Lansoprazole. An update of its pharmacological properties and clinical efficacy in the management of acid-related 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.

The Effects of Omeprazole on the Neuron-like Spiking of the Electrical Potential of Proteinoid Microspheres

This study examines a new approach to hybrid neuromorphic devices by studying the impact of omeprazole-proteinoid complexes on Izhikevich neuron models. We investigate the influence of these metabolic structures on five specific patterns of neuronal firing: accommodation, chattering, triggered spiking, phasic spiking, and tonic spiking. By combining omeprazole, a proton pump inhibitor, with proteinoids, we create a unique substrate that interfaces with neuromorphic models. The Izhikevich neuron model is used because it is computationally efficient and can accurately simulate the various behaviours of cortical neurons. The results of our simulations show that omeprazole-proteinoid complexes have the ability to affect neuronal dynamics in different ways. This suggests that they could be used as adjustable components in bio-inspired computer systems. We noticed a notable alteration in the frequency of spikes, patterns of bursts, and rates of adaptation, especially in chattering and triggered spiking behaviours. The findings indicate that omeprazole-proteinoid complexes have the potential to serve as adaptable elements in neuromorphic systems, presenting novel opportunities for information processing and computation that have origins in neurobiological principles. This study makes a valuable contribution to the expanding field of biochemical neuromorphic devices and establishes a basis for the development of hybrid bio-synthetic computational systems.

Proton Pump Inhibitors: More Indigestion than Relief?

Proton pump inhibitors (PPIs) are widely prescribed to treat a number of gastrointestinal (GI) disorders due to excessive acid production. While effective and safe, adverse renal effects have been increasingly described in epidemiological literature. The most well-documented adverse renal outcome is acute interstitial nephritis; however, association with overall acute kidney injury has also been recently reported. Recently, two observational studies have linked PPI use with chronic kidney disease. Finally, hypomagnesemia is another reported complication and is thought to be resulting from GI loss of magnesium. This study will critically review literature on the effect of PPIs on the kidney.

Dementia, cognitive impairment and proton pump inhibitor therapy: A systematic review

BACKGROUND AND AIM

Proton pump inhibitors (PPIs) are among the most widely used medications worldwide. Dementia is an increasingly common cause of disability in older populations. Recent studies have suggested an increased risk of cognitive impairment and dementia diagnosis among people who consume PPIs. This systematic review explores dementia, cognitive impairment, and the use of PPIs.

METHODS

Systematic searches were conducted in the databases of MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), PSYCinfo, Scopus, Web of Science, and ClinicalTrials.gov for articles published from inception to June 30, 2016. Primary outcomes of interest were the use of PPIs and diagnosis of dementia or acute cognitive impairment. Studies conducted on people aged less than 18 years old were excluded. All study designs were eligible for inclusion. Two reviewers independently assessed study quality and extracted data from included studies.

RESULTS

The systematic search strategy and screening process yielded 11 studies for inclusion in the systematic review. Four studies explored PPI use and dementia, and seven studies explored PPI use and acute cognitive impairment. Three of the four studies exploring dementia identified a positive association with PPI use. A positive association was also observed in the majority of studies exploring acute cognitive impairment.

CONCLUSIONS

Based on the current published literature, this systematic review has identified that the reported association between PPI use and dementia is limited by methodological issues and conflicting results. Further longitudinal studies with robust bias limitation are required to explore the use of PPIs and dementia or acute cognitive impairment, and to ascertain the existence of any causal relationships.

Proton pump inhibitors alter the composition of the gut microbiota

OBJECTIVE

Proton pump inhibitors (PPIs) are drugs used to suppress gastric acid production and treat GI disorders such as peptic ulcers and gastro-oesophageal reflux. They have been considered low risk, have been widely adopted, and are often over-prescribed. Recent studies have identified an increased risk of enteric and other infections with their use. Small studies have identified possible associations between PPI use and GI microbiota, but this has yet to be carried out on a large population-based cohort.

DESIGN

We investigated the association between PPI usage and the gut microbiome using 16S ribosomal RNA amplification from faecal samples of 1827 healthy twins, replicating results within unpublished data from an interventional study.

RESULTS

We identified a significantly lower abundance in gut commensals and lower microbial diversity in PPI users, with an associated significant increase in the abundance of oral and upper GI tract commensals. In particular, significant increases were observed in Streptococcaceae. These associations were replicated in an independent interventional study and in a paired analysis between 70 monozygotic twin pairs who were discordant for PPI use. We propose that the observed changes result from the removal of the low pH barrier between upper GI tract bacteria and the lower gut.

CONCLUSIONS

Our findings describe a significant impact of PPIs on the gut microbiome and should caution over-use of PPIs, and warrant further investigation into the mechanisms and their clinical consequences.

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.

Therapeutic effects of mosapride citrate and lansoprazole for prevention of aspiration pneumonia in patients receiving gastrostomy feeding

BACKGROUND

Aspiration pneumonia is an emerging problem in patients receiving gastrostomy feeding. This study is designed to clarify the therapeutic effects of mosapride citrate and lansoprazole for prevention of aspiration pneumonia in patients receiving gastrostomy feeding.

METHODS

The study subjects were 119 patients with dysphasia who required gastrostomy feeding. They were randomly assigned to the control (without medication), lansoprazole (15 mg, 1/day), and mosapride (5 mg, 3/day) groups. The number of days with fever (≥37.8 °C), vomiting, and antibiotics administration, as well as the occurrence of pneumonia were investigated during the 6-month observation period.

RESULTS

The incidence of pneumonia during the observation period was significantly lower in the mosapride group as compared to the control (7/38 vs. 16/40, p = 0.038) and lansoprazole (vs. 20/41, p = 0.005) groups. The mosapride group also showed a significant decrease in days with fever and antibiotics administration as compared to the other groups. Multivariate analysis revealed that the presence of hiatal hernia was a significant risk factor and administration of mosapride was a significant preventive factor for pneumonia.

