild-moderate; 3: moderate; 4: moderate-severe; 5: severe).

RESULTS: The mean heartburn score in patients treated with esomeprazole more rapidly decreased than those receiving other PPI. Complete resolution of heartburn was also more rapid in patients treated with esomeprazole for 5 d compared with omeprazole (P = 0.0018, P = 0.0098, P = 0.0027, P = 0.0137, P = 0.0069, respectively), lansoprazole (P = 0.0020, P = 0.0046, P = 0.0037, P = 0.0016, P = 0.0076, respectively), and pantoprazole (P = 0.0006, P = 0.0005, P = 0.0009, P = 0.0031, P = 0.0119, respectively). There were no significant differences between the four groups in the rate of endoscopic healing of reflux esophagitis at week 8.

CONCLUSION: Esomeprazole may be more effective than omeprazole, lansoprazole, and pantoprazole for the rapid relief of heartburn symptoms and acid reflux symptoms in patients with reflux esophagitis.

Relative potency of proton-pump inhibitors-comparison of effects on intragastric pH

AIM

Comparative potency of proton-pump inhibitors (PPIs) is an important clinical issue. Most available trials have compared the different PPIs at one or a few selected specific dosages, making it difficult to derive quantitative equivalence dosages. Here we derived PPI dose equivalents based on a comprehensive assessment of dose-dependent effects on intragastric pH.

METHODS

All available clinical studies reporting the effects of PPIs on mean 24-h intragastric pH were sought from electronic databases including Medline. Studies included were restricted to those targeting the Caucasian population, and healthy volunteers or gastroesophageal reflux disease (GERD) patients. The dose-effect relationships for mean 24-h intragastric pH and for percentage of time with pH > 4 in 24 h were analyzed for each PPI using pharmacodynamic modeling with NONMEM and a model integrating all available data.

RESULTS

Fifty-seven studies fulfilled the inclusion criteria. Based on the mean 24-h gastric pH, the relative potencies of the five PPIs compared to omeprazole were 0.23, 0.90, 1.00, 1.60, and 1.82 for pantoprazole, lansoprazole, omeprazole, esomeprazole, and rabeprazole, respectively. Compared with healthy volunteers, patients with GERD needed a 1.9-fold higher dose and Helicobacter pylori-positive individuals needed only about 20% of the dose to achieve a given increase in mean 24-h intragastric pH.

CONCLUSION

The present meta-analysis provides quantitative estimates on clinical potency of individual PPIs that may be helpful when switching between PPIs and for assessing the cost-effectiveness of specific PPIs. However, our estimates must be viewed with caution because only a limited dose range has been tested and not exactly the same study conditions were applied for the different substances.

Comparative efficacy of rabeprazole and pantoprazole in the control of nocturnal Acid output and intragastric acidity

BACKGROUND/AIMS

Nocturnal reflux is a largely undiagnosed and unmanaged condition predisposing to multiple esophageal complications. We evaluated the effects of rabeprazole and pantoprazole on nocturnal intragastric pH and gastric acid output during Day 1 of therapy following the consumption of standard meals.

METHODS

The study had a double-blinded, randomized, two-way crossover design, and involved 15 patients with a history of mild reflux. Following an overnight fast, patients were given either rabeprazole (20 mg) or pantoprazole (40 mg) prior to the first of three standard Western meals. They then underwent overnight continuous intragastric pH monitoring and gastric acid output measurement. The drug effect was analyzed using a two-treatment, two-period crossover mixed model.

RESULTS

The percentage of time during which the mean intragastric pH was greater than 4.0 and gastric acid output was less than 2.0 was higher for oral rabeprazole (p<0.05). The inhibition of acid output was greater for rabeprazole at almost all time points. Furthermore, the mean time-matched pH values differed significantly over the first 8.3 hours (p<0.05).

CONCLUSIONS

On day 1, oral rabeprazole inhibited acid output to a greater extent and for a longer period than pantoprazole, and the intragastric pH was significantly higher for rabeprazole than for pantoprazole over the first 8.3 hours.

