Rabeprazole: a review of its use in acid-related gastrointestinal disorders

Effects of proton pump inhibitor (PPI) use on migraine - a critical review

BACKGROUND

Proton pump inhibitor (PPI) drugs are widely used and are among the most significant achievements of modern pharmacology. Their primary purpose is treating and preventing gastric acid-related disorders. Migraine and PPI intake are prevalent, and many people are affected by both. In the last few years, a potential link between PPI intake and the development of headaches-especially migraine-has come to increased attention. In this review, we critically examine the scientific data concerning the co-occurrence of these two entities.

FINDINGS

There seems to be a possible link between the use of PPIs and the occurrence of headache, especially migraine, suggesting a pathophysiological connection on several levels. Moreover, PPI use is only partially without side effects, even if these may not occur immediately. Whether the relation is causative or merely co-existential is currently not yet clear. The influence of genetics, environment, gut microbiome, medication intake and evolution of headache is multidirectional.

CONCLUSION

A relation between the prevalence of migraine and the use of PPIs on a population and personal level seems likely. Although PPIs have many advantages, they should be prescribed with caution, especially in patients who suffer from headaches and migraine. In this narrative review, we aim to critically evaluate existing data and offer a potential approach to accurately identify any connections and interactions, leading to a better understanding of how these conditions may influence each other.

Production of an O-desmethylated product, a major human metabolite, of rabeprazole sulfide by bacterial P450 enzymes

Rabeprazole is a common type of proton pump inhibitor (PPI) used to treat various peptic disorders. Unlike most PPI drugs, rabeprazole is spontaneously reduced to rabeprazole sulfide (thioether) when it is given to patients. As a result, rabeprazole sulfide is considered one of the active metabolites of rabeprazole. Rabeprazole sulfide is mainly metabolized to desmethyl rabeprazole sulfide by CYP2C19 and CYP2D6 in people. However, the pharmacological efficacy and safety of desmethyl rabeprazole sulfide have not yet been investigated. Its usage is challenging due to the high cost associated with the drug. In this study, we found CYP102A1 mutants that can produce desmethyl rabeprazole sulfide as a major metabolite of rabeprazole sulfide. The chemical characteristics of the major product were confirmed using high-performance liquid chromatography, LC-mass spectrometry, and nuclear magnetic resonance spectroscopy. CYP102A1 mutants R47L/F87V/L188Q, R47L/F87V/L188Q/A335V/Q359R, and R47L/F87V/L188Q/I254V/D351E showed kcat values of 39, 93, and 88 min-1, respectively, for O-desmethylation of rabeprazole sulfide. Furthermore, the highest concentration of desmethyl rabeprazole sulfide product from 2 mM rabeprazole sulfide at optimal conditions was obtained in bacterial whole-cell biotransformation with the R47L/F87V/L188Q mutant, reaching 0.63 mM at 4-h incubation. In conclusion, we present a platform that facilitates the efficient and sustainable production of the desmethylated product from rabeprazole sulfide for use in the biopharmaceutical industry.

Rabeprazole Promotes Vascular Repair and Resolution of Sepsis-Induced Inflammatory Lung Injury through HIF-1α

There are currently no effective treatments for sepsis and acute respiratory distress syndrome (ARDS). The repositioning of existing drugs is one possible effective strategy for the treatment of sepsis and ARDS. We previously showed that vascular repair and the resolution of sepsis-induced inflammatory lung injury is dependent upon endothelial HIF-1α/FoxM1 signaling. The aim of this study was to identify a candidate inducer of HIF-1α/FoxM1 signaling for the treatment of sepsis and ARDS. Employing high throughput screening of a library of 1200 FDA-approved drugs by using hypoxia response element (HRE)-driven luciferase reporter assays, we identified Rabeprazole (also known as Aciphex) as a top HIF-α activator. In cultured human lung microvascular endothelial cells, Rabeprazole induced HIF1A mRNA expression in a dose-dependent manner. A dose-response study of Rabeprazole in a mouse model of endotoxemia-induced inflammatory lung injury identified a dose that was well tolerated and enhanced vascular repair and the resolution of inflammatory lung injury. Rabeprazole treatment resulted in reductions in lung vascular leakage, edema, and neutrophil sequestration and proinflammatory cytokine expression during the repair phrase. We next used Hif1a/Tie2Cre knockout mice and Foxm1/Tie2Cre knockout mice to show that Rabeprazole promoted vascular repair through HIF-1α/FoxM1 signaling. In conclusion, Rabeprazole is a potent inducer of HIF-1α that promotes vascular repair and the resolution of sepsis-induced inflammatory lung injury via endothelial HIF-1α/FoxM1 signaling. This drug therefore represents a promising candidate for repurposing to effectively treat severe sepsis and ARDS.

