Omeprazole delays gastric emptying in healthy volunteers: an effect prevented by tegaserod

Physiologically-based pharmacokinetic modelling to predict intragastric rifabutin concentrations in the treatment of Helicobacter pylori infection

BACKGROUND

Sustained intragastric antibiotic exposure is important for Helicobacter pylori eradication, yet little is known about gastric pharmacology of commonly used H. pylori regimens. For rifabutin, differing intragastric concentrations based on dosing regimen may account for differences in reported eradication rates.

AIM

To compare intragastric rifabutin concentrations between low-dose rifabutin (50 mg three time daily; as in RHB-105) and generically dosed rifabutin 150 mg once daily, 150 mg twice daily, and 300 mg once daily using a validated Physiologically-based pharmacokinetic (PBPK) model.

METHODS

We obtained plasma pharmacokinetic data from the RHB-105 clinical development programs and used it to develop and validate a whole-body PBPK model using PK-SIM software. We modified the existing rifabutin model to include the impact of omeprazole on gastric pH and emptying time. Modelled intragastric rifabutin exposure was expressed as the time that each regimen maintained its concentration ≥MIC90 .

RESULTS

Rifabutin 50 mg three times daily achieved significantly longer times with intragastric concentration above MIC90 (22.3 ± 1.1 h) than 150 mg once daily (8.3 ± 1.7 h), 150 mg twice daily (16.3 ± 2.3 h), or 300 mg once daily (8.5 ± 1.9 h) while providing the lowest mean maximal plasma concentration and mean area under the plasma concentration-time curve of all regimens studied.

CONCLUSIONS

PBPK modelling showed rifabutin 50 mg three times daily had higher intragastric exposure times than 150 mg once daily or twice daily, or 300 mg once daily. This low-dose rifabutin regimen provides the highest potential for H. pylori eradication while minimising systemic rifabutin exposure.

Prediction of gastric pH-mediated drug exposure using physiologically-based pharmacokinetic modeling: A case study of itraconazole

Abnormal gastric acidity, including achlorhydria, can act as a significant source of variability in orally administered drugs especially with pH-sensitive solubility profiles, such as weak bases, potentially resulting in an undesirable therapeutic response. This study aimed to evaluate the utility of physiologically-based pharmacokinetic (PBPK) modeling in the prediction of gastric pH-mediated drug exposure by using itraconazole, a weak base, as a case. An itraconazole PBPK model was developed on the mechanistic basis of its absorption kinetics in a middle-out manner from a stepwise in vitro-in vivo extrapolation to in vivo refinement. Afterward, an independent prospective clinical study evaluating gastric pH and itraconazole pharmacokinetics (PKs) under normal gastric acidity and esomeprazole-induced gastric hypoacidity was conducted for model validation. Validation was performed by comparing the predicted data with the clinical observations, and the valid model was subsequently applied to predict PK changes under achlorhydria. The developed itraconazole PBPK model showed reasonable reproducibility for gastric pH-mediated exposure observed in the clinical investigation. Based on the model-based simulations, itraconazole exposure was expected to be decreased up to 65% under achlorhydria, and furthermore, gastric pH-mediated exposure could be mechanistically interpreted according to sequential variation in total solubility, dissolution, and absorption. This study suggested the utility of PBPK modeling in the prediction of gastric pH-mediated exposure, especially for drugs whose absorption is susceptible to gastric pH. Our findings will serve as a leading model for further mechanistic assessment of exposure depending on gastric pH for various drugs, ultimately contributing to personalized pharmacotherapy.

Postoperative Proton Pump Inhibitors are associated with a significantly higher rate of delayed gastric emptying after pancreatoduodenectomy

BACKGROUND

Proton pump inhibitors (PPIs) are effective in reducing marginal ulcers after pancreatoduodenectomy. However, their impact on perioperative complications has not been defined.

METHODS

We retrospectively analyzed the effect of postoperative PPIs on 90-day perioperative outcomes in all patients who underwent pancreatoduodenectomy at our institution from April 2017 to December 2020.

RESULTS

284 patients were included; 206 (72.5%) received perioperative PPIs, 78 (27.5%) did not. The two cohorts were similar in demographics and operative variables. Postoperatively, the PPI cohort had significantly higher rates of overall complications (74.3% vs. 53.8%) and delayed gastric emptying (28.6% vs. 11.5%), p < 0.05. However, no differences in infectious complications, postoperative pancreatic fistula, or anastomotic leaks were seen. On multivariate analysis, PPI was independently associated with a higher risk of overall complications (OR 2.46, CI 1.33-4.54) and delayed gastric emptying (OR 2.73, CI 1.26-5.91), p = 0.011. Four patients developed marginal ulcers within 90-days postoperatively; all were in the group who received PPIs.

CONCLUSION

Postoperative proton pump inhibitor use was associated with a significantly higher rate of overall complications and delayed gastric emptying after pancreatoduodenectomy.

