Effect of omeprazole on changes in gastric and upper small intestine pH levels in patients with chronic pancreatitis

A Case of Severe Proton Pump Inhibitor-Induced Hypomagnesemia Refractory to Continuous Oral and Intravenous Magnesium Replenishment

Proton pump inhibitors (PPIs) are frequently used medications to treat a wide variety of gastrointestinal conditions. By irreversibly inhibiting the hydrogen-potassium ATPase pump, they remarkably reduce gastric acid secretion. However, chronic PPI intake can result in serious complications, including severe hypomagnesemia. The following case report presents a severe case of refractory PPI-induced hypomagnesemia (PPIH), resistant to continuous oral and intravenous magnesium replacement, in a 70-year-old male patient, with a long history of PPI use due to persistent epigastric pain. Upon each of the 10 admissions to the hospital, he presented with severe signs and symptoms of hypomagnesemia, such as nausea, muscle fasciculation, diffuse cramps, weakness, neuromuscular irritability, and ECG disturbances, including non-specific T-wave abnormalities. In fact, PPIH has been reported for the first time in 2006. It is believed that the excessive, chronic intake of PPIs can disturb the normal functioning of the transient receptor potential melastatin 6/7 (TRPM 6/7), which is the main pathway of active intestinal magnesium absorption, leading to hypomagnesemia. PPIH is typically characterized by stubborn resistance to oral and intravenous magnesium replenishment but usually resolves after PPI withdrawal. Hence, despite being among the safest and most commonly prescribed drugs, PPI intake should be closely monitored when prolonged usage is planned. Additionally, continuous follow-up and regular assessment of serum magnesium levels are crucial to avoid the occurrence of PPIH and to prevent its potentially deleterious complications, including life-threatening arrhythmias.

Prediction of Omeprazole Pharmacokinetics and its Inhibition on Gastric Acid Secretion in Humans Using Physiologically Based Pharmacokinetic-Pharmacodynamic Model Characterizing CYP2C19 Polymorphisms

PURPOSE

To develop a whole physiologically based pharmacokinetic-pharmacodynamic (PBPK-PD) model to describe the pharmacokinetics and anti-gastric acid secretion of omeprazole in CYP2C19 extensive metabolizers (EMs), intermediate metabolizers (IMs), poor metabolizers (PMs) and ultrarapid metabolizers (UMs) following oral or intravenous administration.

METHODS

A PBPK/PD model was built using Phoenix WinNolin software. Omeprazole was mainly metabolized by CYP2C19 and CYP3A4 and the CYP2C19 polymorphism was incorporated using in vitro data. We described the PD by using a turn-over model with parameter estimates from dogs and the effect of a meal on the acid secretion was also implemented. The model predictions were compared to 53 sets of clinical data.

RESULTS

Predictions of omeprazole plasma concentration (72.2%) and 24 h stomach pH after administration (85%) were within 0.5-2.0-fold of the observed values, indicating that the PBPK-PD model was successfully developed. Sensitivity analysis demonstrated that the contributions of the tested factors to the plasma concentration of omeprazole were Vmax,2C19 ≈ Papp > Vmax,3A4 > Kti, and contributions to its pharmacodynamic were Vmax,2C19 > kome > kms > Papp > Vmax,3A4. The simulations showed that while the initial omeprazole dose in UMs, EMs, and IMs increased 7.5-, 3- and 1.25-fold compared to those of PMs, the therapeutic effect was similar.

CONCLUSIONS

The successful establishment of this PBPK-PD model highlights that pharmacokinetic and pharmacodynamic profiles of drugs can be predicted using preclinical data. The PBPK-PD model also provided a feasible alternative to empirical guidance for the recommended doses of omeprazole.