CONCLUSION

Mosapride has a preventive effect on occurrence of pneumonia in patients receiving gastrostomy feeding.

Safety review in 10,008 users of lansoprazole in daily practice

Purpose-Soon after the introduction of the proton pump inhibitor, lansoprazole, a 4-year observational follow-up study was started to evaluate the safety of this drug in naturally-occurring groups of patients in The Netherlands. Results of this study were compared with clinical trial data and the limited published data from observational studies.Methods- prospective, observational study in which patients with a new episode of lansoprazole use were followed during the medication period for a maximum of 2 years. All (adverse) events during use were documented by the prescriber, irrespective of possible association with lansoprazole therapy.Results- total of 805 general practitioners (GPs) and 266 specialists provided a total of 10,008 lansoprazole users with a broad range of diagnoses. Of all patients, 17.4% reported one or more adverse events. The profile and frequency of reported adverse events was consistent with results from clinical trials and other observational studies. The most frequently reported adverse events were diarrhoea, headache, nausea, skin disorders, dizziness and generalized abdominal pain/cramps. There was no new evidence of rare adverse events. Furthermore, no lansoprazole-related unlabelled adverse events of clinical significance were recorded.Conclusions- Although the patterns of use of lansoprazole in daily practice deviated to some extent from the diagnoses in the information leaflet, lansoprazole was found to have a highly acceptable safety profile in this large naturally-occurring group of users. Reporting rates were higher soon after introduction of lansoprazole before falling to a lower stable level. Copyright (c) 2000 John Wiley & Sons, Ltd.

Long-term acid inhibition: benefits and harms

Proton pump inhibitors (PPIs) are the drugs of choice in the therapy of acid-related disorders. PPIs are as a class remarkably safe. Serious adverse events such as acute interstitial nephritis are extremely rare. Some reports in recent years have placed some concern on the long-term use of PPIs. Long-term therapy with PPIs can cause hypochlorhydria, hypergastrinemia and has interactions on hepatic cytochrome P450 enzymes which might increase the risk of infectious complications, nutritional deficiencies and drug-drug interactions. The vast majority of data came from retrospective case-control or cohort studies which are prone to confounders. At the moment we cannot conclude that long-term PPI use causes anemia, osteoporosis and bone fractures, increases the risk for pulmonary or enteric infections, has an effect on GUT mucosa, polyp or tumor formation, or that PPI use increases the risk of cardiovascular events in patients on PPIs and clopidogrel. We need prospective randomized trials to be able to definitely answer the questions raised in epidemiologic studies. Maintenance therapy with PPIs should be started only if strict indications for that therapy are fulfilled.

Effect of CYP2C19 genetic polymorphism on pharmacokinetics and pharmacodynamics of a new proton pump inhibitor, ilaprazole

It is well known that the CYP2C19 genetic polymorphism influences the pharmacokinetics and pharmacodynamics of proton pump inhibitors (PPIs), but no report has addressed the effects on ilaprazole, a newly developed PPI. To investigate the effects of the CYP2C19 genetic polymorphism on the disposition and pharmacodynamics of ilaprazole, multiple doses of once-daily 10 mg ilaprazole were repeatedly administered for 7 days to 27 healthy Korean participants, comprising 9 homozygous CYP2C19 extensive metabolizers (homo EMs), 10 heterozygous EMs (hetero EMs), and 8 homozygous poor metabolizers (PMs). The plasma concentration and pharmacodynamic response were measured in the last dose interval. Each genotype group was matched for gender and thus was composed of 4 male and 4 female participants when the analysis was conducted. The pharmacokinetic parameters estimated from the plasma concentrations of ilaprazole and its metabolite ilaprazole sulfone, the serum gastrin level, and the 24-hour intragastric pH were compared among the CYP2C19 genotype groups. No statistically significant differences in the maximum plasma concentration at steady state(C(ss,max)) and the area under the concentration-time curve from zero to 24 hours (AUC(τ)) of ilaprazole and ilaprazole sulfone were observed among the homo EM, hetero EM, and PM CYP2C19 genotypes. In addition, the mean 24-hour intragastric pH, the percentage of time at pH >4, and the AUC(τ) of serum gastrin showed no significant differences among the CYP2C19 genotype groups. The data suggests that the pharmacokinetics and pharmacodynamics of ilaprazole are not significantly influenced by the CYP2C19 genetic polymorphism in healthy participants.

Attenuation of stress-induced gastric lesions by lansoprazole, PD-136450 and ranitidine in rats

Combining restraint with cold temperature (4°C) consistently induces gastric ulceration in rats after 3.5 h. The cold restraint-stress (CRS) method provides a suitable model for acute ulcer investigations. This study compares the antiulcer activities of lansoprazole (a proton pump inhibitor), PD-136450 (CCK(2)/gastrin receptor antagonist) and ranitidine (histamine H(2) receptor antagonist) on CRS-induced gastric ulcers in rats. The results have shown that lansoprazole, which is a potent anti-secretory agent, provides complete protection in this model of ulcer formation. The use of indomethacin pretreatment to inhibit the prostaglandin (PG) synthesis and N(G)-nitro L-arginine methyl ester (L-NAME) pretreatment to inhibit nitric oxide synthase did not alter the lansoprazole-induced inhibition of ulcer index obtained in the untreated Wistar rats indicating that these two systems were not involved in the activation of lansoprazole. PD-136450, an effective anti-secretory agent against gastrin- but not dimaprit-induced stimulation, evoked a dose-dependent inhibition of CRS-induced gastric ulcers. The results show that both PG and nitric oxide pathways can influence the inhibitory effect of PD-136450 against CRS-induced gastric ulcer. The antiulcer activities of both lansoprazole and PD-136450 were compared to that of ranitidine. The results showed that ranitidine was more potent than lansoprazole and PD-136450 in inhibiting CRS-induced gastric ulcers and its effect was shown to be influenced by PG as well as nitric oxide synthase. The results of this study have demonstrated that although lansoprazole, PD-136450 and ranitidine were protective against CRS-induced gastric ulcers, the antiulcer activities of PD-136450 and ranitidine involved both PG and nitric oxide pathways, while lansoprazole acted independently of these two systems during CRS.