Tegaserod: What's Old Is New Again

Irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) are common gastrointestinal disorders imposing considerable impact on the quality of life and well-being of affected individuals. A paucity of evidence-based treatment options exist for CIC and IBS-C sufferers. Tegaserod, a 5-HT₄ agonist, has a substantial body of preclinical and clinical study evidence to support its beneficial role in modulating sensorimotor function of the luminal gastrointestinal tract. Tegaserod was first approved for use by the U.S. Food and Drug Administration for the management of IBS-C and CIC in 2002 and 2004, respectively. Tegaserod enjoyed a successful uptake in the management of these disorders during its first several years of availability in the United States, but was later withdrawn from the market in 2007 over concerns related to adverse cardiovascular events. Since then, additional safety data has been generated, and following a resubmission and review by the Food and Drug Administration, in April 2019, tegaserod was once again approved for use in IBS-C under a more restricted labeling, confining use to women under 65 years of age without heart disease or additional cardiovascular risk factors. This review summarizes the regulatory journey of tegaserod and details the existing pharmacokinetic, physiologic, clinical, and safety data of tegaserod generated over the last 2 decades. The discussion also examines the future of tegaserod in the treatment of these constipation disorders, as well as its potential role in other related disorders of brain-gut interaction.

Food Residue During Esophagogastroduodenoscopy Is Commonly Encountered and Is Not Pathognomonic of Delayed Gastric Emptying

BACKGROUND AND AIMS

Retained gastric food (RGF) identified during esophagogastroduodenoscopy (EGD) is often attributed to gastroparesis. This retrospective study evaluated the prevalence of RGF, risk factors for RGF, and the association between RGF and delayed gastric emptying (GE).

METHODS

The prevalence and odds ratios for RGF in patients with structural foregut abnormalities or medical risk factors for delayed GE were determined from 85,116 EGDs performed between 2012 and 2018. The associations between RGF, delayed GE, and medical comorbidities were evaluated in 2991 patients without structural abnormalities who had undergone EGD and gastric emptying scintigraphy. The relationship between medication use and RGF was evaluated in 249 patients without structural or medical risk factors for RGF.

RESULTS

RGF was identified during 3% of EGDs. The odds of RGF were increased in patients with type 1 diabetes (12%, OR 1.7, P ≤ 0.001), type 2 diabetes (6%, OR 1.4, P ≤ 0.001), gastroparesis (14%, OR 4.8, P ≤ 0.001), amyloidosis (5%, OR 1.7, P ≤ 0.001), and structural foregut abnormalities (6%, OR 2.6, P ≤ 0.001). Overall, the PPV of RGF for delayed GE was 55%. However, the PPV varied from 32% in patients without risk factors to 79% in patients with type 1 diabetes. Opioids, cardiovascular medications, and acid suppressants were associated with RGF.

CONCLUSIONS

RGF is common during EGD. The PPV of RGF for delayed GE varies depending on underlying risk factors (type 1 diabetes, type 2 diabetes, gastroparesis, and amyloidosis). Acid suppressants or antacids, cardiovascular medications, and opioids are associated with RGF independent of delayed GE.

Administration of a standard dose of vonoprazan fumarate delays gastric emptying in Japanese healthy adults: a prospective clinical trial

BACKGROUND

There is no established view of how gastric acid suppression affects the time for gastric emptying. Vonoprazan fumarate shows potent and durable gastric acid inhibitory effects, but its effects on gastric emptying have not been studied widely. We investigated the effects of vonoprazan fumarate on gastric emptying and measured serum gastrin and plasma ghrelin levels in healthy adults.

METHODS

Ten participants were administered 10 mg vonoprazan fumarate daily for 14 days, then 20 mg vonoprazan fumarate daily for 14 days. The gastric emptying breath test was performed and serum gastrin levels were measured at baseline and after each medication administration period. The protocol was then repeated, with the gastric emptying breath test and serum gastrin and plasma desacyl-ghrelin levels measured at baseline and the end of the medication trial.

RESULTS

Mean serum gastrin levels increased in a dose-dependent manner [baseline: 104.7 ± 50.4, after 10 mg protocol: 328 ± 123.8, after 20 mg protocol: 555 ± 378.8 (pg/mL, mean ± standard deviation), p = 0.0008]. There was a significant difference between the gastric emptying breath test Tmax at baseline and just after the 20 mg protocol (baseline: 45.5 ± 15.3, after 20 mg protocol: 60.5 ± 19.6 min, p = 0.0418). Plasma desacyl-ghrelin levels increased significantly just after the 20 mg protocol compared to those at baseline [baseline: 222.3 ± 106.4, after 20 mg protocol: 366.2 ± 178.6 (fmol/mL), p = 0.0008].

CONCLUSIONS

In healthy adults, 14 days of vonoprazan fumarate administration at 20 mg/day delayed gastric emptying.

TRIAL REGISTRATION

This clinical trial was registered in the University hospital Medical Information Network Clinical Trial Registry (Trial No. UMIN000039199 and UMIN000042969).