Selective Targeting of Human and Animal Pathogens of the Helicobacter Genus by Flavodoxin Inhibitors: Efficacy, Synergy, Resistance and Mechanistic Studies

Antimicrobial resistant (AMR) bacteria constitute a global health concern. Helicobacter pylori is a Gram-negative bacterium that infects about half of the human population and is a major cause of peptic ulcer disease and gastric cancer. Increasing resistance to triple and quadruple H. pylori eradication therapies poses great challenges and urges the development of novel, ideally narrow spectrum, antimicrobials targeting H. pylori. Here, we describe the antimicrobial spectrum of a family of nitrobenzoxadiazol-based antimicrobials initially discovered as inhibitors of flavodoxin: an essential H. pylori protein. Two groups of inhibitors are described. One group is formed by narrow-spectrum compounds, highly specific for H. pylori, but ineffective against enterohepatic Helicobacter species and other Gram-negative or Gram-positive bacteria. The second group includes extended-spectrum antimicrobials additionally targeting Gram-positive bacteria, the Gram-negative Campylobacter jejuni, and most Helicobacter species, but not affecting other Gram-negative pathogens. To identify the binding site of the inhibitors in the flavodoxin structure, several H. pylori-flavodoxin variants have been engineered and tested using isothermal titration calorimetry. An initial study of the inhibitors capacity to generate resistances and of their synergism with antimicrobials commonly used in H. pylori eradication therapies is described. The narrow-spectrum inhibitors, which are expected to affect the microbiota less dramatically than current antimicrobial drugs, offer an opportunity to develop new and specific H. pylori eradication combinations to deal with AMR in H. pylori. On the other hand, the extended-spectrum inhibitors constitute a new family of promising antimicrobials, with a potential use against AMR Gram-positive bacterial pathogens.

Does Rabeprazole Sodium Alleviate the Anti-diabetic Activity of Linagliptin? Drug-Drug Interaction Analysis by In vitro and In vivo Methods

Drug interaction has turned into the preeminent regarding issues for a prescriber during polypharmacy. The foremost objective of this research was to form a complex between linagliptin and rabeprazole sodium by in vitro interactions. The interactions between the drugs have been examined by monitoring some chromatographic and spectroscopic analyses viz. TLC, HPLC, FT-IR, UV, Job's plot, conductometric titrations, and Ardon's spectrophotometric strategy. Rabeprazole sodium formed a stable complex with linagliptin, which was ensured from the insight of these analytical data. The developed complex's bright spot was clearly watched in the TLC plate. The retention time (R_t) of the formed complex was 5.303 min, where the R_t were 3.364 and 3.103 min for linagliptin and rabeprazole sodium, respectively, in HPLC chromatograms. In FT-IR and UV spectra of the formed complex revealed some disappearance of characteristic peaks that affirmed the complexation. All of the variations of the spectrophotometric and chromatographic properties from the antecedent drugs indicated the drug-drug interaction. Another crucial fact for the experimental aim was to affirm the assumed drug interaction by in vivo model examination. The assessment of anti-diabetic property on alloxan-induced Swiss albino mice proved significant in vivo interaction between the drugs. It was outlined from the animal study that the hypoglycemic activity of linagliptin might be significantly affected due to the complex formation of the drug with a proton pump inhibitor (PPI). Nonetheless, it is the primary outcome of the interaction, which recommends the bigger in vivo study or clinical monitoring on the human model.

Proton pump inhibitor-related headaches: A nationwide population-based case-crossover study in Taiwan

Background

Headaches resulting from proton pump inhibitor (PPI) use could cause discontinuation of PPI in as many as 40% of patients who experience such headaches. Previous studies focusing on acute headache risk from PPI use are rare and limited to clinical trials of a single PPI.

