Effects of esomeprazole on acid output in patients with Zollinger-Ellison syndrome or idiopathic gastric acid hypersecretion

Rational design on loop regions for precisely regulating flexibility of catalytic center to mitigate overoxidation of prazole sulfides by Baeyer-Villiger monooxygenase

S-omeprazole and R-rabeprazole are important proton pump inhibitors (PPIs) used for treating peptic disorders. They can be biosynthesized from the corresponding sulfide catalyzed by Baeyer-Villiger monooxygenases (BVMOs). During the development of BVMOs for target sulfoxide preparation, stereoselectivity and overoxidation degree are important factors considered most. In the present study, LnPAMO-Mu15 designed previously and TtPAMO from Thermothelomyces thermophilus showed high (S)- and (R)-configuration stereoselectivity respectively towards thioethers. TtPAMO was found to be capable of oxidating omeprazole sulfide (OPS) and rabeprazole sulfide (RPS) into R-omeprazole and R-rabeprazole respectively. However, the overoxidation issue existed and limited the application of TtPAMO in the biosynthesis of sulfoxides. The structural mechanisms for adverse stereoselectivity between LnPAMO-Mu15 and TtPAMO towards OPS and the overoxidation of OPS by TtPAMO were revealed, based on which, TtPAMO was rationally designed focused on the flexibility of loops near catalytic sites. The variant TtPAMO-S482Y was screened out with lowest overoxidation degree towards OPS and RPS due to the decreased flexibility of catalytic center than TtPAMO. The success in this study not only proved the rationality of the overoxidation mechanism proposed in this study but also provided hints for the development of BVMOs towards thioether substrate for corresponding sulfoxide preparation.

Long-Term Proton Pump Inhibitor-Acid Suppressive Treatment Can Cause Vitamin B12 Deficiency in Zollinger-Ellison Syndrome (ZES) Patients

Whether the long-term treatment of patients with proton pump inhibitors (PPIs) with different diseases [GERD, Zollinger-Ellison syndrome (ZES), etc.] can result in vitamin B12 (VB12) deficiency is controversial. In this study, in 175 patients undergoing long-term ZES treatment with anti-acid therapies, drug-induced control acid secretory rates were correlated with the presence/absence of VB12 deficiency, determined by assessing serum VB12 levels, measurements of VB12 body stores (blood methylmalonic acid (MMA) and total homocysteine[tHYC]), and other features of ZES. After a mean of 10.2 yrs. of any acid treatment (5.6 yrs. with PPIs), 21% had VB12 deficiency with significantly lower serum and body VB12 levels (p < 0.0001). The presence of VB12 deficiency did not correlate with any feature of ZES but was associated with a 12-fold lower acid control rate, a 2-fold higher acid control pH (6.4 vs. 3.7), and acid control secretory rates below those required for the activation of pepsin (pH > 3.5). Over a 5-yr period, the patients with VB12 deficiency had a higher rate of achlorhydria (73% vs. 24%) and a lower rate of normal acid secretion (0% vs. 49%). In conclusion, in ZES patients, chronic long-term PPI treatment results in marked acid hyposecretion, resulting in decreased serum VB12 levels and decreased VB12-body stores, which can result in VB12 deficiency.

Gastrinoma With Relatively Low Gastrin Levels: A Case Report

Gastrinomas can often be cured with surgical removal if detected early enough. We present a case report where a patient was diagnosed with gastrinoma with relatively low serum gastrin levels after subsequent duodenojejunostomy, gastrojejunostomy, total gastrectomy, and cholecystectomy. With this case report, we hope to promote a higher level of awareness of pancreatic neuroendocrine (NE) tumors and educate clinicians on the full effects of proton pump inhibitor (PPI) use on patient workup, diagnostics, and care.

Successful Lifetime/Long-Term Medical Treatment of Acid Hypersecretion in Zollinger-Ellison Syndrome (ZES): Myth or Fact? Insights from an Analysis of Results of NIH Long-Term Prospective Studies of ZES

Analysis of the efficacy/pharmacology of long-term/lifetime medical treatment of acid hypersecretion in a large cohort of ZES patients in a prospective study. This study includes the results from all 303 patients with established ZES who were prospectively followed and received acid antisecretory treatment with either H2Rs or PPIs, with antisecretory doses individually titrated by the results of regular gastric acid testing. The study includes patients treated for short-term periods (<5 yrs), patients treated long-term (>5 yrs), and patients with lifetime treatment (30%) followed for up to 48 years (mean 14 yrs). Long-term/lifelong acid antisecretory treatment with H2Rs/PPIs can be successfully carried out in all patients with both uncomplicated and complicated ZES (i.e., with MEN1/ZES, previous Billroth 2, severe GERD). This is only possible if drug doses are individually set by assessing acid secretory control to establish proven criteria, with regular reassessments and readjustments. Frequent dose changes both upward and downward are needed, as well as regulation of the dosing frequency, and there is a primary reliance on the use of PPIs. Prognostic factors predicting patients with PPI dose changes are identified, which need to be studied prospectively to develop a useful predictive algorithm that could be clinically useful for tailored long-term/lifetime therapy in these patients.

Combination of esomeprazole and pirfenidone enhances antifibrotic efficacy in vitro and in a mouse model of TGFβ-induced lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease of unknown etiology. Currently, pirfenidone and nintedanib are the only FDA-approved drugs for the treatment of IPF and are now the standard of care. This is a significant step in slowing down the progression of the disease. However, the drugs are unable to stop or reverse established fibrosis. Several retrospective clinical studies indicate that proton pump inhibitors (PPIs; FDA-approved to treat gastroesophageal reflux) are associated with favorable outcomes in patients with IPF, and emerging preclinical studies report that PPIs possess antifibrotic activity. In this study, we evaluated the antifibrotic efficacy of the PPI esomeprazole when combined with pirfenidone in vitro and in vivo. In cell culture studies of IPF lung fibroblasts, we assessed the effect of the combination on several fibrosis-related biological processes including TGFβ-induced cell proliferation, cell migration, cell contraction, and collagen production. In an in vivo study, we used mouse model of TGFβ-induced lung fibrosis to evaluate the antifibrotic efficacy of esomeprazole/pirfenidone combination. We also performed computational studies to understand the molecular mechanisms by which esomeprazole and/or pirfenidone regulate lung fibrosis. We found that esomeprazole significantly enhanced the anti-proliferative effect of pirfenidone and favorably modulated TGFβ-induced cell migration and contraction of collagen gels. We also found that the combination significantly suppressed collagen production in response to TGFβ in comparison to pirfenidone monotherapy. In addition, our animal study demonstrated that the combination therapy effectively inhibited the differentiation of lung fibroblasts into alpha smooth muscle actin (αSMA)-expressing myofibroblasts to attenuate the progression of lung fibrosis. Finally, our bioinformatics study of cells treated with esomeprazole or pirfenidone revealed that the drugs target several extracellular matrix (ECM) related pathways with esomeprazole preferentially targeting collagen family members while pirfenidone targets the keratins. In conclusion, our cell biological, computational, and in vivo studies show that the PPI esomeprazole enhances the antifibrotic efficacy of pirfenidone through complementary molecular mechanisms. This data supports the initiation of prospective clinical studies aimed at repurposing PPIs for the treatment of IPF and other fibrotic lung diseases where pirfenidone is prescribed.

