Omeprazole

Inhibition of Erythromycin and Erythromycin-Induced Resistance among Staphylococcus aureus Clinical Isolates

The increasing incidence of erythromycin and erythromycin-induced resistance to clindamycin among Staphylococcus aureus (S. aureus) is a serious problem. Patients infected with inducible resistance phenotypes may fail to respond to clindamycin. This study aimed to identify the prevalence of erythromycin and erythromycin-induced resistance and assess for potential inhibitors. A total of 99 isolates were purified from various clinical sources. Phenotypic detection of macrolide-lincosamide-streptogramin B (MLSB)-resistance phenotypes was performed by D-test. MLSB-resistance genes were identified using PCR. Different compounds were tested for their effects on erythromycin and inducible clindamycin resistance by broth microdilution and checkerboard microdilution methods. The obtained data were evaluated using docking analysis. Ninety-one isolates were S. aureus. The prevalence of constitutive MLSB, inducible MLSB, and macrolide-streptogramin (MS) phenotypes was 39.6%, 14.3%, and 2.2%, respectively. Genes including ermC, ermA, ermB, msrA, msrB, lnuA, and mphC were found in 82.6%, 5.8%, 7.7%, 3.8%, 3.8%, 13.5%, and 3.8% of isolates, respectively. Erythromycin resistance was significantly reduced by doxorubicin, neomycin, and omeprazole. Quinine, ketoprofen, and fosfomycin combated and reversed erythromycin/clindamycin-induced resistance. This study highlighted the significance of managing antibiotic resistance and overcoming clindamycin treatment failure. Doxorubicin, neomycin, omeprazole, quinine, ketoprofen, and fosfomycin could be potential inhibitors of erythromycin and inducible clindamycin resistance.

Application of Physiologically Based Pharmacokinetic Modeling in Preclinical Studies: A Feasible Strategy to Practice the Principles of 3Rs

Pharmacokinetic characterization plays a vital role in drug discovery and development. Although involving numerous laboratory animals with error-prone, labor-intensive, and time-consuming procedures, pharmacokinetic profiling is still irreplaceable in preclinical studies. With physiologically based pharmacokinetic (PBPK) modeling, the in vivo profiles of drug absorption, distribution, metabolism, and excretion can be predicted. To evaluate the application of such an approach in preclinical investigations, the plasma pharmacokinetic profiles of seven commonly used probe substrates of microsomal enzymes, including phenacetin, tolbutamide, omeprazole, metoprolol, chlorzoxazone, nifedipine, and baicalein, were predicted in rats using bottom-up PBPK models built with in vitro data alone. The prediction's reliability was assessed by comparison with in vivo pharmacokinetic data reported in the literature. The overall predicted accuracy of PBPK models was good with most fold errors within 2, and the coefficient of determination (R2) between the predicted concentration data and the observed ones was more than 0.8. Moreover, most of the observation dots were within the prediction span of the sensitivity analysis. We conclude that PBPK modeling with acceptable accuracy may be incorporated into preclinical studies to refine in vivo investigations, and PBPK modeling is a feasible strategy to practice the principles of 3Rs.

Use of Proton Pump Inhibitors and Risk of Pancreatic Cancer: A Nationwide Case-Control Study Based on the French National Health Data System (SNDS)

BACKGROUND

Only a few studies investigated the association between proton pump inhibitor (PPI) use and pancreatic cancer, with inconsistent results. Moreover, these studies had a number of methodologic limitations. Our objective was to assess this association in a nationwide case-control study.

METHODS

We used the French National Health Data System (SNDS), covering 99% of the French population since 2006. Incident cases of pancreatic cancer, identified between 2014 and 2018, were matched with up to four controls on year of birth, sex, frequency of hospitalization within 8 years prior to index date, and department of residence. Associations between PPIs and pancreatic cancer were estimated using conditional logistic regression models adjusted for sociodemographic characteristics, risk factors of pancreatic cancer (including diabetes mellitus, tobacco-related diseases, and morbid obesity), and other comorbidities.

RESULTS

A total of 23,321 cases of pancreatic cancer (mean age, 69.8 years; 51.7% males) and 75,937 matched controls were included. Overall, 77.8% of cases and 75.5% of controls were PPI ever users. Ever (vs. never) PPI use was associated with an increased risk of pancreatic cancer [adjusted OR (aOR) = 1.05, 95% confidence interval (CI), 1.01-1.09]. A dose-response relationship was observed [1-30 cumulative defined daily dose (cDDD): aOR = 0.92, 95% CI, 0.87-0.97; 31-180 cDDD: aOR = 1.05, 95% CI, 1.00-1.11; 181-1,080 cDDD: aOR = 1.18, 95% CI, 1.12-1.24; >1,080 cDDD: aOR = 1.17, 95% CI, 1.10-1.23].

CONCLUSIONS

On the basis of these findings, a slight increase in the risk of pancreatic cancer associated with high cumulative doses of PPIs cannot be excluded.

IMPACT

Given the overuse of PPIs, efforts should be continued to limit treatments to appropriate indications and durations.

Omeprazole inhibits α-glucosidase activity and the formation of nonenzymatic glycation products: Activity and mechanism

In this study, the inhibitory effect and mechanism of omeprazole on α-glucosidase and nonenzymatic glycation were investigated in vitro by using multi-spectroscopic methods and molecular docking. Enzyme kinetic results showed that omeprazole inhibited α-glucosidase in a reversible and noncompetitive manner (IC₅₀= 0.595 ± 0.003 mM). The results from fluorescence quenching and thermomechanical analyses signified that omeprazole reduced the fluorescence intensity of α-glucosidase by forming an omeprazole-α-glucosidase complex primarily driven by hydrogen bonds. Molecular docking further confirmed that hydrogen bonds and hydrophobic forces were the major driving forces for omeprazole binding to α-glucosidase. The nonenzymatic glycation assays revealed that omeprazole had a moderate inhibition against the formation of fructosamine, dicarbonyl compounds, and advanced glycation end products (AGEs). This study provides a new inhibitor of both α-glucosidase and nonenzymatic glycation and provides a practicable candidate for treating diabetes and its complications.