Objectives

To investigate the association between PPI use and headache with a nationwide population-based case-crossover study.

Methods

Records containing the first diagnosis of any headache, including migraine and tension-type headaches, were retrieved from Taiwan National Health Insurance Database (1998–2010). We compared the rates of PPI use for cases and controls during time windows of 7, 14, and 28 days. The adjusted self-matched odds ratios (ORs) and 95% confidence intervals (CIs) from a conditional logistic regression model were used to determine the association between PPI use and headache.

Results

Overall, 314,210 patients with an initial diagnosis of any headache during the study period were enrolled. The adjusted ORs for headache risk after PPI exposure were calculated for three time periods (within 7 days = 1.41, p = 0.002, 95% CI 1.14–1.74; within 14 days = 1.36, p < 0.001, 95% CI 1.16–1.59; within 28 days = 1.20, p = 0.002, 95% CI 1.07–1.35). Subgroup analyses showed female patients had an increased risk of headache. Among PPIs, lansoprazole and esomeprazole had the highest risks of headache incidence, which were similar to that of nitrates.

Conclusion

PPI usage is associated with an increased risk for acute headache. Female patients and use of lansoprazole or esomeprazole present the greatest risks of headache.

CYP2C19 genotypes in the pharmacokinetics/pharmacodynamics of proton pump inhibitor-based therapy of Helicobacter pylori infection

IMPORTANCE OF THE FIELD

Proton pump inhibitors (PPIs) are potent gastric acid inhibitors. Therapies with a PPI and antibiotics are used to cure Helicobacter pylori (H. pylori) infection, which is closely related to many gastrointestinal diseases. Most PPIs are mainly metabolized by cytochrome 2C19 (CYP2C19). The genetic polymorphisms of CYP2C19 may lead to the differences in pharmacokinetics (PK), pharmacodynamics (PD) and clinical efficacy of PPIs.

AREAS COVERED IN THIS REVIEW

The roles of PPIs on the eradication of H. pylori are summarized. The impact f CYP2C19 polymorphism on the PK and PD of PPIs is addressed and related to the present status of therapy for H. pylori infection. The opinions on the strategy of PPIs-based therapies of H. pylori infection are provided.

WHAT THE READER WILL GAIN

Update the factors that may influence the PPIs-based therapies of H. pylori infection.

TAKE HOME MESSAGE

The eradication rates of H. pylori infection are significantly different between patients who are CYP2C19 extensive metabolizers and poor metabolizers, partly because of the differences in the PK and PD of PPIs. Nonetheless, the differences can be improved by adjusting the regimens of PPIs and using antibiotics that have less H. pylori-resistance.

Rabeprazole: a review of its use in the management of gastric acid-related diseases in adults

Rabeprazole (Aciphex, Alfence, Pariet) is a proton pump inhibitor (PPI) used for the treatment of adults with conditions requiring a reduction of gastric acid secretion such as erosive or ulcerative gastro-oesophageal reflux disease (GORD), non-erosive reflux disease (NERD), duodenal and gastric ulcers, and pathological hypersecretory conditions including Zollinger-Ellison syndrome (ZES). It is also used as part of combination therapy for the eradication of Helicobacter pylori, a pathogen frequently implicated in the development of gastric and duodenal ulcers. Rabeprazole has a well established efficacy and safety profile in the treatment of gastric acid-related diseases. Rabeprazole is a useful, well tolerated and cost-effective option for the treatment of GORD, NERD, peptic ulcer and other gastric acid-related diseases (including ZES), and provides an appropriate alternative to other currently available PPIs, with the added benefits of having a consistent efficacy profile and low drug interaction potential due to its predominantly nonenzymatic metabolism.

New method for long-term monitoring of intragastric pH

AIM: Consecutive monitoring of intragastric pH using the Bravo^® capsule.

METHODS: We put threads through a Bravo^® capsule and then affixed it to the gastric wall by endoscopic hemoclipping in seven subjects. Study data were uploaded to a computer via Datalink every 48 h. In this way, repeated monitoring of intragastric pH was undertaken.

RESULTS: All subjects were able to monitor gastric pH over a 1-wk period, and five for > 2 wk. No complications were encountered during the monitoring. After pH monitoring, we safely retrieved the capsule endoscopically.