Proton pump inhibitors and rebound acid hypersecretion

Rebound acid hypersecretion is defined as an increase in gastric acid secretion above pre-treatment levels after cessation of antisecretory therapy. Proton pump inhibitors (PPIs) have been proved to be more effective than histamine-2 receptor antagonists in suppressing intragastric acidity and have therefore become the main choice for management of acid-related complaints. Recent studies have shown that PPI therapy-elicited rebound acid hypersecretion could in turn induce acid-related symptoms. This makes it difficult for patients to cease PPI therapy. Hypergastrinemia is an important mechanism that leads to rebound acid hypersecretion. To reduce the occurrence of rebound acid hypersecretion, efforts should be made to restrict indications for using PPIs.

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.

Current pharmacological management of gastro-esophageal reflux in children: an evidence-based systematic review

Gastro-esophageal reflux (GER) is a common phenomenon, characterized by the regurgitation of the gastric contents into the esophagus. Gastro-esophageal reflux disease (GERD) is the term applied when GER is associated with sequelae or faltering growth. The main aims of treatment are to alleviate symptoms, promote normal growth, and prevent complications. Medical treatments for children include (i) altering the viscosity of the feeds with alginates; (ii) altering the gastric pH with antacids, histamine H(2) receptor antagonists, and proton pump inhibitors; and (iii) altering the motility of the gut with prokinetics, such as metoclopramide and domperidone. Our aim was to systematically review the evidence base for the medical treatment of gastro-oesophageal reflux in children. We searched PubMed, AdisOnline, MEDLINE, and EMBASE, and then manually searched reviews from the past 5 years using the key words 'gastro-esophageal' (or 'gastroesophageal'), 'reflux', 'esophagitis', and 'child$' (or 'infant') and 'drug$' or 'therapy'. Articles included were in English and had an abstract. We used the levels of evidence adopted by the Centre for Evidence-Based Medicine in Oxford to assess the studies for all reported outcomes that were meaningful to clinicians making decisions about treatment. This included the impact of clinical symptoms, pH study profile, and esophageal appearance at endoscopy. Five hundred and eight articles were reviewed, of which 56 papers were original, relevant clinical trials. These were assessed further. Many of the studies considered had significant methodological flaws, although based on available evidence the following statements can be made. For infant GERD, ranitidine and omeprazole and probably lansoprazole are safe and effective medications, which promote symptomatic relief, and endoscopic and histological healing of esophagitis. Gaviscon(R) Infant sachets are safe and can improve symptoms of reflux. There is less evidence to support the use of domperidone or metoclopramide. More evidence is needed before other anti-reflux medications can be recommended. For older children, acid suppression is the mainstay of treatment. The largest evidence base supports the early use of H(2) receptor antagonists or proton pump inhibitors.

Effect of MDR1 C3435T polymorphism on lansoprazole in healthy Japanese subjects

BACKGROUND AND AIMS

The effect of multidrug resistance transporter gene 1 (MDR1) on the bioavailability and kinetics of several substrates has not yet been fully elucidated. We evaluated the influence of MDR1 C3435T polymorphism on the pharmacokinetics and pharmacodynamics of lansoprazole in Japanese subjects.

METHODS

Fifteen healthy volunteers with the rapid extensive metabolizer genotype of CYP2C19 were classified into three MDR1 C3435T genotype groups: C/C (n = 5), C/T (n = 5), and T/T (n = 5). Lansoprazole 30 mg was administered orally for 15 days. The intragastric pH and plasma lansoprazole levels were determined on days 1 and 15.

RESULTS

On day 1, the mean C(max) of lansoprazole in the T/T group was significantly higher than that in the C/C or C/T groups (T/T 1,248, C/C 618, C/T 607 ng/ml; P = 0.038). On day 15, similar MDR1 genotype-dependent differences were observed in the C(max) of lansoprazole, although smaller than the differences observed on day 1. In contrast, the intragastric pH attained after lansoprazole administration did not differ among MDR1 genotype groups on either day 1 or day 15.

CONCLUSION

Although the sample size was small, our study demonstrated that the MDR1 C3435T polymorphism influenced the pharmacokinetics, but not the pharmacodynamics (i.e., intragastric pH), of lansoprazole in rapid metabolizers of CYP2C19.

CYP2C19 pharmacogenomics associated with therapy of Helicobacter pylori infection and gastro-esophageal reflux diseases with a proton pump inhibitor

Proton pump inhibitors (PPIs), such as omeprazole, lansoprazole and rabeprazole, are metabolized by CYP2C19 in the liver. There are genetic differences in the activity of this enzyme. Genotypes of CYP2C19 are classified into three groups, rapid metabolizer (RM: *1/*1), intermediate metabolizer (IM: *1/*X) and poor metabolizer (PM: *X/*X) (*1 and 'X' represent the wild-type and mutant allele, respectively). The pharmacokinetics and pharmacodynamics of PPIs differ among three different CYP2C19 genotype groups. Plasma PPI levels and intragastric pHs during PPI treatment in the RM group are lowest, those in the IM group come next, and those in the PM group are highest of the three groups. These CYP2C19 genotypic differences in pharmacokinetics and pharmacodynamics of PPIs influence the healing and eradication rates for the gastro-esophageal reflux disease and Helicobacter pylori infection by PPI-based regimens. Recently, the CYP2C19 genotype-based tailored therapy for H. pylori infection has been found to be effective. CYP2C19 pharmacogenetics should be taken into consideration for the personalization of a PPI-based therapy.

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.