Early effects of acotiamide or mosapride intake on gastric emptying: a randomized 3-way crossover study using the 13C breath test

The effects of acotiamide on gastrointestinal motility have not been sufficiently investigated. The aim of this study was to determine whether single preprandial acotiamide or mosapride intake might affect the gastric emptying rate using the ¹³C breath test. Here, 11 healthy volunteers participated in a randomized three-way crossover study. The subjects received acotiamide (100 mg) or mosapride (5 mg) or placebo before liquid test meal ingestion. Gastric emptying was estimated by determining following parameters: the time required for 50% emptying of the labeled meal (T1/2), lag time for 10% emptying of the labeled meal (Tlag), gastric emptying coefficient (GEC) and regression-estimated constants (β and κ). These parameters were calculated from a ¹³CO₂ breath excretion curve using conventional formulas. The acotiamide, mosapride and placebo conditions were compared, revealing that for gastric emptying rates (values expressed as median), T1/2 (87.83571 min vs 79.95057 min vs 88.74378 min, p = 0.1496), Tlag (46.36449 min vs 42.2897 min vs 47.08094 min, p = 0.4966), GEC (4.382027 vs 4.211441 vs 4.248495, p = 0.8858), β (1.917728 vs 1.757062 vs 1.869141, p = 0.4066) and κ (0.834051 vs 0.819820 vs 0.789523, p = 0.1225) did not significantly differ. In this study, acotiamide (100 mg) or mosapride (5 mg) had no effect on gastric emptying.

Gastrointestinal pharmacology: practical tips for the esophagologist

Gastroesophageal reflux disease (GERD) is primarily a motor disorder, and its pathogenesis is multifactorial. As a consequence, treatment should be able to address the underlying pathophysiology. Proton pump inhibitors (PPIs) are the mainstay of medical therapy for GERD, but these drugs only provide the control of symptoms and lesions without curing the disease. However, continuous acid suppression with PPIs is recommended for patients with Barrett's esophagus because of their potential chemopreventive effects. In addition to the antisecretory activity, these compounds display several pharmacological properties, often overlooked in clinical practice. PPIs can indeed affect gastric motility, exert a mucosal protective effect, and an antioxidant, anti-inflammatory, and antineoplastic activity, also protecting cancer cells from developing chemo- or radiotherapeutic resistance. Even in the third millennium, current pharmacologic approaches to address GERD are limited. Reflux inhibitors represent a promise unfulfilled, effective and safe prokinetics are lacking, and antidepressants, despite being effective in selected patients, give rise to adverse events in a large proportion of them. While waiting for new drug classes (like potassium-competitive acid blockers), reassessing old drugs (namely alginate-containing formulations), and paving the new avenue of esophageal mucosal protection are, at the present time, the only reliable alternatives to acid suppression.

Review article: treatment options for functional dyspepsia

BACKGROUND

Functional dyspepsia, consisting of epigastric pain syndrome and postprandial distress syndrome, is a prevalent functional gastrointestinal disorder. To date, only limited treatment options are available and conflicting results in terms of efficacy have been reported. Consequently, nonpharmacological treatment options are increasingly being explored for functional dyspepsia.

AIM

To provide an overview of current pharmacological and nonpharmacological treatment options for functional dyspepsia.

METHODS

A literature search was conducted on Pubmed and other sources to identify relevant studies.

RESULTS

Acid suppressive therapy reduced symptoms in 30%-70% of the patients, with higher benefit in epigastric pain syndrome and superior effectiveness for proton pump inhibitors compared to H₂ -antagonists. Prokinetic agents, primarily used to treat postprandial distress syndrome, showed variable efficiency: 59%-81% responder rate for dopamine receptor antagonists, 32%-91% for serotonin-4-receptor agonists and 31%-80% for muscarinic receptor antagonists. H Pylori eradication, recommended in infected patients, was effective in 24%-82%. Refractory symptoms are addressed with neuromodulators. However, their efficacy in functional dyspepsia remains incompletely elucidated, available data showing symptom reduction in 27%-71% of the patients. Regarding herbal agents, peppermint oil reduced symptoms in 66%-91%, rikkunshito in 29%-34% and iberogast in 20%-95%. Lastly, acupuncture, cognitive behavioural therapy and hypnotherapy may help to provide symptom control, but research on their efficacy remains sparse.

CONCLUSIONS

None of the available therapies is effective in the majority of patients without being associated with major side effects. Developing new treatment options is challenging due to the heterogeneity of functional dyspepsia, the lack of readily identified target mechanisms and the poor association between pathophysiological disturbances and symptoms.