CONCLUSION: Clipping a Bravo^® capsule onto the gastric wall enabled long-term intragastric pH monitoring. This is a methodological report of pH monitoring over a period of > 2 wk.

Review of immediate-release omeprazole for the treatment of gastric acid-related disorders

Immediate-release omeprazole (Zegerid, Santarus) is the first immediate-release oral proton pump inhibitor to reach the market. As a powder formulation for oral suspension, it is indicated for the treatment of gastroesophageal reflux disease, erosive oesophagitis, duodenal ulcer and gastric ulcer, and is the only proton pump inhibitor approved for the reduction of risk of upper gastrointestinal bleeding in critically ill patients. Administration of immediate-release omeprazole at bedtime results in a rapid and sustained elevation of gastric pH, and seems to provide better night time control of gastric acidity than that observed with conventional morning dosing of delayed-release proton pump inhibitors. The immediate-release formulation may provide a good treatment option for patients who require flexible dosing, quick onset of action and nocturnal gastric acid control.

Potent Gastric Acid Inhibition in Helicobacter pylori Eradication

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

A Pharmacological Approach to Gastric Acid Inhibition

Proton pump inhibitors have changed our approach to gastric acid-related diseases. They are much more potent acid inhibitors than H2-antagonists and exhibit a sophisticated mechanism of action. The present review analyses the general pharmacology of proton pump inhibitors and differentiates the specific characteristics of the various compounds that belong to this family. Special emphasis has been placed in describing the clinical implications of such differences and the potential importance for adverse effects.

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

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

Pharmacokinetic and pharmacodynamic evaluation of a novel proton pump inhibitor, YH1885, in healthy volunteers

To evaluate the pharmacokinetic and pharmacodynamic characteristics of YH1885, a novel proton pump inhibitor, a single-blind, randomized, placebo-controlled, dose-rising, parallel-group study was conducted in 46 healthy volunteers. The volunteers were randomly allocated to single dose groups of 60 mg, 100 mg, 150 mg, 200 mg, and 300 mg (6 subjects per dose, including 2 placebos) or to multiple-dose groups of 150 mg and 300 mg (once-daily dosing for 7 days; 8 subjects per dose, including 2 placebos). The multiple-dose study was conducted separately after the single-dose study. YH1885 was administered orally after overnight fasting. Serial blood samples, urine samples, and pharmacodynamic measurements were taken. Drug concentrations in plasma and urine were determined by liquid chromatography/mass spectrometry (LC/MS). Pharmacodynamic changes were evaluated by ambulatory intragastric pH monitoring and by serial measurements of serum gastrin concentrations. Assessments of safety and tolerability also were made. Plasma concentrations of YH1885 reached peak levels 1.3 to 2.5 hours after single-dose administration and then declined monoexponentially with a terminal half-life (t(1/2)) of 2.2 to 2.4 hours in dosage groups up to 200 mg in the single-dose study. YH1885 showed linear pharmacokinetic characteristics, and little accumulation occurred after multiple administrations. The parent drug was not detected in urine. Dose-related pharmacological effects were obvious for dose groups of 150 mg and higher in the single-dose study. The mean intragastric pH and the percentage of time at pH>4 were significantly increased. The onset of drug effect was rapid, and maximal effects were observed on the first day of administration during multiple dosing. Serum gastrin levels also showed rapid increases during dosing but with a weak dose-effect relationship. Neither serious nor dose-limiting adverse effects were observed. YH1885 was found to be safe and well tolerated and effectively inhibited acid secretion with dose-dependent increases in intragastric pH. The acid-suppressing efficacy of YH1885 needs to be further evaluated in patients with gastric acid-related diseases.

Time-dependent amplified pharmacokinetic and pharmacodynamic responses of rabeprazole in cytochrome P450 2C19 poor metabolizers

STUDY OBJECTIVES

To determine the pharmacokinetic and pharmacodynamic rationale for the optimum regimen of rabeprazole in the treatment of Helicobacter pylori infection in patients who are cytochrome P450 (CYP) 2C19 poor metabolizers or extensive metabolizers.

DESIGN

Prospective, multiple-dose pharmacokinetic and pharmacodynamic study.