AGA Clinical Practice Update on De-Prescribing of Proton Pump Inhibitors: Expert Review

DESCRIPTION

Proton pump inhibitors (PPIs) are among the most commonly used medications in the world. Developed for the treatment and prevention of acid-mediated upper gastrointestinal conditions, these agents are being used increasingly for indications where their benefits are less certain. PPI overprescription imposes an economic cost and contributes to polypharmacy. In addition, PPI use has been increasingly linked to a number of adverse events (PPI-associated adverse events [PAAEs]). Therefore, de-prescribing of PPIs is an important strategy to lower pill burden while reducing real costs and theoretical risks. The purpose of this clinical update was to provide Best Practice Advice (BPA) statements about how to approach PPI de-prescribing in ambulatory patients.

METHODS

Our guiding principle was that, although PPIs are generally safe, patients should not use any medication when there is not a reasonable expectation of benefit based on scientific evidence or prior treatment response. Prescribers are responsible for determining whether PPI use is absolutely or conditionally indicated and, when uncertainty exists, to incorporate patient perspectives into PPI decision making. We collaboratively outlined a high-level "process map" of the conceptual approach to de-prescribing PPIs in a clinical setting. We identified the following 3 key domains that required BPA guidance: documentation of PPI indication; identifying suitable candidates for consideration of de-prescribing; and optimizing successful de-prescribing. Co-authors drafted 1 or more potential BPAs, supported by literature review, for each domain. All co-authors reviewed, edited, and selected or rejected draft BPAs for inclusion in the final list submitted to the American Gastroenterological Association Governing Board. Because this was not a systematic review, we did not carry out a formal rating of the quality of evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: All patients taking a PPI should have a regular review of the ongoing indications for use and documentation of that indication. This review should be the responsibility of the patient's primary care provider. BEST PRACTICE ADVICE 2: All patients without a definitive indication for chronic PPI should be considered for trial of de-prescribing. BEST PRACTICE ADVICE 3: Most patients with an indication for chronic PPI use who take twice-daily dosing should be considered for step down to once-daily PPI. BEST PRACTICE ADVICE 4: Patients with complicated gastroesophageal reflux disease, such as those with a history of severe erosive esophagitis, esophageal ulcer, or peptic stricture, should generally not be considered for PPI discontinuation. BEST PRACTICE ADVICE 5: Patients with known Barrett's esophagus, eosinophilic esophagitis, or idiopathic pulmonary fibrosis should generally not be considered for a trial of de-prescribing. BEST PRACTICE ADVICE 6: PPI users should be assessed for upper gastrointestinal bleeding risk using an evidence-based strategy before de-prescribing. BEST PRACTICE ADVICE 7: Patients at high risk for upper gastrointestinal bleeding should not be considered for PPI de-prescribing. BEST PRACTICE ADVICE 8: Patients who discontinue long-term PPI therapy should be advised that they may develop transient upper gastrointestinal symptoms due to rebound acid hypersecretion. BEST PRACTICE ADVICE 9: When de-prescribing PPIs, either dose tapering or abrupt discontinuation can be considered. BEST PRACTICE ADVICE 10: The decision to discontinue PPIs should be based solely on the lack of an indication for PPI use, and not because of concern for PAAEs. The presence of a PAAE or a history of a PAAE in a current PPI user is not an independent indication for PPI withdrawal. Similarly, the presence of underlying risk factors for the development of an adverse event associated with PPI use should also not be an independent indication for PPI withdrawal.

Multiple Endocrine Neoplasia Type 1 and the Pancreas: Diagnosis and Treatment of Functioning and Non-Functioning Pancreatic and Duodenal Neuroendocrine Neoplasia within the MEN1 Syndrome - An International Consensus Statement

The better understanding of the biological behavior of multiple endocrine neoplasia type 1 (MEN1) organ manifestations and the increase in clinical experience warrant a revision of previously published guidelines. Duodenopancreatic neuroendocrine neoplasias (DP-NENs) are still the second most common manifestation in MEN1 and, besides NENs of the thymus, remain a leading cause of death. DP-NENs are thus of main interest in the effort to reevaluate recommendations for their diagnosis and treatment. Especially over the last 2 years, more clinical experience has documented the follow-up of treated and untreated (natural-course) DP-NENs. It was the aim of the international consortium of experts in endocrinology, genetics, radiology, surgery, gastroenterology, and oncology to systematically review the literature and to present a consensus statement based on the highest levels of evidence. Reviewing the literature published over the past decade, the focus was on the diagnosis of F- and NF-DP-NENs within the MEN1 syndrome in an effort to further standardize and improve treatment and follow-up, as well as to establish a "logbook" for the diagnosis and treatment of DP-NENs. This shall help further reduce complications and improve long-term treatment results in these rare tumors. The following international consensus statement builds upon the previously published guidelines of 2001 and 2012 and attempts to supplement the recommendations issued by various national and international societies.

The North American Neuroendocrine Tumor Society Consensus Guidelines for Surveillance and Medical Management of Pancreatic Neuroendocrine Tumors

This article is the result of the North American Neuroendocrine Tumor Society consensus conference on the medical management of pancreatic neuroendocrine tumors from July 19 to 20, 2018. The guidelines panel consisted of medical oncologists, pathologists, gastroenterologists, endocrinologists, and radiologists. The panel reviewed a series of questions regarding the medical management of patients with pancreatic neuroendocrine tumors as well as questions regarding surveillance after resection. The available literature was reviewed for each of the question and panel members voted on controversial topics, and the recommendations were included in a document circulated to all panel members for a final approval.

Advances in the Diagnosis and Management of Well-Differentiated Neuroendocrine Neoplasms

Neuroendocrine neoplasms constitute a diverse group of tumors that derive from the sensory and secretory neuroendocrine cells and predominantly arise within the pulmonary and gastrointestinal tracts. The majority of these neoplasms have a well-differentiated grade and are termed neuroendocrine tumors (NETs). This subgroup is characterized by limited proliferation and patients affected by these tumors carry a good to moderate prognosis. A substantial subset of patients presenting with a NET suffer from the consequences of endocrine syndromes as a result of the excessive secretion of amines or peptide hormones, which can impair their quality of life and prognosis. Over the past 15 years, critical developments in tumor grading, diagnostic biomarkers, radionuclide imaging, randomized controlled drug trials, evidence-based guidelines, and superior prognostic outcomes have substantially altered the field of NET care. Here, we review the relevant advances to clinical practice that have significantly upgraded our approach to NET patients, both in diagnostic and in therapeutic options.

Effect of prolonged omeprazole administration on segmental intestinal Mg2+ absorption in male Sprague-Dawley rats

BACKGROUND

The exact mechanism of proton pump inhibitors (PPIs)-induced hypomagnesemia (PPIH) is largely unknown. Previous studies proposed that PPIH is a consequence of intestinal Mg²⁺ malabsorption. However, the mechanism of PPIs-suppressed intestinal Mg²⁺ absorption is under debate.

AIM

To investigate the effect of 12-wk and 24-wk omeprazole injection on the total, transcellular, and paracellular Mg²⁺ absorption in the duodenum, jejunum, ileum, and colon of male Sprague-Dawley rats.

METHODS

The rats received 20 mg/kg∙d subcutaneous omeprazole injection for 12 or 24 wk. Plasma and urinary Mg²⁺, Ca²⁺, and PO₄³⁻ levels were measured. The plasma concentrations of 1α,25-dihydroxyvitamin D₃ (1α,25(OH)₂D₃), parathyroid hormone (PTH), fibroblast growth factor 23 (FGF-23), epidermal growth factor (EGF), and insulin were also observed. The duodenum, jejunum, ileum, and colon of each rat were mounted onto individual modified Using chamber setups to study the rates of total, transcellular, and paracellular Mg²⁺ absorption simultaneously. The expression of transient receptor potential melastatin 6 (TRPM6) and cyclin M4 (CNNM4) in the entire intestinal tract was also measured.