A prospective randomized controlled trial of omeprazole for preventing esophageal stricture in grade 2b and 3a corrosive esophageal injuries

OBJECTIVES

Esophageal stricture is a significant complication of grade 2b and 3a esophageal injuries and causes much patient suffering. Preventing strictures would be beneficial to patients but there are currently no proven effective drugs. This study aimed to evaluate the effect of omeprazole for preventing esophageal stricture in adults with grade 2b and 3a corrosive esophageal injuries.

METHODS

This study was an open single-center prospective randomized controlled trial that took place from April 2018 to January 2020. Patients were randomized to standard treatment or 80 mg/day intravenously × 3 days followed by 40 mg/day orally for 4 weeks. They were endoscoped at baseline and 4 weeks post discharge. Strictures were confirmed radiologically.

RESULTS

20 patients were enrolled: 15 with grade 2b and five with grade 3a injuries. Standard care and omeprazole groups numbered 10 each. At 1 month, seven and two patients developed strictures in the standard and omeprazole groups, respectively, p = 0.024, for a risk reduction of 71.4%.

CONCLUSIONS

Omeprazole reduced the risk of short-term developing esophageal strictures following grade 2b and 3a corrosive esophageal injuries. Larger studies are needed to reconfirm this finding. Thai Clinical Trials Registry (TCTR) number TCTR20190504001.

Project IDentif.AI: Harnessing Artificial Intelligence to Rapidly Optimize Combination Therapy Development for Infectious Disease Intervention

In 2019/2020, the emergence of coronavirus disease 2019 (COVID‐19) resulted in rapid increases in infection rates as well as patient mortality. Treatment options addressing COVID‐19 included drug repurposing, investigational therapies such as remdesivir, and vaccine development. Combination therapy based on drug repurposing is among the most widely pursued of these efforts. Multi‐drug regimens are traditionally designed by selecting drugs based on their mechanism of action. This is followed by dose‐finding to achieve drug synergy. This approach is widely‐used for drug development and repurposing. Realizing synergistic combinations, however, is a substantially different outcome compared to globally optimizing combination therapy, which realizes the best possible treatment outcome by a set of candidate therapies and doses toward a disease indication. To address this challenge, the results of Project IDentif.AI (Identifying Infectious Disease Combination Therapy with Artificial Intelligence) are reported. An AI‐based platform is used to interrogate a massive 12 drug/dose parameter space, rapidly identifying actionable combination therapies that optimally inhibit A549 lung cell infection by vesicular stomatitis virus within three days of project start. Importantly, a sevenfold difference in efficacy is observed between the top‐ranked combination being optimally and sub‐optimally dosed, demonstrating the critical importance of ideal drug and dose identification. This platform is disease indication and disease mechanism‐agnostic, and potentially applicable to the systematic N‐of‐1 and population‐wide design of highly efficacious and tolerable clinical regimens. This work also discusses key factors ranging from healthcare economics to global health policy that may serve to drive the broader deployment of this platform to address COVID‐19 and future pandemics.

IgE-mediated allergy to proton pump inhibitors with both delayed and immediate onset

Proton pump inhibitors (PPIs) are widely used for the treatment of gastrointestinal diseases. Incidence of drug hypersensitivity reactions (DHRs) to PPIs has been rising, presumably because of their increased consumption. Most DHR are IgE-mediated, with half of the reactions being anaphylactic. We describe the case of a Caucasian 50-year-old female patient referred to our allergy department after 2 episodes of anaphylaxis. The allergy work-up distinguished PPI as a cause of delayed onset (14 hours) and immediate onset (45 minutes) IgE-mediated DHR.

Current Status of Gastric Proton Pump Inhibitors in the Treatment of Acid-Peptic Disease

Proton pump inhibitors represent an important advance in the treatment of acid-peptic disease. Omeprazole, the prototype of the drug class, produces a profound and sustained degree of gastric acid suppression. Recent studies confirm earlier reports that omeprazole 20 mg/d is generally more effective than standard histamine2 receptor antagonist (H2RA) dosage regimens in treating duodenal ulcer (DU), gastric ulcer (GU), and erosive esophagitis. Omeprazole tends to accelerate DU and GU healing, especially during the first 2 weeks of treatment, and also accelerates mucosal healing in patients with all grades of esophagitis. Omeprazole is the drug of choice for treating patients with large or refractory ulcers, severe or refractory erosive esophagitis, Barrett's esophagus, and Zollinger-Ellison syndrome. Maintenance therapy with omeprazole seems to reduce ulcer recurrence and esophagitis, but optimal treatment regimens must be established. Dual therapy with omeprazole and amoxicillin shows encouraging results in eradicating Helicobacter pylori, reducing duodenal ulcer recurrence rates, and altering the natural history of peptic ulcer disease. Further studies are required to determine the efficacy of omeprazole in preventing nonsteroidal anti-inflammatory drug-induced ulcers and stress-related mucosal bleeding, and in treating upper gastrointestinal bleeding. Omeprazole is well-tolerated in the majority of patients receiving either short-term or long-term treatment. The type and frequency of adverse effects are similar to those reported with the H2RAs. There is no evidence to support genotoxicity or hypergastrinemia-induced enterochromaffin-like cell carcinoid of the stomach in patients receiving omeprazole treatment for more than 5 years. Omeprazole interacts selectively with hepatic P-450 and may potentially interact with phenytoin, warfarin, or diazepam. Pharmacoeconomic studies suggest that treatment with omeprazole provides a significant cost-savings over the H2RAs in patients with moderate to severe erosive esophagitis and possibly in patients with DU. Lansoprazole, a newly developed proton pump inhibitor, seems to offer no clear advantage over omeprazole.

Effects of Thymus hirtus sp. algeriensis Boiss. et Reut. (Lamiaceae) essential oil on healing gastric ulcers according to sex

BACKGROUND

Thymus algeriensis Boiss. et Reut. (Lamiaceae), popularly known as "mougecha" or "mazoukcha" is prolific in Mediterranean regions, mostly in North Africa, and is used in folk medicine to treat of stomach diseases.

METHODS

In this study, animals were induced with gastric ulcers using HCl/ethanol (0.3 M HCl/60% ethanol) and treated orally with essential oil of Thymus algeriensis (EOTa) in various doses ranging from 54 mg/kg body weight to 180 mg/kg body weight.