SETTING

University-affiliated medical center in Taiwan.

SUBJECTS

Twelve healthy volunteers (aged 20-30 yrs) who were identified as CYP2C19 poor metabolizers (six subjects) or extensive metabolizers (six).

INTERVENTION

Each subject received rabeprazole 20 mg twice/day for 3 consecutive days and once/day on the fourth day.

MEASUREMENTS AND MAIN RESULTS

Pharmacokinetic and pharmacodynamic parameters were compared between CYP2C19 poor and extensive metabolizers on day 1 and day 4 of dosing. The mean +/- SD values of area under the concentration-time curve of rabeprazole and rabeprazole thioether were significantly higher in poor metabolizers than in extensive metabolizers on day 1 (5357 +/- 883 vs 1131 +/- 512 ng x hr/ml and 1703 +/- 432 vs 561 +/- 358 ng x hr/ml, respectively; p<0.001) and on day 4 (5601 +/- 669 vs 1619 +/- 778 ng x hr/ml and 1914 +/- 378 vs 511 +/- 360 ng x hr/ml, respectively; p<0.001). However, no significant difference was noted between day 1 and day 4 of dosing within the same genotype groups. Only CYP2C19 poor metabolizers had significantly higher plasma gastrin levels on day 4 compared with those levels on day 1 (p<0.05). The pharmacokinetic-pharmacodynamic relationship of rabeprazole appears to be time dependent.

CONCLUSION

The pharmacokinetic and pharmacodynamic data suggest that CYP2C19 poor metabolizers might be subject to advantageous conditions, especially after day 4, for treating H. pylori infection with rabeprazole.

Systematic review: Rabeprazole-based therapies in Helicobacter pylori eradication

AIM

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

METHODS

Studies evaluating rabeprazole plus antibiotics were considered. Only randomized trials comparing rabeprazole and other proton pump inhibitors with antibiotics, and differing only in the proton pump inhibitor, were included in the meta-analysis. Electronic and manual bibliographic searches were conducted. The percentage (weighted mean) of successful eradication was calculated. Meta-analysis was performed by combining the odds ratios (OR) of the individual studies.

RESULTS

The eradication rates were as follows: 14-day rabeprazole-amoxicillin, 73%; rabeprazole-amoxicillin-clarithromycin for 3, 5, 7 and 10 days, 44%, 72%, 78% and 75%, respectively; low-dose rabeprazole (20 mg/day), amoxicillin and clarithromycin for 7 days, 81%; high-dose rabeprazole (40 mg/day), amoxicillin and clarithromycin for 7 days, 75%; 7-day rabeprazole-clarithromycin-nitroimidazole, 85%. Twelve comparative studies were included in the meta-analysis. The eradication rate with rabeprazole plus antibiotics was 79%; it was 77% with other proton pump inhibitors (OR = 1.15; 95% confidence interval, 0.93-1.42). Sub-analysis comparing rabeprazole at low doses (10 mg b.d.) with other proton pump inhibitors at standard doses (omeprazole 20 mg b.d. or lansoprazole 30 mg b.d.) showed no differences.

CONCLUSIONS

Rabeprazole achieves similar H. pylori eradication rates to omeprazole and lansoprazole when co-prescribed with antibiotics. Low doses of rabeprazole (10 mg b.d.), when administered with two antibiotics, may be sufficient to eradicate H. pylori infection.