Early effects of Lansoprazole orally disintegrating tablets on intragastric pH in CYP2C19 extensive metabolizers

AIM: To compare rabeprazole (RPZ; 10 mg) with Lansoprazole orally disintegrating tablets (LPZ; 30 mg OD) in terms of antisecretory activity and blood drug concentration after a single dose.

METHODS: Eight H pylori-negative cytochrome P450 (CYP) 2C19 extensive metabolizers were assigned to receive a single oral dose of RPZ 10 mg or LPZ 30 mg OD. Twelve hour intragastric pH monitoring was performed on the day of treatment. Blood samples were also collected after the administration of each drug.

RESULTS: LPZ 30 mg OD induced a significantly earlier rise in blood drug concentration than RPZ 10 mg; consequently, LPZ 30 mg OD induced a significantly earlier rise in median pH in the third and fourth hours of the study.

CONCLUSION: In H pylori-negative CYP2C19 extensive metabolizers, LPZ 30 mg OD induced a significantly faster inhibition of gastric acid secretion than RPZ 10 mg.

Endoscopic analysis of gastric ulcer after one week's treatment with omeprazole and rabeprazole in relation to CYP2C19 genotype

In Japanese healthy CYP2C19 extensive metabolizers, rabeprazole 10 mg shows a faster onset of action and stronger inhibition of acid secretion than does omeprazole 20 mg on the first 3 days of administration. We evaluated gastric ulcer improvement after 1 week's treatment with rabeprazole or omeprazole in relation to CYP2C19 polymorphism. A 6-mm rubber disc was placed temporarily at the side of the ulcer for measurement of the ulcer area. The improvement ratios of ulcer area in homozygous extensive metabolizers (homoEMs), heterozygous extensive metabolizers (heteroEMs) and poor metabolizers (PMs) treated with rabeprazole 10 mg were 60.8, 65.0 and 55.3%, respectively, and these values are not significantly different. Corresponding values with omeprazole 20 mg were 46.3, 61.7 and 63.2%, respectively, and the value of homoEMs was significantly smaller than that of heteroEMs. The improvement ratios with rabeprazole in homoEMs and heteroEMs were significantly greater than that with omeprazole in homoEMs.

Rapid protection of the gastroduodenal mucosa against aspirin-induced damage by rabeprazole

BACKGROUND

The ability of a proton pump inhibitor to reduce or prevent NSAID-induced gastroduodenal damage during the first 24 h has not been tested.

AIM

To determine, whether oral rabeprazole, administered 5 h before the initiation of therapeutic dosing of aspirin protects the gastroduodenal mucosa.

METHODS

Normal subjects were randomized into two groups - one received rabeprazole, 20 mg at 07:00 hours and the other placebo, before initiation of aspirin 650 mg at 12:00 hours, and then q4 h for 3 days. Upper endoscopic examinations were performed on all subjects at baseline, 24 and 72 h after initiation of aspirin. Gastroduodenal mucosal damage was scored.

RESULTS

Thirty subjects were compliant with study medications and underwent three endoscopic examinations. Salicylate concentrations were similar for the placebo and the rabeprazole groups at all times. On rabeprazole, the Lanza scores were significantly lower compared with placebo at 24 h (1.3 +/- 0.26 vs. 2.1 +/- 0.26, P < 0.05) and at 72 h (1.3 +/- 0.29 vs. 2.3 +/- 0.28, P < 0.05). Gastric antral erosion counts were less with rabeprazole than placebo at 24 (4.1 +/- 1.3 vs. 7.6 +/- 2.0, P > 0.05) and 72 h (5.3 +/- 1.8 vs. 8.0 +/- 1.5; P > 0.05).

CONCLUSIONS

Rabeprazole, initiated 5 h before the start of therapeutic dosing with aspirin, decreased Lanza scores and antral erosion counts at 24 h. These findings suggest that prophylaxis with rabeprazole could start concurrently with aspirin administration.