RESULTS

Single-dose omeprazole injection significantly increased the intraluminal pH of the stomach, duodenum, and jejunum. Omeprazole injection for 12 and 24 wk induced hypomagnesemia with reduced urinary Mg²⁺ excretion. The plasma Ca²⁺ was normal but the urinary Ca²⁺ excretion was reduced in rats with PPIH. The plasma and urinary PO₄³⁻ levels increased in PPIH rats. The levels of 1α,25(OH)₂D₃ and FGF-23 increased, whereas that of plasma EGF decreased in the omeprazole-treated rats. The rates of the total, transcellular, and paracellular Mg²⁺ absorption was significantly lower in the duodenum, jejunum, ileum, and colon of the rats with PPIH than in those of the control rats. The percent suppression of Mg²⁺ absorption in the duodenum, jejunum, ileum, and colon of the rats with PPIH compared with the control rats was 81.86%, 70.59%, 69.45%, and 39.25%, respectively. Compared with the control rats, the rats with PPIH had significantly higher TRPM6 and CNNM4 expression levels throughout the intestinal tract.

CONCLUSION

Intestinal Mg²⁺ malabsorption was observed throughout the intestinal tract of rats with PPIH. PPIs mainly suppressed small intestinal Mg²⁺ absorption. Omeprazole exerted no effect on the intraluminal acidic pH in the colon. Thus, the lowest percent suppression of total Mg²⁺ absorption was found in the colon. The expression levels of TRPM6 and CNNM4 increased, indicating the presence of a compensatory response to Mg²⁺ malabsorption in rats with PPIH. Therefore, the small intestine is an appropriate segment that should be modulated to counteract PPIH.

Insights into Effects/Risks of Chronic Hypergastrinemia and Lifelong PPI Treatment in Man Based on Studies of Patients with Zollinger-Ellison Syndrome

The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both for approved indications (peptic ulcer disease, gastroesophageal reflux disease (GERD), Helicobacter pylori eradication regimens, stress ulcer prevention), but are also one of the most frequently off-label used drugs (25–70% of total). An increasing number of patients with moderate to advanced gastroesophageal reflux disease are remaining on PPI indefinitely. Whereas numerous studies show PPIs remain effective and safe, most of these studies are <5 years of duration and little data exist for >10 years of treatment. Recently, based primarily on observational/epidemiological studies, there have been an increasing number of reports raising issues about safety and side-effects with very long-term chronic treatment. Some of these safety issues are related to the possible long-term effects of chronic hypergastrinemia, which occurs in all patients taking chronic PPIs, others are related to the hypo-/achlorhydria that frequently occurs with chronic PPI treatment, and in others the mechanisms are unclear. These issues have raised considerable controversy in large part because of lack of long-term PPI treatment data (>10–20 years). Zollinger–Ellison syndrome (ZES) is caused by ectopic secretion of gastrin from a neuroendocrine tumor resulting in severe acid hypersecretion requiring life-long antisecretory treatment with PPIs, which are the drugs of choice. Because in <30% of patients with ZES, a long-term cure is not possible, these patients have life-long hypergastrinemia and require life-long treatment with PPIs. Therefore, ZES patients have been proposed as a good model of the long-term effects of hypergastrinemia in man as well as the effects/side-effects of very long-term PPI treatment. In this article, the insights from studies on ZES into these controversial issues with pertinence to chronic PPI use in non-ZES patients is reviewed, primarily concentrating on data from the prospective long-term studies of ZES patients at NIH.

Diagnosis of Zollinger-Ellison syndrome in the era of PPIs, faulty gastrin assays, sensitive imaging and limited access to acid secretory testing

In recent years the diagnosis of Zollinger-Ellison syndrome (ZES) has become increasingly controversial with several new approaches and criteria proposed, differing from the classical biochemical criterion of inappropriate hypergastrinemia (i.e., hypergastrinemia in the presence of hyperchlorhydria) (Table 1). These changes have come about because of the difficulty and potential dangers of stopping proton pump inhibitors (PPIs) for gastric acid analysis; the recognition than many of the current assays used to assess gastrin concentrations are unreliable; the development of sensitive imaging modalities that detect neuroendocrine tumors (NETs) including an increasing number of the primary gastrinomas; the increased use of percutaneous or endoscopic ultrasound (EUS)-directed biopsies/cytology and the general lack of availability of acid secretory testing. In this article we will discuss the basis for these controversies, review the proposed changes in diagnostic approaches and make recommendations for supporting the diagnosis of ZES in the modern era.

The Indications, Applications, and Risks of Proton Pump Inhibitors

BACKGROUND

Proton pump inhibitors (PPI) are the most effective drugs for inhibiting gastric acid secretion. They have been in clinical use for more than 25 years, In 2014, 3.475 billion daily defined doses (DDD) of PPI were prescribed in Germany. This high number alone calls for a critical analysis of the spectrum of indications for PPI and their potential adverse effects.

METHODS

This review is based on pertinent publications retrieved by a selective search in the PubMed and Cochrane Library databases, with particular emphasis on randomized, prospective multicenter trials, cohort studies, case-control studies, and meta-analyses.

RESULTS

The inhibition of gastric acid secretion with PPI is successfully used for the treatment of gastroesophageal reflux disease and of gastric and duodenal ulcers, for the secondary prevention of gastroduodenal lesions that have arisen under treatment with nonsteroidal anti-inflammatory drugs and acetylsalicylic acid, and for the prevention of recurrent hemorrhage from ulcers after successful endoscopic hemostasis. PPI are given along with practically all antibiotic regimens for the eradication of Helicobacter pylori infection. The number of prescriptions for PPI has risen linearly over the past 25 years. As there has been no broadening of indications, one may well ask whether the current, extensive use of PPI is justified. There is evidence that patients taking PPI are at greater risk for fractures. Moreover, the vitamin B12 level should be checked occasionally in all patients taking PPI.

CONCLUSION

PPI are among the more effective drugs for the treatment of diseases associated with gastric acid. In view of their cost and potential adverse effects, they should only be prescribed for scientifically validated indications.

Gastric Hypersecretory States: Investigation and Management

OPINION STATEMENT

Hypersecretory conditions affecting the stomach account for significant morbidity and mortality manifested in some cases with peptic ulcer, gastrointestinal hemorrhage, and/or gastroesophageal reflux disease (GERD). The diagnosis of gastric acid hypersecretory states can be challenging and relies on the use of quantitative assays to measure gastric acid secretion and serum gastrin. The most common etiology for hypergastrinemia is the use of potent gastric acid inhibitors such as the proton pump inhibitors. The differential diagnosis of this condition is of critical importance, and will dictate management decisions. Conditions such as atrophic gastritis are relatively benign and can lead to hypergastrinemia without the presence of gastric acid hypersecretion. Zollinger-Ellison syndrome, on the other hand, causes hypergastrinemia with profound gastric acid hypersecretion [1]. More common causes of hypergastrinemia include gastric outlet obstruction, ileus, and chronic renal failure [2]. In most cases, proton pump inhibitors will be used to manage these conditions. In some instances, surgical therapy may be required. This chapter will review the important clinical causes of gastric acid hypersecretion and provide insights to the best medical management options to better care for patients with these disorders.