Chronic pancreatitis and nutritional support

Malnutrition in patients with chronic pancreatitis is common, but its evaluation is often missed in clinical practice. Pancreatic exocrine insufficiency is the single most important cause of malnutrition; therefore, it needs to be screened for and treated appropriately. Specific diet regimens in patients suffering from chronic pancreatitis are rarely reported in the literature. Patients suffering from chronic pancreatitis have a higher demand for energy but a lower caloric intake secondary to pancreatic exocrine insufficiency, combined with the malabsorption of liposoluble vitamin and micronutrients, which needs be corrected by appropriate dietary counselling. Diabetes is frequently observed in chronic pancreatitis and classified as type 3c, which is characterized by low levels of both serum insulin and glucagon; therefore, there is a tendency towards hypoglycaemia in patients treated with insulin. Diabetes contributes to malnutrition in chronic pancreatitis. Strategies to treat exocrine and endocrine insufficiency are important to achieve better control of the disease.

Mechanisms of proton pump inhibitor-induced hypomagnesemia

Proton pump inhibitors (PPIs) reliably suppress gastric acid secretion and are therefore the first-line treatment for gastric acid-related disorders. Hypomagnesemia (serum magnesium [Mg²⁺ ] <0.7 mmol/L) is a commonly reported side effect of PPIs. Clinical reports demonstrate that urinary Mg²⁺ excretion is low in PPI users with hypomagnesemia, suggesting a compensatory mechanism by the kidney for malabsorption of Mg²⁺ in the intestines. However, the exact mechanism by which PPIs cause impaired Mg²⁺ absorption is still unknown. In this review, we show that current experimental evidence points toward reduced Mg²⁺ solubility in the intestinal lumen. Moreover, the absorption pathways in both the small intestine and the colon may be reduced by changes in the expression and activity of key transporter proteins. Additionally, the gut microbiome may contribute to the development of PPI-induced hypomagnesemia, as PPI use affects the composition of the gut microbiome. In this review, we argue that the increase of the luminal pH during PPI treatment may contribute to several of these mechanisms. Considering the fact that bacterial fermentation of dietary fibers results in luminal acidification, we propose that targeting the gut microbiome using dietary intervention might be a promising treatment strategy to restore hypomagnesemia in PPI users.

Is the remnant pancreas still working over a year after surgery in patients undergoing pancreaticoduodenectomy with reconstruction by pancreaticogastrostomy?

BACKGROUND

Pancreaticogastrostomy (PG) has been widely used as an alternative to pancreatojejunostomy (PJ) in patients undergoing pancreaticoduodenectomy (PD), but its long-term exocrine function remains unclear. The present study aimed to measure the secretion of pancreatic α-amylase (p-AMY) into the gastric cavity in patients who underwent PG reconstruction after PD over 1 year after surgery and to evaluate the relationship between gastric p-AMY level and clinically available indirect tests.

METHODS

Clinical records of 39 patients who underwent PG reconstruction after PD were reviewed. Pancreatic exocrine function was evaluated over 1 year after surgery using the following methods: 1) Measurement of p-AMY level in gastric fluids (gastric p-AMY level) during routine gastrointestinal endoscopy, 2) Qualitative faecal fat determination by Sudan III staining on faeces and 3) Pancreatic function diagnostic (PFD) test using oral administration of N-benzoyl-l-tyrosyl-p-aminobenzoic acid.

RESULTS

Gastric p-AMY level was detectable in 31 of 39 patients (79%), and 12 patients (30.8%) had steatorrhea over a year after surgery. Patients with steatorrhea had significantly lower gastric p-AMY level, larger diameter of remnant main pancreatic duct (MPD) and larger pancreatic duct to parenchymal thickness ratio than those without steatorrhea (84 IU/L vs 7979 IU/L, respectively; P < 0.001, 5.3 mm vs 3.2 mm, respectively; P = 0.001, and 0.38 vs 0.23, respectively; P = 0.007). Receiver operating characteristic analysis showed that the cut-off value of the diameter of the remnant MPD to predict steatorrhea was 3.5 mm (sensitivity, 92.3%; specificity, 70.4%). PFD test was not associated with any clinical data.