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.

Dual therapy with high doses of rabeprazole and amoxicillin versus triple therapy with rabeprazole, amoxicillin, and metronidazole as a rescue regimen for Helicobacter pylori infection after the standard triple therapy

BACKGROUNDS AND AIMS

Development of safe and effective rescue regimens for eradication failure of Helicobacter pylori infection by standard regimens is an urgent task. We designed the prospective study to compare the efficacy of two rescue regimens after eradication failure by the standard triple therapy.

METHODS

One hundred and thirty-two patients in whom eradication of H. pylori infection failed initial triple therapy with lansoprazole 30 mg b.i.d, amoxicillin 750 mg b.i.d. and clarithromycin 400 mg b.i.d. for 1 week were randomized to either the 1-week triple therapy with rabeprazole 10 mg b.i.d., amoxicillin 750 mg b.i.d., and metronidazole 250 mg b.i.d. (RAM) or the 2-week dual therapy with rabeprazole 10 mg q.i.d. and amoxicillin 500 mg q.i.d. (RA). Eradication of H. pylori was judged by (13)C-urea breath test 1 month later.

RESULTS

The intention-to-treat and per-protocol-based eradication rates were 92.4% (95% CI: 83.2-97.5) and 95.3% (95% CI: 86.9-99.0) for the RAM therapy and 90.9% (95% CI: 81.2-96.6) and 93.8% (95% CI: 84.8-98.3), respectively, for the RA therapy (P > 0.2 for both). No clinically recognizable adverse events were observed with either regimen.

CONCLUSION

RA as well as RAM therapy are safe and effective rescue regimens for H. pylori infection after eradication failure by the standard triple therapy.

Effects of mitemcinal (GM-611), an acid-resistant nonpeptide motilin receptor agonist, on the gastrointestinal contractile activity in conscious dogs

The effects of mitemcinal (GM-611) on the gastrointestinal contractile activity were investigated using chronically implanted force transducers in conscious dogs and were compared with the effects of porcine motilin (pMTL), EM-523 and EM-574. In the interdigestive state, intravenous and oral administration of mitemcinal, EM-523 and EM-574 induced the gastrointestinal contractile activity in a manner similar to pMTL. The contractile activity caused by mitemcinal was suppressed by continuous intravenous infusion of a motilin receptor antagonist. In the digestive state, intravenous and oral administration of mitemcinal, EM-523 and EM-574 also stimulated the gastrointestinal contractile activity. Mitemcinal, EM-523 and EM-574 given intravenously increased the gastric contractile activity in a similar dose range; however, mitemcinal was approximately 10 times more potent than EM-523 and EM-574 when administered orally in the digestive state. These results indicate that the mitemcinal-induced gastrointestinal contractile activity operates via motilin receptors and possesses a higher activity than EM-523 and EM-574 when administered orally in conscious dogs in the digestive state. Mitemcinal may therefore be useful in the treatment of several gastrointestinal disorders involving dysmotility, such as gastroparesis and functional dyspepsia, even when administered orally.

A novel method to radiolabel gastric retentive formulations for gamma scintigraphy assessment

PURPOSE

To develop a robust radiolabeling technique to enable evaluation of difficult to radiolabel gastric retentive formulations using gamma scintigraphy. The use of a successful radiolabel will allow accurate assessment of the gastric residence time of the formulations.

MATERIALS AND METHODS

The retention of two radionuclides, indium ((111)In) and samarium ((153)Sm), with and without further processing to improve radiolabel performance were evaluated in simulated gastric pH in vitro. The most successful formulation from the in vitro screening was further evaluated in preclinical and clinical studies.

RESULTS

In vitro evaluation revealed significant radionuclide leakage at pH 1.5 for most radiolabeling attempts. Radionuclide leakage at pH 4.5 was less pronounced. The most successful radiolabel was formulated by adsorbing indium chloride onto activated charcoal, followed by entrapment in a cellulose acetate polymer melt. This provided the best radiolabel retention under both pH conditions in vitro. The radiolabel also proved to be successful during preclinical and clinical evaluations, allowing evaluation of gastric retention performance as well as complete gastrointestinal transit.