Drug-drug interactions with imatinib: An observational study

Many patients treated with imatinib, used in cancer treatment, are using several other drugs that could interact with imatinib. Our aim was to study all the drug-drug interactions (DDIs) observed in patients treated with imatinib.We performed 2 observational studies, between the 1st January 2012 and the 31st August 2015 in the Midi-Pyrénées area (South Western France), using the French health insurance reimbursement database and then the French Pharmacovigilance Database (FPVD).A total of 544 patients received at least 1 reimbursement for imatinib. Among them, 486 (89.3%) had at least 1 drug that could potentially interact with imatinib. Paracetamol was the most frequent drug involved (77.4%). Proton pump inhibitors, dexamethasone and levothyroxine, were found in >10% of patients. In the FPVD, among a total of 25 reports of ADRs with imatinib recorded in the Midi-Pyrénées area, 10 (40%) had potential DDIs with imatinib. Imatinib was most frequently prescribed by hospital physicians and drugs interacting with imatinib, by general practitioners.Our study showed that at least 40% of the patients treated with imatinib were at risk of DDIs and that all prescribers must be cautious with DDIs in patients treated with imatinib. During imatinib treatment, we particularly recommend to limit the dose of paracetamol at 1300 mg per day, to avoid the use of dexamethasone, and to double the dose of levothyroxine.

Effect of esomeprazole, a proton pump inhibitor on the pharmacokinetics of sonidegib in healthy volunteers

AIMS

This study aimed to evaluate the impact of esomeprazole on the pharmacokinetics of sonidegib.

METHODS

This Phase I study evaluated the impact of the proton pump inhibitor (PPI) esomeprazole on the oral absorption and pharmacokinetics (PKs) of a single dose of sonidegib under fasted conditions. A total of 42 healthy subjects were enrolled to receive either sonidegib alone (200 mg single dose) or sonidegib in combination with esomeprazole (40 mg pre-treatment 5 days and combination were given on day 6). Primary PK parameters assessed in the study were area under the concentration-time curve (AUC) from 0-14 days and 0-7 days and maximum observed plasma concentration (Cmax ).

RESULTS

The plasma exposure (AUC0-14d, AUC0-7d and Cmax ) of a single 200 mg oral dose of sonidegib was decreased by 32-38% when sonidegib was co-administered with esomeprazole compared with sonidegib alone, with no apparent change in elimination slope and tmax . Baseline gastric pH was similar between the two arms.

CONCLUSIONS

These results suggest a modest reduction in the extent of sonidegib absorption by esomeprazole. There was no obvious metabolic drug-drug interaction between the two agents. Both sonidegib and esomeprazole were well tolerated in the study population.

The use of proton pump inhibitors decreases the risk of diabetes mellitus in patients with upper gastrointestinal disease: A population-based retrospective cohort study

OBJECTIVES

The aim of this study was to investigate the effects of proton pump inhibitors (PPIs) on the risk of diabetes mellitus (DM) among patients with upper gastrointestinal disease (UGID).

METHODS

This was a retrospective cohort study with a follow-up period of 5 years. We identified 388,098 patients who were diagnosed with UGID between 2000 and 2006 from the Longitudinal Health Insurance Database of the Taiwan National Health Insurance program. We used Cox proportional hazard ratio (HR) to compare the risk of DM between UGID patients received PPIs and those did not receive PPIs. HRs were adjusted for possible confounders, including age, sex, hypertension, gout and/or hyperuricemia, coronary artery disease, stroke, pancreatitis, hyperlipidemia, obesity, H2-blocker use, and clozapine or olanzapine use. The dose-related effects of PPIs on the risk of DM were evaluated according to the defined daily dose (DDD).

RESULTS

The adjusted HR was 0.80 (95% CI, 0.73-0.88) for the study group (UGID patients with PPIs) compared with comparison group I (UGID patients without PPIs). Among patients who used PPIs, those older than 60 years of age had a lower risk of DM (HR, 0.73; 95% CI, 0.63-0.83) than those younger than 40 years. Additionally, the effect of PPIs was significantly dose-dependent (P for trend <0.001). Patients with UGID who received >540 DDDs of PPIs exhibited the greatest reduction in the risk of DM.

CONCLUSIONS

Our results demonstrated a decreased risk of DM in UGID patients who used PPIs; the risk appeared to be significantly dose-dependent.

Therapy with proton pump inhibitors in patients with type 2 diabetes is independently associated with improved glycometabolic control

AIMS

Experimental data demonstrated that gastrin has incretin-like stimulating actions on β-cells, resulting in a promotion of glucose-induced insulin secretion. As proton pump inhibitors (PPIs) consistently increase plasma gastrin levels, a possible effect of this treatment on glucose-insulin homeostasis may be hypothesized. Therefore, the aim of this study was to evaluate the effect of chronic PPIs treatment on glycemic control in patients affected by type 2 diabetes.

METHODS

This is an observational, retrospective study. A total of 548 consecutive patients with type 2 diabetes (mean age ± SD: 67.1 ± 10.9 years, M/F: 309/239, diabetes duration: 12.4 ± 9.8 years) referring to our diabetes outpatient clinics were enrolled; among them, 45 %were treated with PPIs longer than 2 years for preventive/therapeutic purposes. Fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), serum lipids and transaminases were measured by standard laboratory methods. Major cardiovascular events and concomitant medications were recorded in all participants, and daily insulin requirement was calculated in insulin-treated subjects.