CONCLUSIONS

Pancreatic enzyme was detected in 79% of patients having PG reconstruction. Diameter of remnant MPD >3.5 mm and pancreatic parenchymal atrophy may be surrogate markers of postoperative exocrine insufficiency following PD.

Diagnostic and therapeutic recommendations for chronic pancreatitis. Recommendations of the Working Group of the Polish Society of Gastroenterology and the Polish Pancreas Club

This article describes the latest diagnostic and therapeutic recommendations in chronic pancreatitis, developed by the Working Group of the Polish Society of Gastroenterology and the Polish Pancreas Club. The recommendations refer to the diagnosis of chronic pancreatitis, autoimmune pancreatitis, conservative management, treatment of pain, and exocrine and endocrine pancreatic insufficiency, treatment of chronic pancreatitis by endoscopic and surgical methods, and oncological surveillance of chronic pancreatitis. This paper refers to the Polish recommendations published in 2011, which have been updated and supplemented. All recommendations were voted by experts of the Polish Society of Gastroenterology and the Polish Pancreas Club, who evaluated them each time on a five-degree scale, where I meant full acceptance, II – acceptance with some reservation, III – acceptance with serious reservation, IV – rejection with some reservation and V – full rejection. The results of the voting, together with a brief commentary, have been included with each recommendation put to the vote. In addition, the expert group assessed the value of clinical studies on which the statements are based, on a scale where A means high (based on meta-analyses and randomised clinical trials), B means medium (based on clinical trials and observational studies), and C means low (based mainly on expert opinion).

Evidence-based clinical practice guidelines for chronic pancreatitis 2015

Chronic pancreatitis is considered to be an irreversible progressive chronic inflammatory disease. The etiology and pathology of chronic pancreatitis are complex; therefore, it is important to correctly understand the stage and pathology and provide appropriate treatment accordingly. The newly revised Clinical Practice Guidelines of Chronic Pancreatitis 2015 consist of four chapters, i.e., diagnosis, staging, treatment, and prognosis, and includes a total of 65 clinical questions. These guidelines have aimed at providing certain directions and clinically practical contents for the management of chronic pancreatitis, preferentially adopting clinically useful articles. These revised guidelines also refer to early chronic pancreatitis based on the Criteria for the Diagnosis of Chronic Pancreatitis 2009. They include such items as health insurance coverage of high-titer lipase preparations and extracorporeal shock wave lithotripsy, new antidiabetic drugs, and the definition of and treatment approach to pancreatic pseudocyst. The accuracy of these guidelines has been improved by examining and adopting new evidence obtained after the publication of the first edition.

Zinc and gastrointestinal disease

This review is a current summary of the role that both zinc deficiency and zinc supplementation can play in the etiology and therapy of a wide range of gastrointestinal diseases. The recent literature describing zinc action on gastrointestinal epithelial tight junctions and epithelial barrier function is described. Zinc enhancement of gastrointestinal epithelial barrier function may figure prominently in its potential therapeutic action in several gastrointestinal diseases.

Pancreatic enzyme replacement therapy for pancreatic exocrine insufficiency in the 21st century