RESULT

The dose found to be effective was 180 mg/kg body weight, since this dose brought about a maximum reduction in lesion index in female rats. In gastric tissues, levels of total glutathiones (GSH, GST and GPx) and thiobarbituric acid reactive substances (TBARS) were evaluated. The activities of the antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD) were measured. Histopathological changes were observed using a cross section of gastric tissue. Chemical analysis revealed the presence of 13 components accounting for 77.7% of the essential oil from dried leaves. Oral administration of EOTa (54, 117 and 180 ml/kg) inhibited HCl/ethanol-induced ulcers. Lesion index was significantly reduced in ulcer induced animals treated with EOTa (HCl/ethanol + EOTa) compared to those ulcerated with HCl/ethanol but with no treatment given. Females showed a greater resistance to ulcers and gastric lesions occurred less often than in males. GSH, pH, enzymic antioxidants, and adherent mucus content were all significantly increased.

CONCLUSION

From the data presented in this study, it can be concluded that male rats are more sensitive to gastric ulcers induced by HCl/ethanol than females.

A review of stress-related mucosal disease

OBJECTIVE

To review and summarize the human and veterinary literature regarding stress-related mucosal disease (SRMD) pathogenesis, patient risk factors, and therapeutic options for prophylaxis and treatment.

ETIOLOGY

SRMD is a common sequela of critical illness in human patients. Development of SRMD results from splanchnic hypoperfusion, reperfusion injury, and exposure of the gastric mucosa to acid, pepsin, and bile acids following breakdown of the gastric mucosal defense system. Human patients with the highest risk of stress ulceration include those with respiratory failure necessitating mechanical ventilation greater than 48 h or coagulopathy. Currently, little is known about the incidence and pathophysiology of SRMD in critically ill veterinary patients.

DIAGNOSIS

A presumptive diagnosis can be made in high-risk patient populations following detection of occult or gross blood in nasogastric tube aspirates, hematemesis, or melena. Definitive diagnosis is achieved via esophagogastroduodenoscopy. Lesions are localized to the acid-producing portions of the stomach, the fundus, and body.

THERAPY

Therapy is aimed at optimization of tissue perfusion and oxygenation. Pharmacologic interventions are instituted to increase intraluminal pH and augment natural gastric defenses. Histamine(2)-receptor antagonists, proton pump inhibitors, and sucralfate are the mainstays of therapy. In people, clinically significant bleeding may necessitate additional interventions (eg, packed red blood cell transfusions, endoscopic, or surgical hemostasis).

PROGNOSIS

Mortality is increased in people with clinically significant bleeding compared to those patients who do not bleed. Institution of prophylaxis is recommended in high-risk patients. However, no consensus exists regarding initiation of prophylaxis, preference of frontline drug class, or indication for discontinuation of therapy. The prognosis of veterinary patients with SRMD remains unknown at this time.

The potential inhibitory effect of revaprazan, an acid pump antagonist, on anticoagulation with warfarin

Revaprazan is the first acid pump antagonist with a function similar to that of proton pump inhibitors (PPIs). It has a dual action, active suppression of gastric acid secretion and gastric mucosa protection. While PPIs are known to enhance the prolongation of prothrombin time by warfarin, no research has been done on the drug interaction between revaprazan and warfarin. This study was conducted in order to verify the potential drug interaction between revaprazan and warfarin. Omeprazole, a representative PPI, was used as the control for revaprazan. We searched for patients who were given either revaprazan or omeprazole along with warfarin using the medical record database of Seoul National University Hospital between July 2007 and June 2010. Among the 15 patients who took revaprazan and warfarin together, 73.3% (11/15) showed more than 30% reduction of anticoagulation effect by warfarin after revaprazan was added. The revaprazan group showed a significant shortening of prothrombin time during revaprazan administration compared to pre- and post-revaprazan medication (P < 0.05) while the omeprazole group did not show such difference. Revaprazan seems to have cumulative dose-dependent anti-warfarin or anti-coagulation effect, as judged from the fact that the longer medication with revaprazan showed correlation with the shortening of prothrombin time (R = -0.632, P < 0.05). This study shows a possible interaction between revaprazan and warfarin and suggests that revaprazan can cause shortening of prothrombin time. Therefore, when revaprazan is prescribed to patients on warfarin therapy, prothrombin time should be frequently monitored.

Intravenous proton pump inhibitors for peptic ulcer bleeding: Clinical benefits and limits

Peptic ulcer bleeding is a common disease and recurrent bleeding is an independent risk factor of mortality. Infusion with proton pump inhibitors (PPIs) prevents recurrent bleeding after successful endoscopic therapy. A gastric acidic environment of less than pH 5.4 alters coagulation function and activates pepsin to disaggregate platelet plugs. Gastric acid is secreted by H⁺, K⁺-ATPase, naming the proton pump. This update review focuses on the mechanism and the role of PPIs in the clinical management of patients with peptic ulcer bleeding. An intravenous omeprazole bolus followed by high-dose continuous infusion for 72 h after successful endoscopic therapy can prevent the recurrent bleeding. In the Asian, however, the infusion dosage can possibly be diminished whilst preserving favorable control of the intragastric pH and thereby still decreasing rates of recurrent bleeding. Irrespective of the infusion dosage of PPIs, rates of recurrent bleeding remain high in patients with co-morbidities. Because recurrent peptic ulcer bleeding may be prolonged in those with co-morbidities, a low-dose infusion of IV PPIs for up to 7-day may result in better control of recurrent bleeding of peptic ulcers. Due to the inter-patient variability in CYP2C19 genotypes, the infusion form of new generation PPIs, such as esomeprazole, should be promising for the prevention of recurrent bleeding. This article offers a comprehensive review of clinical practice, highlighting the indication, the optimal dosage, the duration, and the potential limitation of PPIs infusion for peptic ulcer bleeding.