RESULTS

PPIs-treated patients had significantly lower HbA1c (7.1 ± 1.07 %-54.1 ± 12 vs 7.4 ± 1.4 %-57.4 ± 8 mmol/mol, p = 0.011) and FPG (127 ± 36.9 vs 147.6 ± 49.4 mg/dl, p < 0.001) levels than those untreated. These differences increased in patients under insulin therapy and in those with concomitant PPIs + GLP-1-based therapy. The multivariate regression analysis demonstrated that the association between chronic PPIs treatment and HbA1c was independent from possible confounders (p = 0.01).

CONCLUSIONS

PPIs treatment is associated with greater glycemic control in patients with type 2 diabetes, particularly in those on insulin- or GLP-1-based therapy. Our results suggest a role for PPIs in glucose-insulin homeostasis and may open a new scenario for diabetes therapy.

Suppression of contractile activity in the small intestine by indomethacin and omeprazole

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used to treat a number of conditions, and proton pump inhibitors (PPIs) are often used to prevent NSAID-induced gastric mucosal damage; however, the effects of NSAIDs on intestinal motility are poorly understood. The purpose of the present study is to determine the effects of a prototypical NSAID, indomethacin, either alone or in conjunction with the PPI omeprazole, on intestinal motility. Rats were randomly divided into four groups treated with vehicle, omeprazole, indomethacin, or a combination of indomethacin and omeprazole. Intestinal motility and transit were measured along with inflammatory mediators in the intestinal smooth muscle, markers of mucosal damage, and bacterial counts in the intestinal wall. Indomethacin, but not omeprazole, caused mucosal injury indicated by lower gut bleeding; however, both omeprazole and indomethacin suppressed contractile activity and frequency in the distal part of the small intestine. Cotreatment with omeprazole did not reduce indomethacin-induced intestinal bleeding. Furthermore, although indomethacin caused increased inflammation as indicated by increased edema development and inflammatory mediators, cotreatment with omeprazole did not reduce inflammation in the intestinal smooth muscle or prevent the increased bacterial count in the intestinal wall induced by indomethacin. We conclude that both NSAID and PPI treatment suppressed contractile activity in the distal regions of the small intestine. The suppression of intestinal contractility was associated with increased inflammation in both cases; however, indomethacin and omeprazole appear to affect intestinal motility by different mechanisms.

Pantoprazole may improve beta cell function and diabetes mellitus

BACKGROUND

Proton pump inhibitors induce hypergastrinemia by suppressing gastric acidity. Gastrin has incretin-like stimulating actions on beta cells. Proton pump inhibitors have been shown to decrease glycosylated hemoglobin.

AIM

We aimed to observe changes in beta cell function in diabetic and non-diabetic subjects given pantoprazole for an acid-related ailment.

METHODS

Seventy-nine male patients (38 non-diabetic and 41 type-2 diabetic receiving only metformin therapy) were followed for 12 weeks after pantoprazole 40 mg/day was given. Fasting plasma glucose, HbA1c, fasting insulin, Pancreatic B cell function (HOMA-B), proinsulin and c-peptide levels were measured before and after the treatment.

RESULTS

In non-diabetic patients (n = 38), FPG decreased, whereas c-peptide, log-HOMA-B, increased significantly (p = 0.002, p = 0.03, p = 0.042, respectively) after 12 weeks of pantoprazole administration. In type 2 diabetic patients, FPG, HbA1c and weight decreased, whereas log-HOMA-B, c-peptide and log-proinsulin levels increased significantly after pantoprazole treatment (p = 0.003, p = 0.007, p < 0.001; p < 0.001; p = 0.017, p = 0.05, respectively). After pantoprazole treatment, pancreatic B-cell function was correlated with c-peptide and insulin and inversely with FBG and HbA1c levels in the whole group (r = 0.37, p = 0.001; r = 0.60, p < 0.001, r = -0.29, p = 0.011 and r = -0.28, p = 0.013, respectively). After pantoprazole treatment, HbA1c was correlated with FBG (r = 0.75, p < 0.001) and inversely with only log-HOMA-B level (r = -0.28, p = 0.013).

CONCLUSIONS

Pantoprazole administration seems to correlate with increased beta cell function. Pantoprazole administration improves HbA1c, HOMA-B, c-peptide and proinsulin levels. Since beta cell loss plays a significant role in the pathogenesis of type 2 diabetes, PPI-based therapies may be useful in the treatment of diabetes.

Effects of the Addition of Mosapride to Gastroesophageal Reflux Disease Patients on Proton Pump Inhibitor: A Prospective Randomized, Double-blind Study

Background/Aims

Proton pump inhibitors (PPIs) which are the most effective agents for the treatment of gastroesophageal reflux disease (GERD), have been known to delay gastric emptying. Mosapride has been used as prokinetics by accelerating gastric emptying. We evaluated the efficacy of mosapride to prevent PPI-induced delayed gastric emptying in a prospective randomized, double-blind and placebo-controlled trial.