Pharmacokinetics of proton pump inhibitors in children

The use of proton pump inhibitors (PPIs) has become widespread in children and infants for the management of paediatric acid-related disease. Pharmacokinetic profiles of only omeprazole and lansoprazole have been well characterised in children over 2 years of age with acid-related diseases. Few data have been recently published regarding the pharmacokinetics of pantoprazole in children, and none are available for rabeprazole or esomeprazole. The metabolism of PPI enantiomers has never been studied in the paediatric population. A one-compartment model best describes the pharmacokinetic behaviour of omeprazole, lansoprazole and pantoprazole in children, with important interindividual variability for each pharmacokinetic parameter. Like adults, PPIs are rapidly absorbed in children following oral administration; the mean time to reach maximum plasma concentration varies from 1 to 3 hours. Since these agents are acid labile, their oral formulations consist of capsules containing enteric-coated granules. No liquid formulation is available for any of the PPIs. Thus, for those patients unable to swallow capsules, extemporaneous liquid preparations for omeprazole and lansoprazole have been reported; however, neither the absolute nor the relative bioavailabilities of these oral formulations have been studied in children. Intravenous formulations are available for omeprazole (in Europe), lansoprazole and pantoprazole. PPIs are rapidly metabolised in children, with short elimination half-lives of around 1 hour, similar to that reported for adults. All PPIs are extensively metabolised by the liver, primarily by cytochrome P450 (CYP) isoforms CYP2C19 and CYP3A4, to inactive metabolites, with little unchanged drug excreted in the urine. Similar to that seen in adults, the absolute bioavailability of omeprazole increases with repeated dosing in children; this phenomenon is thought to be due to a combination of decreased first-pass elimination and reduced systemic clearance. The apparent clearance (CL/F) of omeprazole, lansoprazole and pantoprazole appears to be faster for children than for adults. A higher metabolic capacity in children as well as differences in the extent of PPI bioavailability are most likely responsible for this finding. This may partly account for the need in children for variable and sometimes considerably greater doses of PPIs, on a per kilogram basis, than for adults to achieve similar plasma concentrations. Furthermore, no studies have been able to demonstrate a statistically significant correlation between age and pharmacokinetic parameters among children. Despite the small number of very young infants studied, there is some evidence for reduced PPI metabolism in newborns. The limited paediatric data regarding the impact of CYP2C19 genetic polymorphism on PPI metabolism are similar to those reported for adults, with poor metabolisers having 6- to 10-fold higher area under the concentration-time curve values compared with extensive metabolisers. Finally, because a pharmacokinetic/pharmacodynamic relationship exists for PPIs, the significant interindividual variability in their disposition may partly explain the wide range of therapeutic doses used in children. Further studies are needed to better define the pharmacokinetics of PPIs in children <2 years of age.

Long-term prevention of erosive or ulcerative gastro-oesophageal reflux disease relapse with rabeprazole 10 or 20 mg vs. placebo: results of a 5-year study in the United States

BACKGROUND

Erosive gastro-oesophageal reflux disease (GERD) is a chronic condition requiring long-term maintenance treatment. However, few trials of proton pump inhibitors in maintaining healing of erosive or ulcerative GERD are conducted for longer than 1 year.

AIM

To compare the efficacy and safety of 10- and 20-mg rabeprazole with placebo in the 5-year maintenance of healing in patients previously diagnosed with erosive/ulcerative GERD healed in an acute efficacy trial.

METHODS

Patients (N = 497) were randomized to receive once-daily doses of 10- or 20-mg rabeprazole or placebo. The primary efficacy measure was endoscopically documented absence of oesophageal erosions or ulcerations.

RESULTS

After 5 years, relapse rates in both rabeprazole groups were significantly lower than with placebo (rabeprazole 20 mg, 11%; 10 mg, 23%; placebo, 63%; P < 0.001 for rabeprazole vs. placebo; P = 0.005 for rabeprazole 20 mg vs. 10 mg). Both rabeprazole doses were significantly superior to placebo in preventing relapse of heartburn frequency and improving patient quality of life. Analyses of adverse events, biopsy findings and laboratory values showed no evidence of clinically significant effects.

CONCLUSIONS

Five-year maintenance therapy with rabeprazole is effective in preventing relapse of erosive or ulcerative GERD and is well tolerated.

Influence of CYP2C19 pharmacogenetic polymorphism on proton pump inhibitor-based therapies

Proton pump inhibitors (PPIs), such as omeprazole, lansoprazole, rabeprazole, esomeprazole, and pantoprazole, are mainly metabolized by CYP2C19 in the liver. There are genetically determined differences in the activity of this enzyme. The genotypes of CYP2C19 are classified into the three groups, rapid extensive metabolizer (RM), intermediate metabolizer (IM), and poor metabolizer (PM). The pharmacokinetics and pharmacodynamics of PPIs depend on CYP2C19 genotype status. Plasma PPI levels and intragastric pHs during PPI treatment in the RM group are lowest, those in the IM group come next, and those in the PM group are highest of the three groups. These CYP2C19 genotype-dependent differences in pharmacokinetics and pharmacodynamics of PPIs influence the cure rates for the gastro-esophageal reflux disease and H. pylori infection by PPI-based therapies. For the better PPI-based treatment, doses and dosing schemes of PPIs should be optimized based on CYP2C19 genotype status.

The choice of proton pump inhibitor: does it matter?

Proton pump inhibitors are used at different dosages for the treatment of acid-related gastrointestinal disorders, such as gastro-oesophaeal reflux and peptic ulcer disease. Comparisons of four different proton pump inhibitors: lansoprazole, omeprazole, pantoprazole, and rabeprazole show that they all have similar potency and efficacy. Rabeprazole, however, displays a slightly more rapid onset of acid inhibition than the others; the clinical advantage of this seems limited. The S-isomer of omeprazole, esomeprazole, exhibits a somewhat higher potency than the other proton pump inhibitors. Reports supporting a clinical advantage of this property are not convincing. To conclude, all inhibitors seem comparable as regards inhibition of gastric acid secretion.