Precision improvement for omeprazole determination through stability evaluation

A new spectrofluorimetric method for the determination of omeprazole (OMP) based on its degradation reaction catalyzed by ultraviolet (UV) light is proposed. OMP in aqueous solution is very unstable, which renders a serious difficulty for controlling its quality. It does not show native fluorescence, but when exposed to UV radiation, it generates a highly fluorescent degradation product with adequate stability for indirect OMP quantification. Under the studied optimal experimental conditions (pH, temperature, exposure time to UV radiation), a specific rate constant of 2.851 min⁻¹--described by zero-order kinetic--was obtained for the degradation reaction. Using λ(exc) 293 nm and λ(em) 317 nm, a linear relationship was obtained (r² 0.9998) in the concentration range of 0.1 to 1.3 µg mL⁻¹, with a detection limit of 1.07 10⁻³ µg mL⁻¹ (S/N = 3). The methodology developed was successfully applied to OMP quality control in pure drugs and tablet dosage forms without previous treatment, with good tolerance to common excipient, and a high level of concordance between the nominal and experimental values. This work constitutes an important contribution to knowledge of the degradation mechanism of OMP. It has been shown to be appropriate for OMP quality control, to have an adequate sampling rate, low cost instrument, and to be a less polluting procedure.

Proton pump inhibitors in the management of GERD

INTRODUCTION

Management of gastroesophageal reflux disease (GERD) is based on the concept that gastric contents, principally acid and pepsin, are responsible for symptoms of reflux and esophageal injury. Pharmacologic treatment is based on the principle that controlling intragastric pH will affect esophageal healing and subsequently symptom relief.

RESULTS AND DISCUSSION

Control of pH can be accomplished with antisecretory agents, principally proton pump inhibitors (PPIs). The majority of patients respond to a single daily dose of a PPI; however, some will require higher doses, and a small percentage are "refractory" to twice daily dosing of these drugs. The success of these agents, and in fact the reasons for "failure," is elucidated by understanding the mechanism of action of PPIs and the effect of dose timing and meals on their efficacy.

CONCLUSION

Awareness of new concerns regarding potential side effects of PPIs when used long-term require careful thought as GERD is a chronic disease with most needing some form of medical treatment over time. This article reviews the pharmacologic properties of PPIs and the impact on the treatment of GERD.

Additional bedtime H2-receptor antagonist for the control of nocturnal gastric acid breakthrough

BACKGROUND

Nocturnal gastric acid breakthrough (NAB) is defined as intragastric pH<4 for more than one continuous hour overnight. Adding H(2)-receptor antagonists (H2RAs) at bedtime to high-dose proton pump inhibitors is likely to enhance nocturnal gastric pH control and decrease nocturnal gastric acid breakthrough.

OBJECTIVES

To assess the effectiveness of additional bedtime H2-receptor antagonists in suppressing nocturnal gastric acid breakthrough and the incidence of adverse effects.

SEARCH STRATEGY

We identified eligible trials by searching The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2008), MEDLINE (1966-August 2008), EMBASE (1980-August 2008) and CINAHL (1982-August 2008). We re-ran the search on CENTRAL (The Cochrane Library Issue 4, 2008), and in MEDLINE, EMBASE and CINAHL in June 2004, July 2005, August 2006 and August 2008.

SELECTION CRITERIA

All randomized controlled trials evaluating H2-receptor antagonists for the control of nocturnal gastric acid breakthrough were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two reviewers have independently selected the trials to be included in the review according to the pre-stated eligibility criteria. Disagreements were resolved by a third reviewer. If the data could not be pooled for meta-analysis, a narrative description was provided.

MAIN RESULTS

8 small randomized controlled trials were included for meta-analysis. The results show that additional bedtime H2RAs can decrease the prevalence rate of nocturnal gastric acid breakthrough. The results of the analyses for secondary outcomes show that additional bedtime H2RAs can decrease the percentage of time during which pH is less than 4.0 inside the stomach and promote median intragastric pH.

AUTHORS' CONCLUSIONS

We can conclude no implications for practice at this stage. Appropriately designed large-scale randomized controlled trials with long-term follow-up are needed to determine the effects of additional bedtime H2RAs in suppressing nocturnal gastric acid breakthrough.

A novel placement method of the Bravo wireless pH monitoring capsule for measuring intragastric pH

PURPOSE

The delivery system of the Bravo capsule was designed for placement on the esophagus. We evaluated the feasibility of our novel placement method of the Bravo capsule using a clip to monitor intragastric pH and to compare the accuracy of the Bravo wireless system to the traditionally used Slimline catheter-Mark III Digitrapper pH monitoring system.

METHODS

The Bravo capsule was placed by clip or conventional delivery system using suction on the gastric wall in 20 fasted subjects. A separate group of ten healthy volunteers underwent simultaneous intragastric pH monitoring for comparison of the two systems with meals.

RESULTS

Early dislodgment rate of the capsules was lower when placed using clipping (20%) than using conventional delivery system (70%) within 48 h after placement. We observed prominent movement of one catheter in the stomach during the study. Post-test calibration drifts of the catheters at pH 7.01 were significantly greater than those of the Bravo capsules (P = 0.02).

CONCLUSION

Our novel clipping method of the Bravo pH capsule placement provided accurate monitoring of intragastric pH with merits of tolerability, acid stability, and fixing position.

Pantoprazole on-demand effectively treats symptoms in patients with gastro-oesophageal reflux disease

OBJECTIVE

The efficacy of pantoprazole as on-demand therapy for the long-term management of patients with mild gastro-oesophageal reflux disease (GORD) has been demonstrated in clinical studies. In this study, the efficacy of pantoprazole 20mg and esomeprazole 20mg as on-demand therapy for relief of symptoms of mild GORD was compared.

METHODS

Patients with reflux oesophagitis grade A or B (Los Angeles classification) or endoscopy-negative reflux disease (enGORD) were treated with pantoprazole 20mg once daily for 28 days during the acute phase (AP, n = 236). Patients without heartburn during the final 3 days of the AP entered the long-term phase (LTP, n = 199) and were randomised to either pantoprazole 20mg or esomeprazole 20mg as on-demand treatment for 6 months. Antacids were provided as rescue medication during this phase. The mean intensities of the symptoms of heartburn, acid eructation and pain on swallowing, both separately and as a combined symptom score, together with the mean duration of these symptoms during on-demand treatment, were compared between the two treatment groups. The number of tablets taken was also compared.