Clinical predictors associated with proton pump inhibitor-induced hypomagnesemia

There is increasing evidence and case reports regarding proton pump inhibitor (PPI)-induced hypomagnesemia. Our study aimed to clarify the relationship between PPI use and serum magnesium levels and to specify high-risk patients. We retrospectively studied 112 consecutive patients aged 20 years or older who were treated with PPI for ≥30 days and whose serum magnesium levels were available for the PPI treatment period. We compared the mean level of serum magnesium of the enrolled patients with PPI treatment with matched controls. There were no significant differences between the matched PPI users (n = 105) and nonusers (n = 210) in the magnesium levels (0.85 ± 0.09 vs. 0.86 ± 0.16 mM, P = 0.297). In a subgroup analysis of a PPI user group, hypomagnesemia could be observed in 32 patients but not in 80 patients. In multivariate analyses, PPI use for >1 year, age less than 45 years, and concurrent cisplatin or carboplatin use were significantly associated with PPI-induced hypomagnesemia {P = 0.042, odds ratio [OR; 95% confidence interval (CI)]: 5.388 [1.056-27.493]; P = 0.007, OR [95% CI]: 4.710 [1.523-14.571]; P = 0.007, OR [95% CI]: 13.404 [2.066-86.952], respectively} after adjusting for confounders. This study shows that long-term PPI use is associated with hypomagnesemia in hospitalized adult patients. Therefore, serum magnesium levels should be checked before the initiation of PPI treatment and during the treatment period in patients, particularly those concurrently using platinum-based chemotherapy or who are expected to use PPI for long periods.

Impact of proton pump inhibitor use on magnesium homoeostasis: a cross-sectional study in a tertiary emergency department

BACKGROUND

To date, the use of proton pump inhibitors (PPIs) has been associated with a low risk of hypomagnesaemia and associated adverse outcomes. We hypothesised that a better risk estimate could be derived from a large cohort of outpatients admitted to a tertiary emergency department (ED).

METHODS

A cross-sectional study was performed in 5118 patients who had measurements of serum magnesium taken on admission to a large tertiary care ED between January 2009 and December 2010. Hypomagnesaemia was defined as a serum magnesium concentration < 0.75 mmol/l. Demographical data, serum electrolyte values, data on medication, comorbidities and outcome with regard to length of hospital stay and mortality were analysed.

RESULTS

Serum magnesium was normally distributed where upon 1246 patients (24%) were hypomagnesaemic. These patients had a higher prevalence of out-of-hospital PPI use and diuretic use when compared with patients with magnesium levels > 0.75 mmol/l (both p < 0.0001). In multivariable regression analyses adjusted for PPIs, diuretics, renal function and the Charlson comorbidity index score, the association between use of PPIs and risk for hypomagnesaemia remained significant (OR = 2.1; 95% CI: 1.54-2.85). While mortality was not directly related to low magnesium levels (p = 0.67), the length of hospitalisation was prolonged in these patients even after adjustment for underlying comorbid conditions (p < 0.0001).

CONCLUSION

Use of PPIs predisposes patients to hypomagnesaemia and such to prolonged hospitalisation irrespective of the underlying morbidity, posing a critical concern.

Hypomagnesemia in the intensive care unit: Choosing your gastrointestinal prophylaxis, a case report and review of the literature

We report a case of symptomatic hypomagnesaemia in medical intensive care unit that is strongly related to proton pump inhibitors (PPIs) and provide literature review. A 65-year-old male with severe gastroesophageal reflux on omeprazole 20 mg orally twice a day, who presented to the hospital with abdominal pain, nausea, diarrhea, and new onset seizures. On admission, his serum magnesium level was undetectable. Electrocardiogram showed a new right bundle branch block with a prolonged QT interval. The hypomagnesemia was corrected with aggressive magnesium supplementation and hypomagnesemia resolved only after the PPI was stopped. Neurologic and cardiac abnormalities were corrected. This is a life-threatening case of an undetectable magnesium level strongly associated with PPI use. In critically, ill patients with refractory hypomagnesemia, we advocate considering changing gastrointestinal prophylaxis from a PPI to a histamine-receptor blocker.

Perils and pitfalls of long-term effects of proton pump inhibitors

This review summarizes the literature regarding long-term adverse effects of proton pump inhibitors (PPIs). A PubMed search (1966 to February 2013) for English language studies was conducted using key terms PPI: omeprazole, esomeprazole, pantoprazole, lansoprazole, dexlansoprazole, rabeprazole, pneumonia, Clostridium difficile, osteoporosis, risk of fractures, thrombocytopenia, rhabdomyolysis, anemia, iron deficiency, hypomagnesemia, vitamin B₁₂ and nephritis. The risk of pneumonia was increased 27-39% in short-term use of PPIs in three meta-analyses. C. difficile infections were also associated with the use of PPIs (odds ratio: 2.15; 95% CI: 1.81-2.55; p < 0.00001). This effect appears to be dose related. The US FDA has recently issued a warning regarding fractures and the impaired magnesium absorption associated with the use of PPI. Thrombocytopenia, iron deficiency, vitamin B12 deficiency, rhabdomyolysis and acute interstitial nephritis have also been reported with the use of PPIs. There is mounting evidence that PPIs are associated with serious adverse effects. Practitioners should be vigilant and counsel patients accordingly.

Hypomagnesemia and proton-pump inhibitors

INTRODUCTION

Proton pump inhibitors (PPIs) have been linked to clinically symptomatic hypomagnesemia.

AREAS COVERED

We searched Medline database in all languages using 'proton-pump inhibitors, magnesium, hypomagnesemia and hypomagnesemic hypoparathyroidism' as search terms and other articles were identified through searches of the files of the authors and reference lists from relevant articles. All patients presented with hypomagnesemic hypoparathyroidism, however, they rarely had life-threatening conditions such as malignant ventricular arrhythmias associated with prolonged QT interval, tetany and generalized seizures. Hypomagnesemia was seen with different PPIs, which could suggest a class effect, and was refractory to Mg replacement until PPIs were stopped. Hypomagnesemia may recur after re-challenge with the same or a different PPI and is not clearly dose-related. Mechanisms are poorly understood but PPI-induced hypochlorhydria does not seem involved. Carriers of TRPM6/7 mutations could be at risk.

EXPERT OPINION

Although mechanism and incidence rate remain unclear, there seems little doubt that PPIs may cause hypomagnesemia. We should obtain blood Mg levels prior to initiation of PPIs when patients are expected to be on treatment for long period of time and in those with other potential causes of hypomagnesemia. Use of H2-blockers may be an appropriate alternative.

Effects of proton pump inhibitors and electrolyte disturbances on arrhythmias

Several case reports have been written regarding the relationship between the use of proton pump inhibitors (PPI) and hypomagnesemia. Some of these reported cases have electrocardiogram abnormalities where electrolytes deficiencies were the contributing factor for these events. This study investigates the correlation between different arrhythmias and the use of PPI and hypomagnesaemia incidence. Four-hundred and twenty-one patients admitted to the critical care unit with unstable angina, non-ST elevation myocardial infarction, and ST-elevation myocardial infarction were included in this study. One-hundred and eighty-four patients (43.8%) received PPI and 237 patients (51.16%) did not, magnesium levels were low (<1.8 mg/dL) in 95 patients (22.5%), and 167 patients (39.6%) developed arrhythmias. The P-values for the regression coefficient association for the use of PPI and the level of magnesium were P = 1.31e(-29) and P = 8e(-102), respectively. The P-values indicate that there is a statistically significant association between the PPI use, magnesium levels, and the occurrence of cardiovascular events, with a strong correlation factor of 0.817. Patients receiving PPIs should be followed closely for magnesium deficiency, especially if they experience acute cardiovascular events, because this may contribute to worsening arrhythmias and further complications.