Review of esomeprazole in the treatment of acid disorders

Esomeprazole (Nexium, AstraZeneca) is the (S)-isomer of omeprazole and the first proton pump inhibitor to be developed as an optical isomer. Esomeprazole has an improved pharmacokinetic profile, resulting in increased systemic exposure and less interindividual variability compared with omeprazole, and more effective suppression of gastric acid production compared with other proton pump inhibitors. In several large, double-blind, randomised trials, significantly higher rates of endoscopically-confirmed healing of erosive oesophagitis and resolution of heartburn have been achieved in patients with gastro-oesophageal reflux disease receiving 8 weeks of esomeprazole 40 mg o.d. compared with those receiving omeprazole 20 mg o.d. or lansoprazole 30 mg o.d. In the maintenance of healed erosive oesophagitis, esomeprazole 10, 20 or 40 mg o.d. was significantly more effective than placebo in two 6-month, randomised, double-blind trials. Additionally, esomeprazole 20 mg o.d. was more effective than lansoprazole 15 mg in the maintenance of healed erosive oesophagitis in another 6-month, randomised, double-blind trial. Healing of oesophagitis was also effectively maintained by esomeprazole 40 mg o.d. in a 12-month non-comparative trial. Esomeprazole 20 or 40 mg o.d. effectively relieved heartburn in patients with gastro-oesophageal reflux disease without oesophagitis in two 4-week, placebo-controlled trials. Clinical trials have shown that triple therapy with esomeprazole 40 mg o.d. in combination with amoxicillin and clarithromycin produced Helicobacter pylori eradication rates similar to those obtained using triple therapy involving twice-daily dosing with other proton pump inhibitors. Esomeprazole is well-tolerated, with a spectrum and incidence of adverse events similar to those associated with omeprazole.

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

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

Characteristics of diarrhoea in 10,008 users of lansoprazole in daily practice: which co-factors contribute?

PURPOSE

Diarrhoea is one of the most frequently reported adverse events during proton pump inhibitor use in any setting. Because of the limited available information, this study was set up with the aim of assessing the incidence and characteristics of diarrhoea and to investigate possible associated co-factors in proton pump inhibitor users in daily practice.

METHODS

Data were used from a prospective, observational study in which 10,008 lansprazole users were followed over time (1994-1998). The study was designed according to the SAMM guidelines. A nested case-control design was used to compare proton pump inhibitor users reporting diarrhoea with those reporting no diarrhoea.

RESULTS

The frequency of diarrhoea was 3.7% and the incidence density 10.7 per 1000 patients months of proton pump inhibitor use. The diarrhoea was most commonly loose and occurred on average 4.4 times per day. The analysis of co-factors revealed that patients with concomitant use of oral antibiotics and patients reporting neurological and/or dermatological adverse events, were at risk of developing diarrhoea during proton pomp inhibitor use.

CONCLUSIONS

In conclusion, diarrhoea was as frequently reported in our study as in clinical trials and observational data of lansoprazole users. We found the concomitant use of oral antibiotics and the reporting of certain other adverse events to be associated with the reporting of diarrhoea during lansoprazole use. Although a relationship with the proton pump inhibitor intake seemed very plausible, we recommend that use of concomitant medicines as a cause of diarrhoea must be taken into consideration in lansoprazole users.

Determinants of headache in lansoprazole users in The Netherlands: results from a nested case-control study

OBJECTIVE

During proton pump inhibitor (PPI) use, in clinical trials, headache is one of the most frequently reported adverse events (frequency 1.3 to 8.8%), while results of one observational study indicate that headache is the fifth most frequently reported adverse event (incidence densities 2.5 to 4.6 per 1000 patient-months of exposure). However, there are no observational studies performed regarding the occurrence and features of headache during use of PPIs in daily practice. For this reason this study was set up with the aim to assess the incidence and characteristics of headache and to investigate possible associated co-factors in PPI users in daily practice.

DESIGN

Data were used from a prospective, observational study in which 10 008 lansoprazole users were followed over time. The study was designed according to the Safety Assessment of Marketed Medicines guidelines. A nested case-control design was used to compare PPI users reporting headache or not.

RESULTS

The frequency of headache was 2.5% in users of lansoprazole and the incidence density was 7.2 per 1000 patient-months of PPI lansoprazole use. Two-thirds of patients with headache had tension headache and one-third had migraine. The analysis of co-factors revealed that women, patients with previous use of analgesics and patients reporting several adverse events, were at risk to develop headache during PPI use. Patients with headache also, significantly more often, reported diarrhoea, nausea and dizziness. A discontinuation of PPI therapy resulted in a cessation or reduction of the headache in 80.0% (20 of 25).

CONCLUSIONS

As can be expected, headache was reported less frequently in this study compared with clinical trials with lansoprazole. The incidence density was comparable with other observational data of lansoprazole and omeprazole users. Besides several commonly accepted co-factors such as female gender and a history of analgesic use, we also found the reporting of other adverse events to be associated with the reporting of headache during lansoprazole use. The cessation of headache after a discontinuation of use of the PPI and the observed dose relationship suggested that headache was indeed an adverse effect of lansoprazole use.