RESULTS

After 4 weeks of treatment with pantoprazole, 87.3% of patients had relief from heartburn, 74.1% from epigastric pain and 80.8% from acid eructation, according to the investigator assessment. A total of 236 patients were eligible for the on-demand phase. Based on patient diary data, on-demand treatment with pantoprazole resulted in significantly lower mean intensity of heartburn compared with that in the esomeprazole group (1.12 for pantoprazole and 1.32 for esomeprazole, respectively [p = 0.012], in the intention-to-treat [ITT] population). The mean symptom intensities of acid eructation and pain on swallowing, together with the duration of these symptoms, were comparable in the two treatment groups. The combined symptom score of the three symptoms heartburn, acid eructation and pain on swallowing was numerically lower in the pantoprazole group compared with the esomeprazole group (1.72 vs 1.99, respectively, in the ITT population). Tablet intake was comparable in both groups. Relief of symptoms in Helicobacter pylori-positive and -negative patients was also similar in both treatment groups. Both treatments were well tolerated with a good safety profile.

CONCLUSION

On-demand therapy with either pantoprazole 20mg or esomeprazole 20mg is a comparably effective treatment strategy for the long-term treatment of non-erosive and mild GORD. However, the mean intensity of heartburn was significantly lower with pantoprazole treatment.

Future prospects for proton pump inhibitors

Future prospects for proton pump inhibitors depend on their efficacy and safety relative to H2-receptor antagonists, the therapeutic standard for acid peptic disorders. As safety concerns diminish, efficacy considerations become more important as these may pertain to cost effectiveness. Comparative, controlled trials show that omeprazole and lansoprazole are somewhat more effective than H2-blockers in healing duodenal and gastric ulcers, providing faster relief of symptoms. Relapse after cessation of therapy is similar between the two classes. The proton pump inhibitors are substantially more effective in healing lesions and relieving symptoms in patients with reflux oesophagitis, and are particularly effective in cases that have failed to heal after 12 weeks of treatment with H2-blockers. Relapse rates of oesophagitis are significantly less with prolonged treatment with omeprazole than ranitidine. A proton pump inhibitor combined with amoxicillin is less effective than triple therapy with antibiotics and bismuth in eradicating Helicobacter pylori infections, but is more convenient and associated with fewer side-effects. Efficacy might be improved by more optimal dosing regimens. Prospects for reversible proton pump inhibitors depend on the balance between their theoretical advantages and their acid inhibition profile which, at present, closely resembles that of H2-blockers.

Medical management of gastroesophageal reflux disease

Gastroesophageal reflux disease is a common worldwide disorder. Most patients have typical symptoms of heartburn, regurgitation and exacerbation of symptoms with large meal volumes, fatty meals, recumbency or bending forward. Patients who show typical symptoms for under 10 years may be treated empirically with lifestyle and dietary modifications plus acid-suppressing medications. The recent decrease in cost, established safety and wide availability of proton pump inhibitors make them the best choice for monotherapy. Other medical therapies include antacids, H(2) receptor antagonists and prokinetic agents. Patients who have alarm symptoms or long-standing symptoms should have an esophagoscopy to evaluate for complications of reflux. Patients who do not respond to therapy should have a test to confirm the diagnosis of gastroesophageal reflux disease.

Absolute bioavailability and metabolism of omeprazole in relation to CYP2C19 genotypes following single intravenous and oral administrations

OBJECTIVE

The aim of this study was to evaluate the absolute bioavailability and the metabolism of omeprazole following single intravenous and oral administrations to healthy subjects in relation to CYP2C19 genotypes.

METHODS

Twenty subjects, of whom 6 were homozygous extensive metabolizers (hmEMs), 8 were heterozygous EMs (htEMs) and 6 were poor metabolizers (PMs) for CYP2C19, were enrolled in this study. Each subject received either a single omeprazole 20 mg intravenous dose (IV) or 40 mg oral dose (PO) in a randomized fashion during 2 different phases.

RESULTS

Mean omeprazole AUC (0,infinity) was 1164, 3093 and 10511 ng h/mL after PO, and 1435, 2495 and 6222 ng h/mL after IV in hmEMs, htEMs and PMs, respectively. Therefore, the absolute bioavailability of omeprazole in PMs was significantly higher than that in hmEMs (p < 0.001) and htEMs (p < 0.001). Hydroxylation metabolic indexes after IV and PO were significantly lower in PMs than in hmEMs (p < 0.001) and htEMs (p < 0.001), and was correlated with the absolute bioavailability (p < 0.0001 for both IV and PO). Sulfoxidation metabolic index after IV was significantly different between the CYP2C19 genotypes, whereas no difference was found after a single oral dose.

CONCLUSION

This study indicates that the absolute bioavailability of omeprazole differs among the three different CYP2C19 genotypes after a single dose of omeprazole orally or intravenously. Hydroxylation metabolic index of omeprazole may be mainly attributable to the genotype of CYP2C19. As for the sulfoxidation metabolic index after a single oral dose, intestinal CYP3A may be contributed to omeprazole metabolism.

Additional bedtime H2-receptor antagonist for the control of nocturnal gastric acid breakthrough: a Cochrane systematic review

OBJECTIVES

To assess the effectiveness and safety of additional bedtime H(2)-receptor antagonists (H(2)RAs) in suppressing nocturnal gastric acid breakthrough (NAB) via a systematic review.

METHODS

Eligible trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 2, 2004), MEDLINE (January 1966-June 2004), EMBASE (January 1980-June 2004) and CINAHL (January 1982-June 2004). Additional hand-searching was conducted on the proceedings of correlated conferences, eight important Chinese journals and references of all included trials. All randomized controlled trials evaluating H(2)RAs for the control of NAB were eligible for inclusion. The systematic review was conducted using methods recommended by The Cochrane Collaboration.

RESULTS

Only two randomized crossover studies, comprising 32 participants, met the inclusion criteria. Because the design, dosage and duration of the treatments were different between the studies, it was not possible to conduct meta-analysis. There were no consistent conclusions found between the two included studies in evaluating H(2)RAs for the control of NAB.