Efficacy and safety of proton pump inhibitors in the management of pediatric gastroesophageal reflux disease

Proton pump inhibitors (PPIs) are commonly prescribed to infants and children for managing gastroesophageal reflux disease (GERD). Recently published literature illustrates conflicting evidence on the efficacy of PPIs in infants and children. Randomized controlled trials and systematic reviews have demonstrated a lack of efficacy of PPIs, specifically in young infants. Furthermore, emerging evidence also suggests that PPIs are not as benign as once thought, with newer data implicating a potential association of PPIs with an increased risk of respiratory tract infections, gastrointestinal infections, bone fractures, hypomagnesemia, and the occurrence of rebound hyperacidity after discontinuation of PPI therapy. To summarize the emerging data in children, we reviewed the literature to assess the efficacy and safety of PPIs in managing pediatric GERD. Despite conflicting evidence on the efficacy of PPIs, most studies in children demonstrated some benefit when compared with placebo. With respect to the safety of PPIs in children, only a few small studies and case reports indicated a potential association of PPIs with an increased risk of respiratory tract or gastrointestinal infections, bone fractures, and hypomagnesemia; however, many of those studies had their own limitations. From the review, it is clear that further well-designed trials and observational studies are needed to shed more light on the efficacy and safety of PPIs in the pediatric population.

Out-of-hospital use of proton pump inhibitors and hypomagnesemia at hospital admission: a nested case-control study

BACKGROUND

Case series suggest that long-term use of proton pump inhibitors (PPIs) is associated with hypomagnesemia, but the current literature lacks systematically collected data. Our aim was to examine whether hypomagnesemia at the time of hospital admission is associated with out-of-hospital use of PPIs.

STUDY DESIGN

Nested case-control study matched for age and sex.

SETTING & PARTICIPANTS

Data were collected retrospectively from a tertiary acute-care facility. Eligible cases consisted of 402 adults with hypomagnesemia (serum magnesium <1.4 mEq/L) at the time of hospital admission to medical services, age- and sex-matched with 402 control individuals with normal serum magnesium levels (1.4-2.0 mEq/L).

PREDICTOR

Out-of-hospital PPI use was identified in the hospital record. An omeprazole equivalent dose was calculated when possible. Covariates included the Charlson-Deyo comorbidity index, diabetes, diuretic use, estimated glomerular filtration rate, and gastroesophageal reflux.

OUTCOME

Multivariable conditional logistic regression analyses were used to examine the association of PPI use with hypomagnesemia at the time of hospital admission.

RESULTS

PPI use was not associated with hypomagnesemia (adjusted OR, 0.82; 95% CI, 0.61-1.11). Neither PPI type nor omeprazole equivalent daily dose was associated with hypomagnesemia. Sensitivity analyses of PPI use restricted to patients with esophageal disorders (adjusted OR, 1.00; 95% CI, 0.69-1.45), severe hypomagnesemia (magnesium, ≤1.0 mEq/L; adjusted OR, 0.78; 95% CI, 0.13-4.61), or estimated glomerular filtration rate ≥60 mL/min/1.73 m(2) (adjusted OR, 0.84; 95% CI, 0.53-1.34) were unrevealing.

LIMITATIONS

Exposure misclassification; hospitalized patients on medical services may not be representative of a broader ambulatory-based population.

CONCLUSIONS

In a hospital-based adult population, out-of-hospital PPI use is not associated with hypomagnesemia at the time of hospital admission to medical services. In light of these inconclusive results, prospective cohort studies are needed to address this rare potential medication-related adverse effect.

Proton pump inhibitor-associated hypomagnesemia: what do FDA data tell us?

BACKGROUND

Proton pump inhibitors (PPIs) are a class of medications indicated for the treatment of gastric acid-related diseases. Hypomagnesemia is a rare but serious adverse effect of PPIs.

OBJECTIVE

To address the association between the use of different PPIs and hypomagnesemia by examining the frequency of occurrence of hypo magnesemia among the reported adverse drug reactions from the Food and Drug Administration (FDA) Adverse Event Reporting System database.

METHODS

We conducted a cross-sectional study of PPI-associated adverse effect cases reported to the FDA between November 1, 1997, and April 1, 2012. Logistic regression was used to examine the association of sex, age, and different PPIs with hypomagnesemia. χ² analysis was conducted to investigate the association of PPI-associated hypomagnesemia with hypocalcemia and hypokalemia.

RESULTS

Among 66,102 subjects identified as experiencing 1 or more adverse effects while taking a PPI, 1.0% (n = 693) were reported to have hypomagnesemia. The mean (SD) age of PPI users presenting with hypomagnesemia was 64.4 (12.9) years. Results from logistic regression indicated that, compared with esomeprazole, all other PPIs had a higher rate of hypomagnesemia, with pantoprazole having the highest rate (OR 4.3; 95% CI 3.3-5.7; p < 0.001). The risk of female subjects having hypo magnesemia (OR 0.83; 95% CI 0.71-0.97; p = 0.016) was significantly lower than that of males. Elderly subjects (age >65 years) were at increased risk of PPI-associated hypomagnesemia (OR 1.5; 95% CI 1.2-1.7; p < 0.001). χ² analysis showed strong association between hypomagnesemia and both hypocalcemia (p < 0.001) and hypokalemia (p < 0.001).

CONCLUSIONS

All PPIs were associated with hypomagnesemia, with esomeprazole having the lowest risk and pantoprazole having the highest risk. The risk of PPI-associated hypomagnesemia was higher in males and the elderly population. Hypocalcemia and hypokalemia commonly coexisted with PPI-associated hypomagnesemia.

Pharmacotherapy of Zollinger-Ellison syndrome

INTRODUCTION

The role of pharmacotherapy in the management of patients with Zollinger-Ellison syndrome (ZES) is often equated with the medical management of acid hypersecretion. However, pharmacotherapy is also increasingly involved in the other management areas of these patients.

AREAS COVERED

This paper reviews the role of pharmacotherapy in all aspects of the management of patients with ZES. Newer aspects are emphasized. This includes the difficulty of diagnosing ZES in patients taking proton pump inhibitors. Also covered is the role of pharmacotherapy in controlling acid hypersecretion and other hormonal hypersecretory states these patients may develop, including hyperparathyroidism in patients with multiple endocrine neoplasia type 1 and ZES; tumor localization; and the treatment of advanced metastatic disease. The last includes chemotherapy, liver-directed therapies, biotherapy (somatostatin/interferon), peptide radio-receptor therapy and molecular-targeted therapies including the use of mTor inhibitors (everolimus) and tyrosine kinase inhibitors (sunitinib).

EXPERT OPINION

Pharmacotherapy is now involved in all aspects of the management of patients with ZES, with the result that ZES has progressed from being considered an entirely surgical disease initially to the present where medical treatment plays a major role in almost all aspects of the management of these patients.

Proton-pump inhibitor use is associated with low serum magnesium concentrations

Although case reports link proton-pump inhibitor (PPI) use and hypomagnesemia, no large-scale studies have been conducted. Here we examined the serum magnesium concentration and the likelihood of hypomagnesemia (<1.6 mg/dl) with a history of PPI or histamine-2 receptor antagonist used to reduce gastric acid, or use of neither among 11,490 consecutive adult admissions to an intensive care unit of a tertiary medical center. Of these, 2632 patients reported PPI use prior to admission, while 657 patients were using a histamine-2 receptor antagonist. PPI use was associated with 0.012 mg/dl lower adjusted serum magnesium concentration compared to users of no acid-suppressive medications, but this effect was restricted to those patients taking diuretics. Among the 3286 patients concurrently on diuretics, PPI use was associated with a significant increase of hypomagnesemia (odds ratio 1.54) and 0.028 mg/dl lower serum magnesium concentration. Among those not using diuretics, PPI use was not associated with serum magnesium levels. Histamine-2 receptor antagonist use was not significantly associated with magnesium concentration without or with diuretic use. The use of PPI was not associated with serum phosphate concentration regardless of diuretic use. Thus, we verify case reports of the association between PPI use and hypomagnesemia in those concurrently taking diuretics. Hence, serum magnesium concentrations should be followed in susceptible individuals on chronic PPI therapy.