CONCLUSION

A simple, yet robust radiolabel was developed for gastric retentive formulations to be evaluated pre-clinically or in a clinical setting by entrapping the radionuclide in an insoluble polymer through a simple polymer melt process.

Comparison of the effects of single and repeated oral doses of lansoprazole and rabeprazole on ambulatory 24-hour intragastric pH in healthy volunteers

BACKGROUND

As the comparative pharmacokinetics and pharmacodynamics of lansoprazole and rabeprazole have not previously been studied, we set out in this study to compare the pharmacokinetics and pharmacodynamics of single and repeated daily doses of lansoprazole 15 mg and 30 mg with those of rabeprazole 10 mg and 20 mg.

METHODS

This was an open-label, randomised, crossover, two-centre study in 72 healthy volunteers. Each subject received each of the four treatments for 5 days, with 2-week washout periods. Continuous 24-hour intragastric pH and pharmacokinetics were studied on days 1 and 5.

RESULTS

Mean 24-hour pH and percentage time for pH > 4 were not significantly different between lansoprazole 30 mg and rabeprazole 20 mg. Mean 24-hour pH and percentage time for pH > 4 were significantly greater after lansoprazole 30 mg and rabeprazole 20 mg than after lansoprazole 15 mg and rabeprazole 10 mg, respectively. Lansoprazole resulted in greater acid suppression during hours 0-5 on days 1 and 5, whereas rabeprazole had greater suppression during hours 11-24 on day 5. Time to maximum plasma concentration was significantly shorter for lansoprazole on both days.

CONCLUSION

Lansoprazole had a consistently faster onset of action, whereas rabeprazole had a greater effect during the evening hours after 5 days of administration.

Human pharmacogenomic variations and their implications for antifungal efficacy

Pharmacogenomics is defined as the study of the impacts of heritable traits on pharmacology and toxicology. Candidate genes with potential pharmacogenomic importance include drug transporters involved in absorption and excretion, phase I enzymes (e.g., cytochrome P450-dependent mixed-function oxidases) and phase II enzymes (e.g., glucuronosyltransferases) contributing to metabolism, and those molecules (e.g., albumin, A1-acid glycoprotein, and lipoproteins) involved in the distribution of antifungal compounds. By using the tools of population genetics to define interindividual differences in drug absorption, distribution, metabolism, and excretion, pharmacogenomic models for genetic variations in antifungal pharmacokinetics can be derived. Pharmacogenomic factors may become especially important in the treatment of immunocompromised patients or those with persistent or refractory mycoses that cannot be explained by elevated MICs and where rational dosage optimization of the antifungal agent may be particularly critical. Pharmacogenomics has the potential to shift the paradigm of therapy and to improve the selection of antifungal compounds and adjustment of dosage based upon individual variations in drug absorption, metabolism, and excretion.

Effect of rabeprazole and omeprazole on the onset of gastro-oesophageal reflux disease symptom relief during the first seven days of treatment

OBJECTIVE

Gastro-oesophageal reflux disease (GORD) symptoms have a significant impact on patients' well-being. Onset of symptom relief is therefore an important consideration in GORD treatment. The primary objective was to compare the efficacy of rabeprazole (20 mg) and omeprazole (20 mg) regarding onset of heartburn control during the first 7 days of treatment in patients with erosive oesophagitis. Secondary objectives included maintenance of sustained heartburn control, control of other GORD symptoms (e.g. acid regurgitation, epigastric pain, dysphagia), effect on quality of life, patient satisfaction with treatment, and adverse events.

MATERIAL AND METHODS

In this multicentre, randomized, parallel-group, double-blind, comparative study, performed in Europe and Iceland, patients with endoscopically confirmed erosive oesophagitis were randomized to receive once-daily treatment with rabeprazole 20 mg (n=358) or omeprazole 20 mg (n=359) for 7 days. Symptoms were recorded (scored on a 5-point Likert scale) twice daily by the patients on their diary cards.