Esomeprazole: a review of its use in the management of acid-related disorders

Esomeprazole (S-isomer of omeprazole), the first single optical isomer proton pump inhibitor, generally provides better acid control than current racemic proton pump inhibitors and has a favourable pharmacokinetic profile relative to omeprazole. In a large well designed 8-week trial in patients (n >5000) with erosive oesophagitis, esomeprazole recipients achieved significantly higher rates of endoscopically confirmed healed oesophagitis than those receiving lansoprazole. Respective healed oesophagitis rates with once-daily esomeprazole 40mg or lansoprazole 30mg were 92.6 and 88.8%. Overall, esomeprazole was also better than omeprazole, although these differences were not always statistically significance. Ninety-two to 94% of esomeprazole recipients (40mg once daily) achieved healed oesophagitis versus 84 to 90% of omeprazole recipients (20mg once daily). Esomeprazole was effective across all baseline grades of oesophagitis; notably, relative to lansoprazole, as baseline severity of disease increased, the difference in rates of healed oesophagitis also increased in favour of esomeprazole. Resolution of heartburn was also significantly better with esomeprazole 40mg than with these racemic proton pump inhibitors. Long-term (up to 12 months) therapy with esomeprazole effectively maintained healing in these patients. Once-daily esomeprazole 20 or 40mg for 4 weeks resolved symptoms in patients with symptomatic gastro-oesophageal reflux disease (GORD) without oesophagitis. Symptoms were effectively managed in the long-term with symptom-driven on-demand esomeprazole (20 or 40mg once daily). Eradicating Helicobacter pylori infection is considered pivotal to successfully managing duodenal ulcer disease. Seven days' treatment (twice-daily esomeprazole 20mg plus amoxicillin 1g and clarithromycin 500mg) eradicated H. pylori in >/=86% of patients (intention-to-treat), a rate that was similar to equivalent omeprazole-based regimens. Esomeprazole is generally well tolerated, both as monotherapy and in combination with antimicrobial agents, with a tolerability profile similar to that of other proton pump inhibitors. Few patients discontinued therapy because of treatment-emergent adverse events (<3% of patients), with very few (<1%) drug-related serious adverse events reported.

CONCLUSIONS

Esomeprazole is an effective, well tolerated treatment for managing GORD and for eradicating H. pylori infection in patients with duodenal ulcer disease. In 8-week double-blind trials, esomeprazole healed oesophagitis and resolved symptoms in patients with endoscopically confirmed erosive oesophagitis and overall, provided better efficacy than omeprazole. Notably, in a large (n >5000 patients) double-blind trial, esomeprazole 40mg provided significantly better efficacy than lansoprazole in terms of healing rates and resolution of symptoms. Long-term therapy with esomeprazole maintained healed oesophagitis in these patients. Esomeprazole also proved beneficial in patients with symptomatic GORD without oesophagitis. Thus, esomeprazole has emerged as an option for first-line therapy in the management of acid-related disorders.

Patient perceptions of a proton pump inhibitor therapeutic interchange program across the continuum of care

OBJECTIVE

To determine if participation in a hospital-based proton pump inhibitor (PPI) therapeutic interchange program resulted in differences in patient perceptions related to clinical and humanistic outcomes.

METHODS

A quasiexperimental repeated-measures study compared patients' perceptions in two groups (111 patients) at hospital admission, discharge, 3-4 days after discharge, and 2-3 weeks after discharge to detect differences across the continuum of care. Patient awareness of the hospital-based interchange also was examined. Clinical and quality-of-life outcomes were measured by using a condition-specific instrument modified for use with patients. Satisfaction and expectations were measured by using extent-of-agreement measures. Group 1 (60 patients) was prescribed omeprazole before admission, switched to lansoprazole during hospitalization, and discharged taking omeprazole. Group 2 (51 patients) was prescribed lansoprazole before admission and continued taking lansoprazole throughout hospitalization and after discharge. Patients who were unable to communicate or who had a substantial change in severity of illness (not attributable to gastrointestinal disorders) during the study were excluded.