Modeling and simulation of the effect of proton pump inhibitors on magnesium homeostasis. 1. Oral absorption of magnesium

Prolonged use of proton pump inhibitors has reportedly caused rare clinically symptomatic hypomagnesemia. A review of the literature suggests PPI drugs may impair intestinal magnesium absorption. With the goal of preventing PPI-induced hypomagnesemia, an oral absorption-centric model was developed by referencing literature data. Our modeling with human data reveals that magnesium absorption is substantial in the distal intestine. We then perform simulations by referring to the reported reduction in mid to distal intestinal pH caused by one week of oral esomeprazole, and to reported reduction of the divalent cation-sensitive current when the carboxyl side chains of glutamic and aspartic residues in the binding channels of TRPM6/TRPM7 were neutralized. Our simulations reveal that short-term PPI therapy may cause a very small reduction (5%) in the serum magnesium level, which is qualitatively consistent with the reported 1% reduction in magnesium absorption following 1 week of omeprazole in humans. Simulations provide insight into the benefit of frequent but small dose of magnesium supplementation in maintaining the serum magnesium level when magnesium deficiency occurs.

Systematic review: hypomagnesaemia induced by proton pump inhibition

BACKGROUND

Proton pump inhibitors (PPIs) are a mainstay therapy for all gastric acid-related diseases. Clinical concerns arise from a small but growing number of case reports presenting PPI-induced hypomagnesaemia (PPIH) as a consequence of long-term PPI use. Current opinion is that reduced intestinal magnesium absorption might be involved, but nothing is known on the molecular mechanism underlying PPIH.

AIM

To investigate whether or not PPIH is a true, long-term drug-class effect of all PPIs and to scrutinise a possible role of comorbidity in its aetiology. Therefore, the primary objective in particular was to investigate serum magnesium dynamics in trials drug withdrawal and re-challenge. The secondary objective was to profile the 'patient at risk'.

METHODS

We reviewed systematically all currently available case reports on the subject and performed a statistical analysis on extracted data.

RESULTS

Proton pump inhibitor-induced hypomagnesaemia PPIH is a drug-class effect and occurred after 5.5 years (median) of PPI use, onset was broad and ranged from 14 days to 13 years. Discontinuation of PPIs resulted in fast recovery from PPIH in 4 days and re-challenge led to reoccurrence within 4 days. Histamine-2-receptor antagonists were the preferable replacement therapy in PPIH and prevented reoccurrence of hypomagnesaemia. In PPIH no specific risk profile was identified that was linked to the hypomagnesaemia.

CONCLUSIONS

The cases of PPIH show severe symptoms of magnesium depletion and identification of its causation was only possible through withdrawal of the PPI. Clinical awareness of PPIH is key to avoid putting patients at risk.

Recent safety concerns with proton pump inhibitors

There have been recent concerns about the safety of proton pump inhibitors (PPIs). We focus here on 3 specific concerns-the possible interaction between PPIs and clopidogrel, the postulated link between PPI use and fractures, and the possibility that long-term PPI use might lead to hypomagnesemia. There is evidence for an in vitro interaction between clopidogrel and at least some PPIs. The Food and Drug Administration (FDA) has warned against the use of certain PPIs by patients on clopidogrel. However, a randomized controlled trial that compared clopidogrel alone with the combination of clopidogrel and omeprazole found no increase in adverse cardiovascular outcomes and a reduction in the rate of adverse gastrointestinal outcomes attributable to omeprazole. PPI use may be a weak risk factor for certain fractures, but the quality of evidence is relatively poor and there is a strong possibility of confounding. The mechanism whereby PPI use might increase fracture risk is unknown. Currently, no additional measures concerning calcium supplementation or bone mineral density monitoring are recommended for patients on a PPI. The FDA has suggested monitoring serum magnesium levels in patients on PPI therapy. The mechanism and frequency of PPI-induced hypomagnesemia are unclear. PPI treatment should not be withheld from patients who genuinely require it, but the PPI should be taken in the lowest effective dose and only for as long as clinically indicated. The same is, of course, true for all medicines. The benefits of PPI therapy greatly outweigh the risks.

Omeprazole- and esomeprazole-associated hypomagnesaemia: data mining of the public version of the FDA Adverse Event Reporting System

OBJECTIVE

Case reports showing that proton-pump inhibitors (PPIs), omeprazole and esomeprazole, can cause hypomagnesaemia have been accumulating since 2006. In this study, the reports submitted to the Adverse Event Reporting System (AERS) of the US Food and Drug Administration (FDA) were evaluated to assess omeprazole and esomeprazole in terms of susceptibility to hypomagnesaemia.

METHODS

After a revision of arbitrary drug names and the deletion of duplicated submissions, the reports involving omeprazole and esomeprazole were analyzed. Standardized official pharmacovigilance tools were used for the quantitative detection of a signal, i.e., an association between a drug and an adverse drug event, including the proportional reporting ratio, the reporting odds ratio, the information component given by a Bayesian confidence propagation neural network, and the empirical Bayes geometric mean.

RESULTS

A total of 22,017,956 co-occurrences were found in 1,644,220 reports from 2004 to 2009, where a co-occurrence was a pair of a drug and an adverse drug event. In total, 818 and 743 adverse drug events were listed as omeprazole- and esomeprazole-associated, with hypomagnesaemia ranking 85th and 135th, respectively. Although both PPIs were associated with hypomagnesaemia, the statistical metrics suggested that the association was more noteworthy for omeprazole.

CONCLUSION

The data obtained in this study do not provide sufficient evidence to recommend systematic monitoring of magnesium levels in plasma, but chronic exposure to a PPI can lead to severe hypomagnesaemia.

Zollinger-Ellison syndrome: presentation, response to therapy, and outcome

BACKGROUND

Recent series describing the clinical presentation, response to therapy, and long-term outcome of Zollinger-Ellison syndrome are limited.

AIMS

To assess the clinical characteristics and long-term outcome of patients with Zollinger-Ellison syndrome.

METHODS

Over a 20-year period, patients with Zollinger-Ellison syndrome were enrolled in a prospective trial evaluating the efficacy of lansoprazole. Following dose stabilization, patients were followed on a 6-monthly basis with interval history, physical examination, endoscopy with gastric biopsies, gastric acid analysis and laboratory studies.

RESULTS

72 patients (mean age 54±12 years, % male 58%, % Caucasian 69%) were prospectively enrolled. The clinical presentation was stereotypical for Zollinger-Ellison syndrome. Symptoms had been reported for a median of 9 years prior to diagnosis. Cross-sectional abdominal imaging was often negative for demonstrable tumour. All patients had gastric acid hypersecretion controlled with variable doses of lansoprazole (median dose 60 mg/day, range 15-480 mg/day). The median survival from the time of diagnosis was 6.6 years; only two of 19 deaths were due to metastatic gastrinoma.

CONCLUSIONS

The clinical presentation of Zollinger-Ellison syndrome was similar to prior reports. Acid hypersecretion was controlled in all patients with variable doses of lansoprazole. Long-term survival was principally related to underlying co-morbidity.