RESULTS

Median time to reach heartburn control was 1.5 days for both the rabeprazole and omeprazole groups (p<0.43). The results were similar between treatments for other study parameters. Both treatments were well tolerated.

CONCLUSIONS

Unlike previous studies, no significant differences were found between treatments with rabeprazole (20 mg) and omeprazole (20 mg) in this study. Further studies are needed to evaluate the potential benefit of fast-acting proton-pump inhibitors, such as rabeprazole, with respect to onset of symptom control in erosive GORD.

Does Helicobacter pylori infection influence response rate or speed of symptom control in patients with gastroesophageal reflux disease treated with rabeprazole?

OBJECTIVE

The findings of several studies suggest that proton-pump inhibitors (PPIs) suppress gastric acid more effectively in Helicobacter pylori-infected (Hp +) than in non-infected (Hp -) patients, but there has been no evaluation of the short-term clinical response.

MATERIAL AND METHODS

Results of the first week of treatment with rabeprazole in Hp+ and Hp- patients with gastroesophageal reflux disease (GERD) were compared in a large prospective open-label, multicenter, cohort study in general and specialized practices. GERD patients were recruited on the basis of either typical symptoms alone or endoscopic results, assessed for H. pylori infection and treated with rabeprazole (20 mg). Heartburn and regurgitation symptoms were assessed daily during the first 7 days. Outcome parameters were calculated for both symptoms and compared between Hp+ and Hp- patients.

RESULTS

Data on 1548 patients (74.5% Hp-, 25.5% Hp + ) were available. Mean heartburn and regurgitation scores decreased during the first week. For both symptoms, more than 70% of the patients had "adequate" symptom relief at day 5, and more than 80% at day 7. "Complete" symptom relief was reached in more than 70% of patients. Mean onset of adequate symptom control was about 4 days. In Hp+ and Hp- patients there was no difference in response for any of the parameters.

CONCLUSIONS

Among patients treated with rabeprazole in clinical practice, H. pylori infection or its absence has no effect on the speed or degree of GERD symptom relief. Infected patients and non-infected patients can therefore be treated with a similar dose. When treating heartburn with rabeprazole, physicians do not need to consider the patient's H. pylori status and most patients (>80%) have adequate symptom relief after just a few days of treatment.

Comparison of the efficacy of rabeprazole 10 mg and omeprazole 20 mg for the healing rapidity of peptic ulcer diseases

AIM

Rabeprazole has been known to inhibit H(+)/K(+)-ATPase more rapidly than omeprazole, the prototype proton pump inhibitor (PPI). The aim of this study was to demonstrate equivalence between low-dose rabeprazole 10 mg and omeprazole 20 mg for the healing rapidity of active peptic ulcer and for improvement of symptoms. Also, the effect of CYP2C19 genotypes on ulcer healing rapidity was investigated.

METHODS

A total of 112 patients with active peptic ulcer were randomized to receive either rabeprazole 10 mg q.d. or omeprazole 20 mg q.d. for 6 weeks. The remaining ratios (%) and complete healing of the ulcer were determined by endoscopy at 1 week and 6 weeks of treatment. The severity of ulcer pain was also investigated during treatment. CYP2C19 genotype was determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The remaining ratio of peptic ulcers after 1 week and the complete healing rate after 6 weeks in the rabeprazole versus omeprazole group were 45.5% versus 50.3% (P = 0.475) and 80.6% versus 87.0% (P = 0.423), respectively. CYP2C19 genotypes had no effect on the remaining ratio of peptic ulcers after 1 week and the healing rate of peptic ulcers after 6 weeks in both groups. The proportions of patients with symptom improvement or resolution were comparable between the two groups.

CONCLUSION

Low-dose rabeprazole 10 mg has a similar efficacy for the healing rapidity of active peptic ulcer disease and symptom improvement compared with standard-dose omeprazole 20 mg.