Methods

Thirty patients who were diagnosed as GERD and had normal gastric emptying were included in this study. PPI monotherapy group was treated with placebo drug in addition to pantoprazole and PPI plus mosapride group was treated with mosapride in addition to pantoprazole for 8 weeks. Gastric emptying scan and questionnaires about GERD and dyspeptic symptoms were assessed by scoring before and after treatment. To evaluate the changes of gastrointestinal endocrine hormones by PPI which are associated gastric acid secretion and gastric motility, fasting plasma gastrin and cholecystokinin were taken at weeks 0 and 8.

Results

Half gastric emptying time was increased (P = 0.023) in PPI monotherapy group, and there were no significant changes in PPI plus mosapride group. Plasma gastrin level increased in PPI monotherpay group (P = 0.028) and there were no significant changes in PPI plus mosapride group. Plasma cholecystokinin level was not changed after treatment in both groups. GERD symptoms were improved after treatment in both groups, and postprandial bloating and nausea were improved in PPI plus mosapride group.

Conclusions

Mosapride showed to be effective in preventing delayed gastric emptying and the increase in plasma gastrin level induced by PPI treatment, but did not show prominent clinical symptom improvements.

Contribution of ABCC4-mediated gastric transport to the absorption and efficacy of dasatinib

PURPOSE

Several oral multikinase inhibitors are known to interact in vitro with the human ATP-binding cassette transporter ABCC4 (MRP4), but the in vivo relevance of this interaction remains poorly understood. We hypothesized that host ABCC4 activity may influence the pharmacokinetic profile of dasatinib and subsequently affect its antitumor properties.

EXPERIMENTAL DESIGN

Transport of dasatinib was studied in cells transfected with human ABCC4 or the ortholog mouse transporter, Abcc4. Pharmacokinetic studies were done in wild-type and Abcc4-null mice. The influence of Abcc4 deficiency on dasatinib efficacy was evaluated in a model of Ph(+) acute lymphoblastic leukemia by injection of luciferase-positive, p185(BCR-ABL)-expressing Arf(-/-) pre-B cells.

RESULTS

Dasatinib accumulation was significantly changed in cells overexpressing ABCC4 or Abcc4 compared with control cells (P < 0.001). Deficiency of Abcc4 in vivo was associated with a 1.75-fold decrease in systemic exposure to oral dasatinib, but had no influence on the pharmacokinetics of intravenous dasatinib. Abcc4 was found to be highly expressed in the stomach, and dasatinib efflux from isolated mouse stomachs ex vivo was impaired by Abcc4 deficiency (P < 0.01), without any detectable changes in gastric pH. Abcc4-null mice receiving dasatinib had an increase in leukemic burden, based on bioluminescence imaging, and decreased overall survival compared with wild-type mice (P = 0.048).

CONCLUSIONS

This study suggests that Abcc4 in the stomach facilitates the oral absorption of dasatinib, and it possibly plays a similar role for other orally administered substrates, such as acetylsalicylic acid. This phenomenon also provides a mechanistic explanation for the malabsorption of certain drugs following gastric resection.

Improved diabetes control and pancreatic function in a type 2 diabetic after omeprazole administration

A 43-year-old man with type 2 diabetes, opposed to insulin use and poorly responsive to oral agents added sequentially over 6 years, was placed on 40 mg omeprazole twice daily. A linear decline in daily fasting blood glucose was observed over the first two-month treatment, and his hemoglobin A1c was reduced from 11.9% to 8.2%, then sustained at 8.1% after four months. Glucose, insulin, and C-peptide response to a 2-hour glucose tolerance test were consistently improved across this time period, and calculated beta-cell mass increased by 67%. We believe these responses are consistent with activation or neogenesis of pancreatic beta cells, possibly through a gastrin-mediated mechanism.

The effect of omeprazole on gastric myoelectrical activity and emptying

Omeprazole, a proton pump inhibitor, is widely used for the treatment of patients with peptic ulcer, gastroesophageal reflux disease and functional dyspepsia (FD), although some studies have demonstrated that omeprazole delays gastric emptying. The purpose of this study was to investigate the efficacy of omeprazole on gastric motility including gastric myoelectrical activity and gastric emptying. This study was performed on 12 healthy volunteers. Gastric motility was evaluated with cutaneously recorded electrogastrography (EGG) and gastric emptying of semi-solid meals using the (13)C-acetic acid breath test. EGG and gastric emptying were measured before and after treatment with 20 mg omeprazole orally for 7 days. In the fasting state, the percentage of EGG normogastria increased significantly compared to the baseline. No significant changes were observed in other EGG parameters including the percentage of tachygastria and bradygastria in both fasting and postprandial states, and the power ratios between both before and after ingestion of omeprazole. In addition, administrated omeprazole did not show any significant differences in the gastric emptying parameters such as the half emptying time. We conclude that administration of omeprazole did not affect gastric motility but improved gastric myoelectrical activity. These effects of omeprazole may be one of the mechanisms involved in its efficacy in relieving dyspeptic symptoms in FD patients.