Pharmacogenomics of proton pump inhibitors

Proton pump inhibitors (PPIs), such as omeprazole, lansoprazole, rabeprazole, esomeprazole, and pantoprazole, are metabolized by cytochrome P450 isoenzyme 2C19 (CYP2C19) in the liver. There are genetic differences that affect the activity of this enzyme. The genotypes of CYP2C19 are classified into three groups: homozygous extensive metabolizer (homEM), heterozygous extensive metabolizer (hetEM), and poor metabolizer (PM). The pharmacokinetics and pharmacodynamics of PPIs differ among the different CYP2C19 genotype groups. Plasma PPI and intragastric pH levels during PPI treatment are the lowest in the homEM group and the highest in the PM group. These CYP2C19 genotype-dependent differences in pharmacokinetics and pharmacodynamics of PPIs are reflected in the cure rates for gastroesophageal reflux disease and Helicobacter pylori infection with PPI-based therapies. The CYP2C19 genotyping test is a useful tool for deciding on the optimal treatment regimen using a PPI, including a dual (PPI plus antibiotic) or a triple (PPI plus two antibiotics) therapy.

Treatment of acid-related diseases in the elderly with emphasis on the use of proton pump inhibitors

Proton pump inhibitors (PPIs) have revolutionised the treatment of acid-related disorders, and they have also made it possible to define the spectrum of acid inhibition required for optimal treatment in each disorder. Five PPIs are now available: the older drugs, omeprazole, lansoprazole and pantoprazole, and the two newest, rabeprazole and esomeprazole. These agents have predominantly been developed in the younger adult population, and data for the elderly population are limited. Subtle differences have emerged between the old and the new PPIs in their pharmacokinetic, pharmacodynamic and efficacy profiles. The degree of clinical relevance of these differences in the adult population is in question. However, according to this review, based on the available data for the elderly and by inference from the adult population, the differences are highly relevant in the elderly population. Studies of the pharmacokinetics of older PPIs demonstrated considerable variation in drug clearance that was reflected in a wide range of efficacy related to acid suppression with standard dosages. The newer PPIs offer several advantages over older agents, particularly in terms of rapid, profound and consistent acid inhibition. Consistent acid inhibition is particularly important in the elderly since clinical response is often difficult to judge in this patient group. An individual's cytochrome P450 (CYP) 2C19 genotype predicts the degree of acid suppression and consequently the clinical efficacy of the PPIs. The older PPIs are predominantly metabolised by CYP2C19, with this being of more importance for omeprazole and lansoprazole than pantoprazole. The hepatic metabolism of rabeprazole is predominantly by nonenzymatic reactions and minimally by CYP-mediated reactions, which therefore confers an advantage over older PPIs in that genetic polymorphisms for CYP2C19 do not significantly influence rabeprazole clearance, clinical efficacy or potential for drug interactions. The metabolism of esomeprazole involves CYP2C19 but to a lesser extent than its predecessor omeprazole. Furthermore, esomeprazole has a more rapid onset of action and less variation in clearance rates than omeprazole. Drug clearance decreases with age independently of CYP2C19 status, exaggerating some of the differences between the PPIs and increasing the risk of drug interactions.

Lansoprazole: in the management of gastroesophageal reflux disease in children

Lansoprazole, a proton pump inhibitor, inactivates the H(+)/K(+)-ATPase pump in parietal cells, thereby suppressing basal and stimulated gastric acid secretion and increasing intragastric pH. After 8-12 weeks' treatment with lansoprazole, all children (n = 27) with esophagitis at baseline were healed (confirmed by endoscopy) and 76% of 62 evaluable children experienced improvements in overall gastroesophageal reflux disease (GERD) symptoms. In this noncomparative trial, 66 children (aged 1-11 years) with GERD with or without esophagitis received oral lansoprazole 15 or 30 mg once daily dependent on their weight. The drug is generally well tolerated in children with GERD. In the largest study, the most common treatment-related adverse events occurring during therapy were constipation and headache.

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.

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.

Lansoprazole-associated microscopic colitis: a case series

Lansoprazole is a potent proton pump inhibitor that has been well tolerated with minimal serious adverse events. One of the most commonly reported side effects is diarrhea in 3-8% of study patients. During 1997, approximately 850 veterans at our institution had their proton pump inhibitor converted from omeprazole to lansoprazole because of a formulary change. A number of patients subsequently developed chronic watery diarrhea. While evaluating six of these patients, we discovered microscopic colitis that resolved with discontinuation of lansoprazole. The diarrhea was described as three to 10 loose, nonbloody bowel movements per day with some abdominal cramping. Colonoscopy in five patients and flexible sigmoidoscopy in one patient revealed normal colonic mucosa, but random biopsies all supported microscopic colitis (five cases of lymphocytic colitis and one case of collagenous colitis). Complete symptom resolution occurred in all patients within 4 to 10 days of discontinuing lansoprazole. In all patients, follow-up biopsies demonstrated normalization of the colonic histology. This is the first published case series of patients with microscopic colitis that correlated clinically and histologically with the initiation and discontinuation of lansoprazole.

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.

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

Esomeprazole, the S-isomer of omeprazole, is the first proton pump inhibitor to be developed as a single optical isomer. It provides better acid control than current racemic proton pump inhibitors and has a favourable pharmacokinetic profile relative to omeprazole. In large well designed 8-week trials in patients with erosive oesophagitis, esomeprazole recipients achieved significantly higher rates of endoscopically confirmed healed oesophagitis than those receiving omeprazole or lansoprazole. Esomeprazole was effective across all baseline grades of oesophagitis; notably, relative to lansoprazole, as the baseline severity of disease increased, the difference in rates of healed oesophagitis also increased in favour of esomeprazole. In two trials, 94% of patients receiving esomeprazole 40mg once daily achieved healed oesophagitis versus 84 to 87% of omeprazole recipients (20mg once daily). In a study in >5000 patients, respective healed oesophagitis rates with once-daily esomeprazole 40mg or lansoprazole 30mg were 92.6 and 88.8%. Resolution of heartburn was also significantly better with esomeprazole than with these racemic proton pump inhibitors. Long-term (up to 12 months) therapy with esomeprazole effectively maintained healed oesophagitis in these patients. Esomeprazole 20 or 40mg once daily for 4 weeks proved effective in patients with symptomatic gastro-oesophageal reflux disease (GORD) without oesophagitis. Eradicating Helicobacter pylori infection is considered pivotal to successfully managing duodenal ulcer disease. Ten days' triple therapy (esomeprazole 40mg once daily, plus twice-daily amoxicillin 1g and clarithromycin 500mg) eradicated H. pylori in 77 to 78% of patients (intention-to-treat) with endoscopically confirmed duodenal ulcer disease. Esomeprazole is generally well tolerated, both as monotherapy and in combination with antimicrobial agents. The tolerability profile is similar to that of other proton pump inhibitors. Few patients discontinued therapy because of treatment-emergent adverse events (<3% of patients) and very few (<1%) drug-related serious adverse events were reported.