CONCLUSIONS

No implications for practice at this stage can be concluded. Appropriately designed large-scale randomized controlled trials with long-term follow up are needed to determine the effects of additional bedtime H(2)RAs in suppressing NAB.

Gastric carcinoids: a temporal increase with proton pump introduction

BACKGROUND

Recent reports have indicated a rising incidence of gastric carcinoids. This study aimed to evaluate the incidence pattern of gastric carcinoids in two large population-based cancer registries.

METHODS

The Florida Cancer Data System (FCDS), Florida's statewide cancer registry, and the Surveillance, Epidemiology, and End Results (SEER) program were used. The study population was defined as all cases of gastric carcinoid identified in either database from January 1981 to December 2000. Descriptive statistics and age-adjusted incidence rates were calculated.

RESULTS

There were 326 (FCDS) and 594 (SEER) cases of invasive gastric carcinoid during the 20-year study period. The mean age of the patients was 65 years (range, 21-96 years), and the male:female ratio was 1:1. The age-adjusted incidence rate in FCDS increased from 0.04 (per 100,000 age-adjusted to the 2000 U.S. standard population) to 0.18 in the year 2000. The estimated annual percentage change in incidence was 8.17 in FCDS and 9.17 in SEER (p < 0.05). A decrease in gastric cancer was noted during this same period (from 8.64 to 11.14 cases per 100,000 in FCDS and from 11.14 to 8.06 cases per 100,000 in SEER).

CONCLUSIONS

This study documented a statistically significant eight- or ninefold increase in the incidence of gastric carcinoids in two large databases. The temporal increase in incidence correlates with the introduction and widespread use of proton pump inhibitors since the late 1980s. Other explanations include improved detection with wider application of upper endoscopy. Further epidemiologic studies are warranted.

Review article: the long-term use of proton-pump inhibitors

More than 15 years after the launch of omeprazole in 1988, proton-pump inhibitors remain central to the management of acid-suppression disorders and are unchallenged with regard to their efficacy and popularity among doctors and patients. They are considered safe despite early concerns about the possibility of an association with cancer and gastric atrophy; current concerns about long-term proton-pump inhibitor therapy are centred mainly on a possible association with fundic gland polyps and between Helicobacter pylori and gastric atrophic changes. Long-term proton-pump inhibitor usage accounts for the majority of the total proton-pump inhibitor usage. Long-term usage is difficult to define and most patients take proton-pump inhibitors non-continuously. Data indicate that a substantial proportion of long-term users do not have a clear indication for their therapy and there is thus room for reduction or rationalization of treatment. Overall, on-demand therapy is more cost-effective than continuous therapy and should be considered wherever possible.

Clinical trends in ulcer diagnosis in a population with high prevalence of Helicobacter pylori infection

BACKGROUND

It is unknown whether the incidence of peptic ulcer changes in areas with a high prevalence of Helicobacter pylori infection.

AIM

To determine trends in peptic ulcer complications in a community with a high prevalence of H. pylori infection.

METHODS

New endoscopic diagnoses of peptic ulcers and their complications from 1985 to 2000 were obtained. H. pylori infection in the adult population, the number of prescriptions for anti-secretory drugs and non-steroidal anti-inflammatory drugs were also evaluated.

RESULTS

Although the global prevalence of H. pylori infection remains high in this population (>60%), a 41.4 to 25.4% decrease in the incidence of peptic ulcers and ulcer complications was observed. This was associated with a decrease in the prevalence of H. pylori infection in people under 65 years of age, a 3.5-fold increase in the number of prescriptions of proton-pump inhibitors and an increase in the number of prescriptions of non-steroidal anti-inflammatory drugs, especially coxibs.

CONCLUSIONS

In an area with a high prevalence of H. pylori infection, the incidence of peptic ulcer and associated complications is declining rapidly. This was associated with a reduction of the prevalence of H. pylori infection in the young and a widespread use of proton-pump inhibitors. The increase in the use of non-steroidal anti-inflammatory drugs, especially coxibs, has not changed the tendency.

Additional bedtime H2-receptor antagonist for the control of nocturnal gastric acid breakthrough

BACKGROUND

Nocturnal gastric acid breakthrough(NAB) is defined as intragastric pH<4 for more than one continuous hour overnight. Adding H2-receptor antagonists (H2RAs)at bedtime to high-dose proton pump inhibitors is likely to enhance nocturnal gastric pH control and decrease nocturnal gastric acid breakthrough.

OBJECTIVES

To assess the effectiveness of additional bedtime H2-receptor antagonists in suppressing nocturnal gastric acid breakthrough and the incidence of adverse effects.

SEARCH STRATEGY

We identified eligible trials by searching The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2003), MEDLINE (1966-July 2003), EMBASE (1980-July 2003) and CINAHL (1982-July 2003). We re-ran the search on CENTRAL (The Cochrane Library Issue 2, 2004), and in MEDLINE, EMBASE and CINAHL in June 2004.

SELECTION CRITERIA

All randomized controlled trials evaluating H2-receptor antagonists for the control of nocturnal gastric acid breakthrough were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We extracted data and recorded relevant information onto specially developed forms. One reviewer extracted data and a second reviewer checked data extraction. We have also double-checked data entry into RevMan. For binary outcomes, we expressed the impact of the intervention as relative risks, together with 95% confidence intervals. For scale-based outcomes, we used means and standard deviations to summarise the values in each group, provided the scale permitted sufficient values. We had intended to analyse such outcomes for the presence of skew, but the studies included were too limited to permit this.

MAIN RESULTS

Two randomized crossover studies including 32 participants met the inclusion criteria. Because the design, dosage and duration of the treatment were different between the studies, it was not possible to conduct meta-analysis. There is no consistent conclusion between the two included studies in evaluating H2RAs for the control of NAB.

REVIEWERS' CONCLUSIONS

We can conclude no implications for practice at this stage. Appropriately designed, large-scale randomized controlled trials with long-term follow-up are needed to determine the effects of additional bedtime H2RAs in suppressing nocturnal gastric acid breakthrough.