RESULTS

No significant differences were found between groups 1 and 2 for clinical outcomes, quality of life, extent to which expectations were met, or satisfaction at the four time periods. Nineteen (36%) of 53 surveyed patients in group 1 were not aware that their therapy had been interchanged while in the hospital.

CONCLUSION

Patient-perceived outcomes and expectations of therapy across the continuum of care were not affected by a hospital-based PPI therapeutic interchange program.

Rabeprazole: an update of its use in acid-related disorders

Rabeprazole is an inhibitor of the gastric proton pump. It causes dose-dependent inhibition of acid secretion. In 8-week studies, among patients with gastro-oesophageal reflux disease (GORD), rabeprazole 20 mg/day or 10mg twice daily was as effective as omeprazole and superior to ranitidine in the healing of GORD. Symptom relief with rabeprazole was superior to that provided by placebo and ranitidine and similar to omeprazole. In long-term trials rabeprazole 10 mg/day was similar to omeprazole 20 mg/day in a 2-year study and superior to placebo in 1-year studies, in both the maintenance of healing and prevention of symptoms in patients with healed GORD. In nonerosive GORD, 4-week studies have shown rabeprazole to be more effective than placebo in relieving heartburn and various other gastrointestinal symptoms. Data among patients with Barrett's oesophagus suggest rabeprazole 20 mg/day may be more effective than placebo in maintaining healing of associated oesophagitis after 1 year of treatment. One-week triple Helicobacter pylori eradication therapy with rabeprazole plus clarithromycin and amoxicillin achieved eradication rates of > or =85%. Rabeprazole is as effective as omeprazole and lansoprazole when included as part of a triple-therapy regimen for the eradication of H. pylori. Eradication rates of >90% were achieved when rabeprazole 20 to 40 mg/day was included as part of a quadruple eradication regimen. As monotherapy for peptic ulcer healing and symptom relief, 4- to 8-week studies have shown rabeprazole 10 to 40 mg/day to be superior to placebo and ranitidine and have similar efficacy to omeprazole. Preliminary 1-year data among 16 patients with Zollinger-Ellison syndrome suggest rabeprazole 60 to 120 mg/day can resolve and prevent the recurrence of symptoms and endoscopic lesions associated with this condition. In clinical trials of up to 2 years' duration the tolerability of rabeprazole is similar to that of placebo, ranitidine and omeprazole. Common adverse events assigned to rabeprazole have been diarrhoea, headache, rhinitis, nausea, pharyngitis and abdominal pain. Histological changes and increases in serum gastrin levels were unremarkable and typical of proton pump inhibitors. No dosage adjustment is necessary in renal and mild to moderate hepatic impairment.

CONCLUSION

Rabeprazole is a well tolerated proton pump inhibitor. It has proven efficacy in healing, symptom relief and prevention of relapse of peptic ulcers and GORD and can form part of effective H. pylori eradication regimens. It is an important alternative to H(2) antagonists and an additional treatment option to other proton pump inhibitors in the management of acid-related disorders.

Pharmacokinetic considerations in the eradication of Helicobacter pylori

As Helicobacter pylori plays an important role in the aetiopathogenesis of peptic ulcer, therapeutic strategies aimed at maintaining long term remission have shifted from the control of intragastric pH to targeting H. pylori. According to recent international guidelines the clinical goals--rapid ulcer healing and prevention of relapse--can be best accomplished by combination therapy consisting of an antisecretory drug (proton pump inhibitor or ranitidine) and 2 antimicrobial agents (preferable amoxicillin, clarithromycin or metronidazole). When applying such multidrug regimens, possible synergy between the agents suggests that pharmacokinetic considerations might help to improve H. pylori eradication rates, which should be above 85 to 90% on an intention-to-treat basis. The present review summarises the pharmacokinetic properties and interaction potential of all drugs presently used in the various H. pylori eradication regimens, with emphasis on particular patient populations such as the elderly and those with renal impairment. The drugs considered are omeprazole, lansoprazole, pantoprazole, rabeprazole, ranitidine and ranitidine bismutrex, bismuth salts, amoxicillin, clarithromycin, azithromycin, roxithromycin, metronidazole, tinidazole and tetracycline. When addressing the clinically important questions of the efficacy, safety and costs of the recommended regimens, the impact of drug disposition on H. pylori eradication should not be neglected.