CONCLUSIONS

Esomeprazole is an effective and 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 effectively healed oesophagitis and resolved symptoms in patients with endoscopically confirmed erosive oesophagitis. Notably, in large (n >1900 patients) double-blind trials, esomeprazole provided significantly better efficacy than omeprazole or lansoprazole in terms of both healing rates and resolution of symptoms. Long-term therapy with esomeprazole effectively maintained healed oesophagitis in these patients. Esomeprazole was also effective in patients with symptomatic GORD. Thus, esomeprazole has emerged as an effective option for first-line therapy in the management of acid-related disorders.

Lansoprazole: an update of its place in the management of acid-related disorders

Lansoprazole is an inhibitor of gastric acid secretion and also exhibits antibacterial activity against Helicobacter pylori in vitro. Current therapy for peptic ulcer disease focuses on the eradication of H. pylori infection with maintenance therapy indicated in those patients who are not cured of H. pylori and those with ulcers resistant to healing. Lansoprazole 30 mg combined with amoxicillin 1g, clarithromycin 250 or 500mg, or metronidazole 400 mg twice daily was associated with eradication rates ranging from 71 to 94%, and ulcer healing rates were generally >80% in well designed studies. In addition, it was as effective as omeprazole- or rabeprazole-based regimens which included these antimicrobial agents. Maintenance therapy with lansoprazole 30 mg/day was significantly more effective than either placebo or ranitidine in preventing ulcer relapse. Importantly, preliminary data suggest that lansoprazole-based eradication therapy is effective in children and the elderly. In the short-term treatment of patients with gastro-oesophageal reflux disease (GORD), lansoprazole 15, 30 or 60 mg/day was significantly more effective than placebo, ranitidine 300 mg/day or cisapride 40 mg/day and similar in efficacy to pantoprazole 40 mg/day in terms of healing of oesophagitis. Lansoprazole 30 mg/day, omeprazole 20 mg/day and pantoprazole 40 mg/day all provided similar symptom relief in these patients. In patients with healed oesophagitis. 12-month maintenance therapy with lansoprazole 15 or 30 mg/day prevented recurrence and was similar to or more effective than omeprazole 10 or 20 mg/day. Available data in patients with NSAID-related disorders or acid-related dyspepsia suggest that lansoprazole is effective in these patients in terms of the prevention of NSAID-related gastrointestinal complications, ulcer healing and symptom relief. Meta-analytic data and postmarketing surveillance in >30,000 patients indicate that lansoprazole is well tolerated both as monotherapy and in combination with antimicrobial agents. After lansoprazole monotherapy commonly reported adverse events included dose-dependent diarrhoea, nausea/vomiting, headache and abdominal pain. After short-term treatment in patients with peptic ulcer, GORD, dyspepsia and gastritis the incidence of adverse events associated with lansoprazole was generally < or = 5%. Similar adverse events were seen in long-term trials, although the incidence was generally higher (< or = 10%). When lansoprazole was administered in combination with amoxicillin, clarithromycin or metronidazole adverse events included diarrhoea, headache and taste disturbance. In conclusion, lansoprazole-based triple therapy is an effective treatment option for the eradication of H. pylori infection in patients with peptic ulcer disease. Preliminary data suggest it may have an important role in the management of this infection in children and the elderly. In the short-term management of GORD, lansoprazole monotherapy offers a more effective alternative to histamine H2-receptor antagonists and initial data indicate that it is an effective short-term treatment option in children and adolescents. In adults lansoprazole maintenance therapy is also an established treatment option for the long-term management of this chronic disease. Lansoprazole has a role in the treatment and prevention of NSAID-related ulcers and the treatment of acid-related dyspepsia; however, further studies are needed to confirm its place in these indications. Lansoprazole has emerged as a useful and well tolerated treatment option in the management of acid-related disorders.

Mono, dual and triple moxifloxacin-based therapies for Helicobacter pylori eradication

BACKGROUND

Moxifloxacin is a broad spectrum fluoroquinolone with single daily administration, currently used, above all, for respiratory tract infections.

AIM

To compare the efficacy of different 1-week moxifloxacin-based Helicobacter pylori eradication regimens.

METHODS

One hundred and twenty H. pylori-positive subjects were randomized to receive moxifloxacin (400 mg/day), moxifloxacin (400 mg/day) and lansoprazole (30 mg/day) or moxifloxacin (400 mg/day), lansoprazole (30 mg/day) and clarithromycin (500 mg b.d.). H. pylori status was reassessed 6 weeks after the end of therapy, and both intention-to-treat and per protocol analyses were performed.

RESULTS

One hundred and nineteen of the 120 patients completed the study. H. pylori eradication was achieved in 22.5% of patients treated with moxifloxacin, in 33.3% of subjects treated with moxifloxacin and lansoprazole and in 90% of patients treated with moxifloxacin, clarithromycin and lansoprazole.

CONCLUSIONS

Mono and dual moxifloxacin-based therapies are not acceptable for H. pylori eradication; conversely, moxifloxacin-based triple therapy may be considered as a new, effective, first-line therapy option.

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.