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Managing gastroesophageal reflux disease: from pharmacology to the clinical arena

GERD is a condition affecting patients throughout the 24-hour period, although the nighttime interval may require special consideration because of the pharmacologic profile of the agents used to treat GERD, and the normal physiologic processes rendering nighttime GERD particularly damaging. GERD patients should be managed with appropriate therapy proportional to the frequency and severity of their symptoms. PPIs are the most potent inhibitors of acid secretion, and with a thorough knowledge of their pharmacologic properties, clinicians can be helped in identifying strategies that can maximize the benefits of their potency (see Table 2). PPIs offer significant benefit to persons requiring longer-term therapy because they are potent agents and offer ease of dosing and favorable drug interaction and adverse effect profiles. However, it is necessary that clinicians understand the physiology and pharmacology of acid secretion to use them appropriately. Inevitably, proper therapeutic treatment demands that variables such as pharmacokinetics, ethnicity (metabolic profile), and the normal physiology of acid secretion be considered when choosing an appropriate PPI.

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.

Proton pump activation in stimulated parietal cells is regulated by gastric acid secretory capacity: a human study

Under normal physiological conditions, gastric acid production is controlled by a negative feedback mechanism. Proton pump inhibitors, such as pantoprazole, inhibit gastric acid secretion by irreversibly binding and inactivating luminally active hydrogen potassium ATPase. Recovery of acid production after treatment with a proton pump inhibitor is driven by new pump synthesis, activation of existing cytoplasmic pumps, or reversal of proton pump inhibition. The authors measured the time course of the inhibition and recovery of acid secretion in healthy volunteers following intravenous administration of pantoprazole to determine the rate of proton pump activation under maximally stimulated conditions. Gastric acid production was measured in 27 Helicobacter pylori negative healthy volunteers (mean age = 31 +/- 7 years; 17 men, 10 women) who received single doses of intravenous pantoprazole (20, 40, 80, or 120 mg) in the presence of a continuous intravenous infusion of 1 ug/kg/h of pentagastrin. From the time profile of acid secretion, the authors described the rate of change of acid output using an irreversible pharmacodynamic response model represented by the equation dR/dt = -k x R x Cpanto + Ln2/PPR x (Ro-R) and correlated the parameter values with demographic factors and gastric acid measurements. Mean stimulated acid output secretion was 21.6 +/- 18.4 mEq/h (range: 1.6-90.5) prior to the administration of pantoprazole and remained steady for 25 hours after placebo administration. Intravenous pantoprazole inhibited acid output in a dose-response fashion, with maximal inhibition (99.9%) occurring after an 80 mg dose. Mean proton pump recovery time was 37.1 +/- 21.0 hours (range: 6.7-75), and recovery was independent of the dose of pantoprazole. There was no association noted between proton pump recovery time and gender, age, race, body weight, or pantoprazole dose. However, there was an inverse correlation between acid output during baseline stimulation and recovery of acid secretion. Mean proton pump recovery time in stimulated normal human volunteers was 37.1 +/- 21.0 hours, with a range of 6.7 to 75 hours. The authors hypothesize that there may be a normal homeostatic mechanism that maintains acid secretory capability within a normal range by altering the rate of proton pump activation dependent on the individual's parietal cell mass. Abnormalities of this process may be responsible for the development of acid peptic disease in susceptible individuals.

A review of epidemiological studies on cancer in relation to the use of anti-ulcer drugs

H2-receptor antagonists have been widely used since the late 1970s for the treatment of gastrointestinal ulcers and other benign conditions of the stomach, oesophagus and duodenum. Several case reports suggested that long-term therapy with H2-receptor antagonists, mainly cimetidine and ranitidine, might increase the risk of gastric cancer. After early case reports, at least six analytical epidemiological studies (two cohort and four case-control) were published, including a total of about 1000 cases of gastric cancer. The relative risks (RR) were systematically and substantially elevated in the first year since starting H2-receptor antagonist use, and levelled off in the following years. Some excess risk was still apparent during the first 5 years of drug use, probably due to incorrect diagnosis and treatment of pre-existing neoplastic gastric lesions, but the estimated RR was not above unity for > or = 10 years since starting drug treatment in the two studies including information on long-term use. The findings of analytical epidemiological studies are thus consistent with the absence of a causal association between H2-receptor antagonist use and gastric cancer risk. Data on oesophageal and colorectal cancer do not support a relevant relation between cimetidine use and the risk of these neoplasms. With reference to total cancer mortality, in a Danish cohort study, for males the RR was 1.9 in the first year, and 1.4 in the first 5 years; corresponding values for females were 1.7 and 1.5. In a British cohort study, the RR was 3.4 in the first year, and 1.3 in the years 2-10. The excess risk in the first year was essentially due to gastric cancer. Post-marketing surveillance data for omeprazole and other proton pump inhibitors are much scantier than for H2-receptor antagonists, particularly on long-term use.

Pharmacology for the gastrointestinal tract

A variety of drugs are used in the neonatal nursery for the management of feeding intolerance, gastroesophageal reflux, and acid-related disease. Although the pharmacokinetics of some of these drugs have been described in infants and older children, further data are needed, particularly for preterm infants. No data are available characterizing the disposition of the proton pump inhibitors, which will likely be used in infants with refractory, acid-related disease. Further data are also needed to characterize fully the pharmacodynamics, or efficacy, of many of the commonly used drugs.

Prophylaxis and treatment of gastrointestinal complications following transplantation

Most transplant recipients will experience some type of gastrointestinal (GI) complication. These effects often are caused by infectious damage induced by a variety of opportunistic organisms, but they also may be due to mechanical injury during surgery or to metabolic or organ toxicity associated with immunosuppressive regimens. Although some of these GI complications can substantially impair quality of life or even carry significant mortality risk, many of them can be prevented, and most of them can be treated medically without the need to stop immunosuppression and expose the patient to the risk of rejection. Limiting the use of steroids, giving prophylactic antiviral and antifungal agents (particularly to patients at risk) and adopting a low threshold for endoscopy are among the most important measures that can be used to avoid GI complications after transplantation.

Safety and efficacy of long term esomeprazole therapy in patients with healed erosive oesophagitis

OBJECTIVE

To evaluate the safety and tolerability of long term treatment with esomeprazole in patients with healed erosive oesophagitis, and to describe its efficacy in the maintenance of healing.