Adverse effects of long-term proton pump inhibitor therapy

Proton pump inhibitors have an excellent safety profile and have become one of the most commonly prescribed class of drugs in primary and specialty care. Long-term, sometimes lifetime, use is becoming increasingly common, often without appropriate indications. This paper is a detailed review of the current evidence on this important topic, focusing on the potential adverse effects of long-term proton pump inhibitor use that have generated the greatest concern: B12 deficiency; iron deficiency; hypomagnesemia; increased susceptibility to pneumonia, enteric infections, and fractures; hypergastrinemia and cancer; drug interactions; and birth defects. We explain the pathophysiological mechanisms that may underlie each of these relationships, review the existing evidence, and discuss implications for clinical management. The benefits of proton pump inhibitor use outweigh its risks in most patients. Elderly, malnourished, immune-compromised, chronically ill, and osteoporotic patients theoretically could be at increased risk from long-term therapy.

Proton pump inhibitors and severe hypomagnesaemia

PURPOSE OF REVIEW

Hypomagnesaemia has recently been recognized as a rare, but severe, complication of proton pump inhibitor (PPI) use. We reviewed all the cases published to date in peer-reviewed journals to summarize what is known of the epidemiology, risk factors, cause and treatment.

RECENT FINDINGS

Hypomagnesaemia has been described with all substituted pyridylmethylsulphonyl benzimidazadole derivatives and is a class effect, recurring with substitution of one PPI for another. A long duration of use and high rates of adherence are probably risk factors, but the prevalence is unknown. The diagnosis is often missed, despite the severe symptomatology. Renal magnesium handling is normal, so implicating impairment of net intestinal absorption as the proximate cause. It is not known whether this is the consequence of defective absorption of magnesium through the active or passive transport processes, or increased losses.

SUMMARY

PPI-associated hypomagnesaemia is a rare, but potentially life-threatening, side-effect that has emerged only in the era of mass use of these agents. The cause of hypomagnesaemia remains poorly understood, but it responds rapidly to withdrawal of the PPI.

Pancreatic endocrine tumors

Pancreatic endocrine tumors have been steadily growing in incidence and prevalence during the last two decades, showing an incidence of 4-5/1,000,000 population. They represent a heterogeneous group with very varying tumor biology and prognosis. About half of the patients present clinical symptoms and syndromes related to substances released from the tumors (Zollinger-Ellison syndrome, insulinoma, glucagonoma, etc) and the other half are so-called nonfunctioning tumors mainly presenting with symptoms such as obstruction, jaundice, bleeding, and abdominal mass. Ten percent to 15% of the pancreatic endocrine tumors are part of an inherited syndrome such as multiple endocrine neoplasia type 1 (MEN-1), von Hippel-Lindau (VHL), neurofibromatosis, or tuberousclerosis. The diagnosis is based on histopathology demonstrating neuroendocrine features such as positive staining for chromogranin A and specific hormones such as gastrin, proinsulin, and glucagon. Moreover, the biochemical diagnosis includes measurement of chromogranins A and B or specific hormones such as gastrin, insulin, glucagon, and vasoactive intestinal polypeptide (VIP) in the circulation. In addition to standard localization procedures, radiology (computed tomography [CT] scan, magnetic resonance imaging [MRI], ultrasound [US]), somatostatin receptor scintigraphy, and most recently positron emission tomography with specific isotopes such as (11)C-5 hydroxytryptamin ((11)C-5-HTP), fluorodopa and (68)Ga-1,4,7,10-tetra-azacyclododecane-N,N',N″,N‴-tetra-acetic acid (DOTA)-octreotate are performed. Surgery is still one of the cornerstones in the management of pancreatic endocrine tumors, but curative surgery is rarely obtained in most cases because of metastatic disease. Debulking and other cytoreductive procedures might facilitate systemic treatment. Cytotoxic drugs, biological agents, such as somatostatin analogs, alpha interferons, mammalian target of rapamycin (mTOR) inhibitors and tyrosine kinase inhibitors are routinely used. Tumor-targeted radioactive treatment is available in many centres in Europe and is effective in patients with tumors that express high content of somatostatin receptors type 2 and 5. In the future, treatment will be based on tumor biology and molecular genetics with the aim of so-called personalized medicine.

Intravenous esomeprazole pharmacodynamics in critically ill patients

OBJECTIVE

A widely held belief contends that food-induced proton pump activation is important for optimal proton pump inhibitor-induced inhibition of gastric acid secretion. This study was undertaken to assess intragastric acid control with intravenous (IV) esomeprazole in critically ill patients.

RESEARCH DESIGN AND METHODS

This open-label, single-arm, exploratory trial was conducted at five university or regional hospital intensive care units in the US. Adult patients admitted to an intensive care unit who required mechanical ventilation and had at least one additional risk factor for stress-induced ulcer received twice-daily IV esomeprazole 40 mg for 48 hours and could continue for another 24 hours if no prepyloric enteral feedings were planned.

CLINICAL TRIAL REGISTRATION

D9612L00107; ClinicalTrials.gov Identifier NCT00428701.

MAIN OUTCOME MEASURES

The primary efficacy variable was the linear-interpolated percentage of time intragastric pH was > or =4 during 24-48 hours. Secondary efficacy variables included the interpolated percentage of time intragastric pH was > or =4 during 0-24, 0-48, and 48-72 hours, the percentage of gastric aspirates collected with pH > or =4 during 0-24, 24-48, 0-48, and 48-72 hours, and time to stable pH > or =4. Safety was assessed based on adverse events (AEs), physical examinations, vital signs, laboratory tests, and electrocardiograms.

RESULTS

Forty-five patients were enrolled (one was excluded because of previous partial gastrectomy). Interpolated mean percentage time pH > or =4 was 88.8%, 80.7%, and 83.5% for 24-48, 0-24, and 0-48 hours, respectively. For 0-72 hours, > or =78% of gastric aspirates had pH > or =4. Median time to stable pH was 1 hour (95% confidence interval: 0.67, 2.00). Treatment was well tolerated, with no evidence of gastrointestinal bleeding. A total of 75 AEs occurred in 34 patients, none considered treatment related.

CONCLUSIONS

In this noncontrolled exploratory study, twice-daily IV esomeprazole 40 mg rapidly decreased intragastric acidity and effectively maintained pH >/=4 during 0-72 hours in fasting, critically ill, mechanically ventilated patients at high risk for stress ulcers.

Gastric acid hypersecretory states: recent insights and advances

Gastric acid hypersecretory states are characterized by basal hypersecretion of gastric acid and historically include disorders associated with hypergastrinemia, hyperhistaminemia, and those of unknown etiology. Although gastric acid secretion is infrequently measured, it is important to recognize the role of gastric hypersecretion in the symptoms of these disorders because they share several features of pathogenesis and treatment. In this article, recent important articles reporting insights into their diagnosis, pathogenesis, and treatment are reviewed. Particular attention is paid to Zollinger-Ellison syndrome, because it has the most extreme acid hypersecretion of this group of disorders and because numerous recent articles deal with various aspects of the diagnosis, molecular pathogenesis, and treatment of the gastrinoma itself or the acid hypersecretion. Two new hypersecretory disorders are reviewed: rebound acid hypersecretion after the use of proton pump inhibitors and acid hypersecretion with cysteamine treatment in children with cystinosis.