Clinical pharmacology and safety profile of esomeprazole, the first enantiomerically pure proton pump inhibitor

Awareness of important differences in the pharmacological profile of individual optical isomers of chiral drugs led to the development of esomeprazole, the S-isomer of omeprazole, a new pharmacological entity designed to improve the clinical outcome of available proton pump inhibitors in the management of acid-related disorders. The superior acid control achieved by esomeprazole is mainly due to an advantageous metabolism compared with racemate omeprazole, leading to improved bioavailability and to enhanced delivery of the drug to the gastric proton pump.

Lansoprazole in children: pharmacokinetics and efficacy in reflux oesophagitis

BACKGROUND

Data on the proton pump inhibitor lansoprazole in paediatric patients are limited.

AIM

To investigate the pharmacokinetics, optimal dosage and efficacy of lansoprazole in paediatric patients.

METHODS

A 24-h gastric pH recording and a pharmacokinetic study were performed after 7 days of lansoprazole, 17 mg/m2, in 23 patients with reflux oesophagitis (median age, 3.5 years). Response was defined as pH > 3 for > 65% of the recording. The dosage was doubled in non-responders. Patients with no response on day 14 were excluded. Responders underwent endoscopy after 4 weeks on the response-inducing dosage; abnormal findings led to a repeat endoscopy after four additional weeks.

RESULTS

Nine patients responded to 17 mg/m2 and six to 30.3 mg/m2. On day 7, time with pH > 3 was significantly correlated with the area under the plasma concentration-time curve (P=0.003). The area under the plasma concentration-time curve was significantly greater in the nine responders to 17 mg/m2 than in the 14 other patients. Pharmacokinetic parameters were similar in responders and non-responders to the higher dose. After 4 weeks, oesophagitis was healed in 80% of responders. Adverse events occurred in three patients and required treatment discontinuation in one.

CONCLUSIONS

Lansoprazole is effective and safe in children. The optimal starting dosage is 30 mg/m2 or 1.4 mg/kg.

Pharmacological and pharmacodynamic essentials of H(2)-receptor antagonists and proton pump inhibitors for the practising physician

The suppression of gastric acid secretion with anti-secretory agents has been the mainstay of medical treatment for patients with acid-related disorders. Although the majority of Helicobacter pylori -related peptic ulcers can be healed with antibiotics, ulcer healing and symptom control can be significantly improved when antibiotics are given with anti-secretory agents, especially with a proton pump inhibitor. There is a dynamic relationship between the suppression of intragastric acidity and the healing of peptic ulcer and erosive oesophagitis and control of acid-related symptoms. The suppression of gastric acid secretion achieved with H(2)-receptor antagonists has, however, proved to be suboptimal for effectively controlling acid-related disorders, especially for healing erosive oesophagitis and for the relief of reflux symptoms. H(2)-receptor antagonists are also not effective in inhibiting meal-stimulated acid secretion, which is required for managing patients with erosive oesophagitis. Furthermore, the rapid development of tolerance to H(2)-receptor antagonists and the rebound acid hypersecretion after the withdrawal of an H(2)-receptor antagonist further limit their clinical use. Although low-dose H(2)-receptor antagonists are currently available as over-the-counter medications for self-controlling acid-related symptoms, their pharmacology and pharmacodynamics have not been well studied, especially in the self-medicating population. Proton pump inhibitors have been proved to be very effective for suppressing intragastric acidity to all known stimuli, although variations exist in the rapidity of onset of action and the potency of acid inhibition after oral administration at the approved therapeutic doses, which may have important clinical implications for the treatment of gastro-oesophageal reflux disease and perhaps for eradicating H. pylori infection when a proton pump inhibitor is given with antibiotics. Once-daily dosing in the morning is more effective than dosing in the evening for all proton pump inhibitors with respect to the suppression of intragastric acidity and daytime gastric acid secretion in particular, which may result from a better bio-availability being achieved with the morning dose. When higher doses are needed, these drugs must be given twice daily to achieve the optimal suppression of 24 hour intragastric acidity. Preliminary results have shown that esomeprazole, the optical isomer of omeprazole, given at 40 mg, is significantly more effective than omeprazole 40 mg, lansoprazole 30 mg or pantoprazole 40 mg for suppressing gastric acid secretion. However, more studies in different patient populations are needed to compare esomeprazole with the existing proton pump inhibitors with regard to their efficacy, cost-effectiveness and long-term safety for the management of acid-related disorders.

Switching between intravenous and oral pantoprazole

Proton pump inhibitors (PPIs) are the most effective antisecretory drugs available for controlling gastric acid acidity and volume. They are the drugs of choice in the treatment of moderate-to-severe gastroesophageal reflux disease, hypersecretory disorders, and peptic ulcers. Currently in the United States, they are only available in an oral formulation. However, pantoprazole will soon be available in an intravenous formulation and will extend the power of PPIs to inpatient hospital settings. Intravenous pantoprazole has been shown to be effective and safe in clinical trials. Intravenous pantoprazole is indicated for the treatment of patients who require PPI therapy but who are unable to take oral medication. Intravenous pantoprazole has been shown to maintain acid suppression in patients switched from oral PPIs, so no change in dosage is required when switching from one formulation to the other. Potential hospital-based uses for intravenous PPI therapy include perioperative use as prophylaxis for acid aspiration syndrome during induction of anesthesia, prophylaxis for stress-related mucosal disease, and management of gastrointestinal bleeding from stress or acid peptic disease.

Rabeprazole for the prevention of pathologic and symptomatic relapse of erosive or ulcerative gastroesophageal reflux disease. Rebeprazole Study Group

OBJECTIVE

We evaluated the effectiveness and safety profile of 10 and 20 mg of rabeprazole, a new proton pump inhibitor, once daily versus placebo in preventing endoscopic and symptomatic relapse for up to 1 yr among patients with healed erosive or ulcerative gastroesophageal reflux disease (GERD).

METHODS

The 52-wk trial used a multicenter, randomized, double-blind, parallel-group design in which 209 men and women were assigned to 10 or 20 mg of rabeprazole once daily in the morning or placebo.