Are proton pump inhibitors a new antidiabetic drug? A cross sectional study

AIM: To investigate the effect of proton pump inhibitors (PPIs) on glycemic control (HbA1c) in type 2 diabetic patients.

METHODS: A cross-sectional study of consecutive in-patients admitted to hospital in any department during the first semester of the year 2010 who had a recent HbA1c measurement. The study excluded those with a diagnosis of hyperglycemic decompensation, diabetic onset or pregnancy. It compared HbA1c levels of those taking PPIs and those not.

RESULTS: A total of 97 patients were recruited. The average HbA1C level was 7.0% ± 1.2%. Overall PPI consumption was 55.7%. HbA1c was significantly lower in individuals who took PPIs: -0.6%, 95% CI: -0.12 to -0.83. People who used PPIs with some type of insulin therapy had a HbA1c reduction by -0.8%, 95% CI: -0.12 to -1.48. For the rest of subgroup analysis based on the antidiabetic drug used, PPI consumption always exhibited lower HbA1c levels.

CONCLUSION: PPIs seems to be consistently associated with better glycemic control in type 2 diabetes. HbA1c reduction observed is similar to incretin-based therapies.

Barrett's esophagus: proton pump inhibitors and chemoprevention II

The following on proton pump inhibitors (PPIs) and chemoprevention in relation to Barrett's esophagus includes commentaries on 48-h pH monitoring, pH-impedence, bile acid testing, dyspepsia, long/short segment Barrett's esophagus, nonerosive reflux disease (NERD), functional heartburn, dual-release delivery PPIs, immediate-release PPIs, long-term PPI use, prokinetic agents, obesity, baclofen, nocturnal acid breakthrough, nonsteroidal anti-inflammatory drugs (NSAIDs), and new PPIs.

Insights into gastroesophageal reflux disease-associated dyspeptic symptoms

BACKGROUND & AIMS

Patients with GERD frequently report dyspeptic-like symptoms, including nausea, vomiting, early satiety, bloating, and belching. The purpose of this review was to define the epidemiology and underlying mechanisms for dyspeptic symptoms in GERD patients.

METHODS

We performed a systematic literature review to identify the prevalence of dyspeptic symptoms in GERD patients. We identified 2057 studies, and 37 studies (2%) met the entry criteria, including 17 articles describing the prevalence of dyspeptic symptoms in GERD subjects, 7 studies describing mechanistic evaluation of dyspeptic symptoms in GERD, 7 studies describing questionnaires used to measure dyspeptic symptoms, and 6 studies assessing the role of proton pump inhibitor therapy for dyspeptic symptoms associated with GERD. We used an evidence-based approach to assess the literature.

RESULTS

The median (± standard deviation) prevalence of GERD in 30,384 subjects from 8 studies conducted in Western countries was 30% ± 8% (range, 20%-40%). Dyspeptic symptoms were present in 38% ± 14% (range, 21%-63%) and were more frequent in patients with frequent GERD symptoms, compared with patients with intermittent or no GERD symptoms [Evidence B]. Patients with nonerosive disease had a higher prevalence of dyspeptic symptoms [Evidence B] in addition to a lower response to proton pump inhibitor therapy [Evidence A], compared with patients with erosive esophagitis. Epigastic pain, belching, bloating, and early satiety demonstrated improvement on PPI therapy [Evidence A], compared with symptoms of nausea and vomiting that did not improve [Evidence A]. Patients with dyspepsia were at risk for a subsequent new diagnosis of GERD [Evidence B]. Dyspeptic symptoms contributed significantly to the decrement in health-related quality of life associated with GERD.

CONCLUSIONS

Dyspeptic symptoms are common in GERD patients and impact health-related quality of life.

Effects of proton pump inhibitors on gastric emptying: a systematic review

The proton pump inhibitor (PPI) is widely used for the treatment of gastroesophageal reflux disease, peptic ulcer diseases, and functional dyspepsia. The pathogenesis of these acid-related and/or functional upper gastrointestinal disorders is potentially associated with abnormal gastric emptying. To date, variable effects of PPIs on gastric emptying have been reported. Therefore, it is relevant to gather and analyze published information on this topic. A systematic literature search has been performed, showing that the delaying effect of PPIs on gastric emptying of solid meals is consistent, whereas the effect of PPIs on the emptying of liquids is inconsistent. The underlying mechanisms whereby PPIs may affect gastric emptying have been discussed, most of which still remain hypothetic. Gastric emptying of solids involves a process of peptic hydrolysis. PPIs impair the hydrolytic digestion by inhibiting acid-dependent peptic activity, thereby delaying the solid emptying. Gastric emptying of liquids largely depends on volume and energy density of intragastric contents. PPIs variably modify the volume and the energy density by reducing gastric fluid secretion, thereby modifying the liquid emptying in an unpredictable manner. Hypergastrinemia has been considered to delay gastric emptying, but it seems of minor importance in the regulation of gastric emptying during PPI use. The delayed emptying of solids due to PPI therapy may have clinical implications in the management of gastroesophageal reflux disease, functional dyspepsia, as well as diabetes.