Severe hypomagnesaemia due to lansoprazole

A 71-year-old woman, who had been taking lansoprazole for 18 months for dyspepsia, presented with vomiting, thought to be due to gallstones, and was found to have severe hypomagnesaemia. She was treated with intravenous and then oral magnesium, and discharged, but was soon readmitted with symptoms due to hypomagnesaemia, and again treated with magnesium supplementation. No other recognised cause for hypomagnesaemia was found. Because of recent reports of hypomagnesaemia due to other proton pump inhibitors, lansoprazole was changed to ranitidine. Her symptoms resolved and the serum magnesium returned to normal. Oral magnesium supplementation was stopped with no return of symptoms or hypomagnesaemia. Such an association must be borne in mind with suggestive symptoms in patients on long term proton pump inhibitors; their cessation or change to H(2) receptor antagonists is likely to correct the situation rapidly.

The pharmacology of esomeprazole and its role in gastric acid related diseases

Esomeprazole (S-isomer of omeprazole) demonstrates a better pharmacokinetic/pharmacodynamic profile than the racemic product omeprazole. Esomeprazole's pharmacological activity of gastric acid secretion is through proton pump inhibition. The pharmacokinetic properties provide for an enhanced pharmacological effect. Esomeprazole is rapidly absorbed and the extent of absorption is higher resulting in higher systemic absorption of esomeprazole (bioavailability), which coupled with reduced clearance results in greater systemic exposure. This pharmacodynamic profile then provides for a prolongation of inhibition of gastric acid output and correlates well with its more beneficial therapeutic efficacy over omeprazole and some of the other proton-pump inhibitors. It has been well proven as an effective agent in the treatment of gastro-esophagitis reflux disease, (reflux esophagitis and non-erosive reflux disease), NSAID-induced gastric-intestinal symptoms and ulcers, Helicobacter pylori infection and Zollinger-Ellison syndrome. Esomeprazole has a good tolerability profile and a low potential for drug interaction.

PPI-delayed diagnosis of gastrinoma: oncologic victim of pharmacologic success

Functional neuroendocrine tumors are often low-grade malignant neoplasms that can be cured by surgery if detected early, and such detection may in turn be accelerated by the recognition of neuropeptide hypersecretion syndromes. Uniquely, however, relief of peptic symptoms induced by hypergastrinemia is now available from acid-suppressive drugs such as proton-pump inhibitors (PPIs). Here we describe a clinical case in which time to diagnosis from the onset of peptic symptoms was delayed more than 10 years, in part reflecting symptom masking by continuous prescription of the PPI omeprazole. We propose diagnostic criteria for this under-recognized new clinical syndrome, and recommend that physicians routinely measure serum gastrin levels in persistent cases of PPI-dependent dyspepsia unassociated with H. pylori.

Advances in the clinical applications of esomeprazole

Esomeprazole is the first proton pump inhibitor (PPI) to be developed as a single optical isomer. Ever since its first clinical application seven years ago, esomeprazole has attracted more and more attention due to relatively unique metabolism (compared to other PPIs), efficient and durable acid control, better safety and lower incidence of adverse reactions. In this article, we will review the clinical applications of esomeprazole in the treatment of gastroesophageal reflux disease (GERD), Helicobacter pylori infection, peptic ulcers, NSAID-related gastrointestinal disorders and upper gastrointestinal bleeding.

Treatment strategies for Zollinger-Ellison syndrome

BACKGROUND

Zollinger-Ellison syndrome (ZES) is a rare disorder caused by tumor secretion of the hormone gastrin, which results in gastric acid hypersecretion and secondarily complicated peptic ulcer and diarrhea. Until the development of H(2)-receptor antagonists and later proton pump inhibitors (PPIs), the disease was virulent, often associated with ulcer-related mortality, and the mainstay of treatment was total gastrectomy.

OBJECTIVE

To evaluate current approaches to diagnosis and therapy, focusing on the role of PPIs.

METHODS

An extensive literature search through PubMed using the search term 'Zollinger-Ellison syndrome' from 1964 to the present was performed. Primary articles were identified, and pertinent articles obtained from the reference lists were also examined.

RESULTS/CONCLUSIONS

The clinical manifestations of ZES are well described, but overlaps with other more common disorders delay diagnosis. The use of abdominal imaging with somatostatin receptor scintigraphy and endoscopic ultrasound has improved tumor staging. PPI therapy is remarkably effective in controlling gastric acid hypersecretion, thereby reducing morbidity and potential mortality of this syndrome. The dose of drug necessary to control symptoms is highly variable but, even when used in high doses for prolonged periods of time, the disease remained controlled with very few drug-related side effects.

Esomeprazole: a proton pump inhibitor

Proton pump inhibitors (PPIs) are the most potent inhibitors of gastric acid secretion available, and they are effective for treating all acid-related disorders. Esomeprazole is one of several most recent PPIs that became available to the market in 2001. Esomeprazole is indicated for the treatment of gastroesophageal reflux disease in adults and children, risk reduction of NSAIDs-associated gastric ulcer, Helicobacter pylori eradication and control of pathological hypersecretory conditions associated with Zollinger-Ellison syndrome. Esomeprazole is available in both oral and intravenous formulations. A number of studies have compared esomeprazole with other PPIs. While differences supporting esomeprazole have been reported, the magnitude of differences has been variable and of uncertain clinical importance. Cost plays a major role in prescribing patterns of PPIs.

Gastrointestinal neuroendocrine tumors: pancreatic endocrine tumors

Pancreatic endocrine tumors (PETs) have long fascinated clinicians and investigators despite their relative rarity. Their clinical presentation varies depending on whether the tumor is functional or not, and also according to the specific hormonal syndrome produced. Tumors may be sporadic or inherited, but little is known about their molecular pathology, especially the sporadic forms. Chromogranin A appears to be the most useful serum marker for diagnosis, staging, and monitoring. Initially, therapy should be directed at the hormonal syndrome because this has the major initial impact on the patient's health. Most PETs are relatively indolent but ultimately malignant, except for insulinomas, which predominantly are benign. Surgery is the only modality that offers the possibility of cure, although it generally is noncurative in patients with Zollinger-Ellison syndrome or nonfunctional PETs with multiple endocrine neoplasia-type 1. Preoperative staging of disease extent is necessary to determine the likelihood of complete resection although debulking surgery often is believed to be useful in patients with unresectable tumors. Once metastatic, biotherapy is usually the first modality used because it generally is well tolerated. Systemic or regional therapies generally are reserved until symptoms occur or tumor growth is rapid. Recently, a number of newer agents, as well as receptor-directed radiotherapy, are being evaluated for patients with advanced disease. This review addresses a number of recent advances regarding the molecular pathology, diagnosis, localization, and management of PETs including discussion of peptide-receptor radionuclide therapy and other novel antitumor approaches. We conclude with a discussion of future directions and unsettled problems in the field.

Neuroendocrine tumors of the gastro-entero-pancreatic system

Gastro-entero-pancreatic (GEP) neuroendocrine tumors (NETs) are rare neoplasms, although their prevalence has increased substantially over the past three decades. Moreover, there has been an increased clinical recognition and characterization of these neoplasms. They show extremely variable biological behavior and clinical course. Most NETs have endocrine function and secrete peptides and neuroamines that cause distinct clinical syndromes, including carcinoid syndrome; however, many are clinically silent until late presentation with mass effects. Investigation and management should be individualized for each patient, taking into account the likely natural history of the tumor and general health of the patient. Management strategies include surgery for cure or palliation, and a variety of other cytoreductive techniques, and medical treatment including chemotherapy, and biotherapy to control symptoms due to hormone release and tumor growth, with somatostatin analogues (SSAs) and alpha-interferon. New biological agents and somatostatin-tagged radionuclides are under investigation. Advances in the therapy and development of centers of excellence which coordinate multicenter studies, are needed to improve diagnosis, treatment and therefore survival of patients with GEP NETs.