DESIGN AND SETTING

US multicentre, noncomparative, nonblind study.

PATIENTS AND PARTICIPANTS

807 patients with endoscopically confirmed healed erosive oesophagitis.

METHODS

Patients received esomeprazole 40 mg once daily for up to 12 months. Adverse events and clinical laboratory tests were assessed over the study period. Endoscopy was performed at the final visit of the antecedent healing trials and at months 6 and 12 of the current safety trial; gastric biopsies were obtained at the initial visit of the healing trials and at the end of the safety trial.

RESULTS

80.9% of patients completed 6 months of treatment; 76.6% completed 12 months of treatment. There were no serious drug-related adverse events. Diarrhoea, abdominal pain, flatulence, and headache were the only treatment-related adverse events reported by >3% of patients. Mean changes in laboratory measures were generally small and not clinically meaningful. Plasma gastrin levels increased, as expected, and reached a plateau after 3 months. No changes in gastric histological scores were noted in the majority of patients. Evaluation of gastric biopsies revealed an overall decline in chronic inflammation and atrophy. Intestinal metaplasia findings remained essentially unchanged. Life table estimates of maintenance of healing were 93.7% [95% confidence interval (CI) 92.0 to 95.5%] at 6 months and 89.4% (95% CI 87.0 to 91.7%) at 12 months.

CONCLUSIONS

Daily treatment with esomeprazole 40 mg for up to 1 year in patients with healed erosive oesophagitis was generally well tolerated and effective. No safety concerns arose.

Chronic vomiting associated with a gastric carcinoid in a cat

A geriatric domestic shorthair cat was presented for evaluation of chronic vomiting. Chronic renal failure was diagnosed on the basis of physical examination findings and results of a serum biochemical profile and urinalysis. Endoscopically obtained gastric biopsies were suggestive of a carcinoid tumor. Subsequently, an exploratory celiotomy with partial gastrectomy was performed. Histopathological and electron microscopic analysis of surgical biopsy specimens confirmed the diagnosis of a gastric carcinoid, which has not been previously reported in the cat. Following complete excision, the cat remained clinically stable and free of signs of gastrointestinal disease for 4 months before requiring treatment for progressive renal failure.

Acute interstitial nephritis due to omeprazole

Omeprazole is a proton pump inhibitor that is used commonly in the treatment of acid-peptic disorders. Although omeprazole is generally well tolerated, serious adverse effects such as renal failure have been reported. Thus far, 17 cases of acute interstitial nephritis (AIN) secondary to omeprazole have been described. Another case of AIN is described in a 36-yr-old woman presenting with nausea, vomiting, weight loss, and a rising serum creatinine concentration. Omeprazole therapy had ceased 2 wk before admission. AIN was diagnosed by renal biopsy and corticosteroid therapy was initiated. After 4 wk of therapy the serum creatinine concentration had normalized. Among the reported cases in the literature, AIN was diagnosed after an average of 2.7 months of therapy with 20-40 mg of omeprazole daily. Recurrence was universal on rechallenge. Common symptoms included fatigue, fever, anorexia, and nausea. The classic triad of fever, rash, and eosinophilia was uncommon. Typical laboratory features included hematuria, proteinuria, pyuria, eosinophilia, and anemia. Management consisted of withdrawal of omeprazole and corticosteroid therapy in some patients. All but one patient recovered normal renal function. Corticosteroid therapy was well tolerated and may have been beneficial.

Patterns of proton pump inhibitor use in clinical practice

BACKGROUND

Little is known about differences between gastroenterologists and primary care physicians in their patterns of prescribing proton pump inhibitors.

SUBJECTS AND METHODS

A survey of practicing primary care physicians from the American Board of Medical Specialties and practicing gastroenterologists from the American Gastroenterological Association was conducted by facsimile. The survey instrument consisted of 13 questions about pharmacokinetics and administration of proton pump inhibitors.

RESULTS

The overall response rate was 15% (491 of 3273), and 80% (395 of 491) of respondents were nontrainee gastroenterologists or primary care physicians. Approximately 90% (n = 355) of eligible respondents correctly identified proton pump inhibitors as inhibitors of H+,K+-adenosinetriphosphatase. Proton pump inhibitors were prescribed by 80% (n = 314) of each group for reflux esophagitis. They were prescribed by 67% (122 of 182) of gastroenterologists and 27% (58 of 213) of primary care physicians to prevent ulcers induced by nonsteroidal anti-inflammatory drugs (P <0.001). And they were prescribed by 40% (n = 73) of gastroenterologists and 16% (n = 34) of primary care physicians for uncomplicated heartburn (P <0.001). Proton pump inhibitors were prescribed before a meal by 95% (n = 173) of gastroenterologists and 33% (n = 70) of primary care physicians (P <0.001). Nearly 99% (n = 391) of respondents agreed that proton pump inhibitors were safe, but only 15% (n = 59) thought they should be available without prescription.

CONCLUSION

Our survey suggests that the use of proton pump inhibitors differs between gastroenterologists and primary care physicians. Furthermore, although most physicians believe that proton pump inhibitors are safe, few believe that they should be available without a prescription.

Effects of acid inhibition on somatostatin-producing cells in the rat gastric fundus

Somatostatin plays a role in the regulation of gastric acid secretion. Omeprazole, a potent inhibitor of gastric acid secretion, has been reported to cause either a significant decrease or increase in the formation of gastric somatostatin-producing cells. Therefore, we determined in the present study distribution patterns of somatostatin mRNA and protein in fundus mucosa of rats after long-term inhibition of gastric acid secretion. Female Sprague-Dawley rats were given 0, 20 and 100 mg/kg/day omeprazole, respectively, as gastric instillations during 2 months. Serum gastrin levels were significantly higher in the third group than in the other groups. The omeprazole-treated groups also showed an increase in the number of somatostatin-containing cells in fundus mucosa. Moreover, the intensity of somatostatin-positivity was higher in the treated groups than in the control group. We also observed an increase in the number of cells containing somatostatin mRNA in fundus mucosa of omeprazole-treated rats. These results suggest that long-term inhibition of acid secretion does not inhibit but stimulate somatostatin production in mucosa of rat gastric fundus.

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.