Restitution of normal fat absorption in exocrine pancreatic insufficiency remains an elusive goal. Although many patients achieve satisfactory clinical results with enzyme therapy, few experience normalization of fat absorption, and many, if not most, will require individualized therapy. Increasing the quantity of lipase administered rarely eliminates steatorrhea but increases the cost of therapy. Enteric coated enzyme microbead formulations tend to separate from nutrients in the stomach precluding coordinated emptying of enzymes and nutrients. Unprotected enzymes mix well and empty with nutrients but are inactivated at pH 4 or below. We describe approaches for improving the results of enzyme therapy including changing to, or adding, a different product, adding non-enteric coated enzymes, (e.g., giving unprotected enzymes at the start of the meal and acid-protected formulations later), use of antisecretory drugs and/or antacids, and changing the timing of enzyme administration. Because considerable lipid is emptied in the first postprandial hour, it is prudent to start therapy with enteric coated microbead prior to the meal so that some enzymes are available during that first hour. Patients with hyperacidity may benefit from adjuvant antisecretory therapy to reduce the duodenal acid load and possibly also sodium bicarbonate to prevent duodenal acidity. Comparative studies of clinical effectiveness of different formulations as well as the characteristics of dispersion, emptying, and dissolution of enteric-coated microspheres of different diameter and density are needed; many such studies have been completed but not yet made public. We discuss the history of pancreatic enzyme therapy and describe current use of modern preparations, approaches to overcoming unsatisfactory clinical responses, as well as studies needed to be able to provide reliably effective therapy.

Italian consensus guidelines for chronic pancreatitis

This paper gives practical guidelines for diagnosis and treatment of chronic pancreatitis. Statements have been elaborated by working teams of experts, by searching for and analysing the literature, and submitted to a consensus process by using a Delphi modified procedure. The statements report recommendations on clinical and nutritional approach, assessment of pancreatic function, treatment of exocrine pancreatic failure and of secondary diabetes, treatment of pain and prevention of painful relapses. Moreover, the role of endoscopy in approaching pancreatic pain, pancreatic stones, duct narrowing and dilation, and complications was considered. Recommendations for most appropriate use of various imaging techniques and of ultrasound endoscopy are reported. Finally, a group of recommendations are addressed to the surgical treatment, with definition of right indications, timing, most appropriate procedures and techniques in different clinical conditions and targets, and clinical and functional outcomes following surgery.

Treatment of alcoholic pancreatitis

Chronic pancreatitis is characterized by progressive and irreversible loss of pancreatic exocrine and endocrine function. The majority of cases in the Western world are related to alcohol consumption. Treatment of alcoholic chronic pancreatitis has been difficult, since the mechanisms of disease progression and the causes of pain are poorly understood. The conservative management of chronic pancreatitis focuses on (a) avoidance of precipitating factors such as alcohol and smoking; (b) treatment of pain, and (c) replacement of exocrine and endocrine function. There is a lack of good controlled, randomized treatment trials in alcoholic pancreatitis. However, there is good evidence that lifestyle changes, such as alcohol cessation, hamper progression of the disease. Conservative treatment of pain should be based on a stepwise approach; however, underlying causes such as pseudocysts may require endoscopic or surgical therapy. Treatment of exocrine insufficiency requires pancreatic enzyme supplementation and adjustment to several smaller meals per day, while treatment of endocrine insufficiency requires insulin treatment.

Pharmacokinetics of budesonide controlled-release capsules when taken with omeprazole

AIM

To investigate whether omeprazole affects the pharmacokinetics and systemic effects of budesonide controlled-release capsules when the two medications are taken together.

METHODS

Thirteen healthy volunteers were enrolled into a randomized, double-blind, placebo-controlled, cross-over study. Participants received omeprazole, 20 mg/day, or placebo every morning for 5 days, with three 3-mg budesonide controlled-release capsules being given with omeprazole or placebo on day 5. After a 12-day washout period, participants were switched from omeprazole to placebo, or vice versa, and the trial was repeated. Blood samples for pharmacokinetic evaluation and urine samples for cortisol assessments were collected before and after the budesonide doses.

RESULTS

No statistically significant differences were seen between omeprazole and placebo treatment with regard to any of the parameters analysed, including the maximum budesonide plasma concentration, time to concentration maximum, area under the concentration-time curve, mean residence time and urinary excretion of cortisol. Very few adverse events were reported during the trial, and the majority were of mild to moderate severity.

CONCLUSION

Omeprazole treatment does not affect the pharmacokinetics or systemic effects of budesonide controlled-release capsules when the two medications are taken simultaneously.