RESULTS

Both rabeprazole doses were significantly superior to placebo in preventing endoscopic relapse (p < 0.001), and 20 mg was significantly more effective than 10 mg (p < 0.04). Both doses were also significantly superior to placebo in reducing the frequency and severity of heartburn relapse (p < 0.001). When adjusted for differences in exposure to study medication, no significant differences were found in the incidence of adverse events. No clinically significant changes were found regarding clinical laboratory parameters, vital signs, electrocardiograms, ophthalmological evaluations, body weight, serum gastrin, and enterochromaffin-like cell histology.

CONCLUSIONS

Once-daily therapy with 10 or 20 mg of rabeprazole effectively prevents pathological and symptomatic GERD relapse. The 20-mg dose is significantly more effective than the 10-mg dose in preventing endoscopic recurrence. Treatment was well tolerated, and no clinically significant safety findings emerged. Our findings support rabeprazole's efficacy in preventing GERD recurrence with excellent tolerability and a short-term favorable safety profile.

Proton pump inhibitors in the treatment of gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease (GERD) is the most common peptic acid disease in the western world and is the commonest indication for acid suppression therapy. Major advances have been made over the past 30 years in the understanding of lower oesophageal sphincter function and the mechanism of acid secretion. Developments in surgical and pharmacological therapy have paralleled these advances. Pharmacotherapy for GERD has evolved from antacids to H2-receptor antagonists (H2RAs) to prokinetics to proton pump inhibitors (PPIs). The H2RAs, while modestly effective in symptom relief and healing of GERD, are limited by pharmacological tolerance. The prokinetics (metoclopramide and cisapride) are limited by low efficacy, pharmacological tolerance and toxicity. The PPIs have emerged as the most effective therapy for symptom relief, healing and long-term maintenance. They have also proved to be remarkably safe and cost-effective in long-term therapy. This review evaluates the pharmacology, efficacy, tolerability, safety and cost-effectiveness of the four currently available PPIs, lansoprazole, omeprazole, pantoprazole and rabeprazole, in the treatment of GERD.

Review article: comparison of the pharmacokinetics, acid suppression and efficacy of proton pump inhibitors

Proton pump inhibitors have dramatically influenced the management of acid-peptic disorders in recent years. They all have a broadly similar mechanism of action and are extensively metabolized in the liver via cytochromes P450 2C19 and 3A4. There is some variation in their potential for drug interactions due to differences in enzyme inhibition. Relatively few serious adverse effects have been reported for the proton pump inhibitors. Comparative studies of acid suppression suggest that lansoprazole and pantoprazole have a potency similar to that of omeprazole on a mg for mg basis; however, rabeprazole may have a greater potency than omeprazole. Lansoprazole and rabeprazole display a more rapid onset of maximal acid suppression than the other proton pump inhibitors. Comparative studies using proton pump inhibitors for the treatment of reflux oesophagitis, duodenal ulcer healing and Helicobacter pylori eradication show little overall difference in outcome between the proton pump inhibitors when used in their standard doses. Lansoprazole and rabeprazole provide earlier and better symptom relief than the other proton pump inhibitors in some studies of peptic ulcer treatment. The few studies of gastric ulcer treatment suggest that there is an advantage in using the proton pump inhibitors that have a higher standard daily dose.

Acute gastrointestinal bleeding in the intensive care unit. The gastroenterologist's perspective

Although SRES-associated hemorrhage previously constituted a significant cause of bleeding in the ICU, improvements in ICU management and the institution of prophylactic measures in high-risk patients have significantly reduced SRES-associated hemorrhage since the 1980s. Antacids, H2-receptor antagonists, and sucralfate have been shown to be effective in preventing clinically significant bleeding resulting from SRES, particularly when the intragastric pH is maintained at greater than 4. A selective approach should be adopted in SRES prophylaxis: Patients on mechanical ventilation, with coagulopathy, or with two of the other known risk factors should receive prophylaxis. Although the drug of choice depends to some extent on local preferences, an H2-receptor antagonist by continuous intravenous infusion may represent the best option. No pharmacologic therapy is of proven value once hemorrhage begins, but the current interventional techniques are effective in controlling hemorrhage. Gastrointestinal bleeding from NOMV has become less common with improvements in the hemodynamic monitoring of critically ill patients, but this disease must always be considered when lower gastrointestinal bleeding occurs in the context of relative hypoperfusion. For SRES and NOMV, treatment of the underlying disease or diseases is the optimal route to prevention.

The proton-pump inhibitors: similarities and differences

OBJECTIVE

This paper examines the clinical pharmacology of the proton-pump inhibitors (PPIs) and briefly reviews some comparative studies of these agents.

BACKGROUND

PPIs have emerged as the treatment of choice for acid-related diseases, including gastroesophageal reflux disease (GERD) and peptic ulcer disease. Although these drugs-omeprazole, lansoprazole, pantoprazole, and rabeprazole-share a common structure (all are substituted benzimidazoles) and mode of action (inhibition of H+,K+-adenosine triphosphatase [ATPase]), each differs somewhat in its clinical pharmacology.

RESULTS

In comparative clinical trials found in MEDLINE, PPIs administered once daily produced endoscopic evidence of healing in >90% of patients with duodenal ulcer after 4 weeks of treatment, in >90% of those with gastric ulcer after 6 weeks of treatment, and in >90% of those with ulcerative or erosive GERD after 8 weeks of treatment. Maintenance therapy with daily doses of a PPI has been shown to be an effective means of preventing GERD relapse. PPIs also inhibit the growth of Helicobacter pylori, now recognized as an important factor in peptic ulcer disease, and, when administered in combination with antibiotics, provide the best treatment for eradication of the bacterium. Rabeprazole has a more rapid onset of H+,K+-ATPase inhibition than the other PPIs and, compared with omeprazole, a greater effect on intragastric pH after the first dose. Omeprazole and lansoprazole have a greater potential for drug-drug interactions than do pantoprazole and rabeprazole.

CONCLUSION

Although the individual PPIs have similar efficacy in many cases, differences between them should be considered when choosing a treatment regimen.