Long-term treatment with proton pump inhibitor is associated with undesired weight gain

AIM: To examine the effects of long-term proton pump inhibitor (PPI) therapy on body weight (BW) and body mass index (BMI) in patients with gastroesophageal reflux disease (GERD).

METHODS: The subjects were 52 patients with GERD and 58 sex- and age-matched healthy controls. GERD patients were treated with PPI for a mean of 2.2 years (range, 0.8-5.7 years), and also advised on lifestyle modifications (e.g. selective diet, weight management). BW, BMI and other parameters were measured at baseline and end of study.

RESULTS: Twenty-four GERD patients were treated daily with 10 mg omeprazole, 12 with 20 mg omeprazole, 8 with 10 mg rabeprazole, 5 with 15 mg lansoprazole, and 3 patients with 30 mg lansoprazole. At baseline, there were no differences in BW and BMI between reflux patients and controls. Patients with GERD showed increases in BW (baseline: 56.4 ± 10.4 kg, end: 58.6 ± 10.8 kg, mean ± SD, P < 0.0001) and BMI (baseline: 23.1 ± 3.1 kg/m², end: 24.0 ± 3.1 kg/m², P < 0.001), but no such changes were noted in the control group. Mean BW increased by 3.5 kg (6.2% of baseline) in 37 (71%) reflux patients but decreased in only 6 (12%) patients during treatment.

CONCLUSION: Long-term PPI treatment was associated with BW gain in patients with GERD. Reflux patients receiving PPI should be encouraged to manage BW through lifestyle modifications.

Effect of a proton pump inhibitor on the pharmacokinetics of imatinib

AIMS

Imatinib mesylate (Gleevec/Glivec), which has revolutionized the treatment of chronic myeloid leukemias (CML) and gastrointestinal stromal tumours (GIST), has been reported to cause gastric upset. Consequently, proton pump inhibitors (PPI) are frequently co-administered with imatinib. Because PPI can elevate gastric pH and delay gastric emptying or antagonize ATP-binding-cassette transporters, they could influence imatinib absorption and pharmacokinetics. We aimed to evaluate whether use of omeprazole has a significant effect on imatinib pharmacokinetics.

METHODS

Twelve healthy subjects were enrolled in a two-period, open-label, single-institution, randomized cross-over, fixed-schedule study. In one period, each subject received 400 mg imatinib orally. In the other period, 40 mg omeprazole (Prilosec) was administered orally for 5 days, and on day 5 it was administered 15 min before 400 mg imatinib. Plasma concentrations of imatinib and its active N-desmethyl metabolite CGP74588 were assayed by LC-MS, and data were analyzed non-compartmentally.

RESULTS

PPI administration did not significantly affect the imatinib area under the plasma concentration vs time curve (AUC) (34.1 microg ml(-1) h alone vs 33.1 microg ml(-1) h with omeprazole, P= 0.64; 80% power), maximum plasma concentration (C(max)) (2.04 microg ml(-1) alone vs 2.02 microg ml(-1) with omeprazole, P= 0.97), or half-life (13.4 h alone vs 14.1 h with omeprazole, P= 0.13).

CONCLUSIONS

Our results indicate that the use of omeprazole does not significantly affect the pharmacokinetics of imatinib, as opposed to, for example, dasatinib where PPI decreased AUC and C(max) two-fold.

A pharmacokinetic study of etravirine (TMC125) co-administered with ranitidine and omeprazole in HIV-negative volunteers

AIMS

Etravirine is a next-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) with activity against wild-type and NNRTI-resistant HIV. Proton pump inhibitors and H(2)-antagonists are frequently used in the HIV-negative-infected population, and drug-drug interactions have been described with other antiretrovirals. This study evaluated the effect of steady-state omeprazole and ranitidine on the pharmacokinetics of a single dose of etravirine.

METHODS

In an open-label, randomized, one-way, three-period crossover trial, HIV-negative volunteers randomly received a single dose of 100 mg etravirine alone (treatment A); 11 days of 150 mg ranitidine b.i.d. (treatment B); and 11 days of 40 mg omeprazole q.d. (treatment C). A single dose of 100 mg etravirine was co-administered on day 8 of sessions 2 and 3. Each session was separated by a 14-day wash-out.

RESULTS

Nineteen volunteers (seven female) participated. When a single dose of etravirine was administered in the presence of steady-state ranitidine, etravirine least squares means ratios (90% confidence interval) for AUC(last) and C(max) were 0.86 (0.76, 0.97) and 0.94 (0.75, 1.17), respectively, compared with administration of etravirine alone. When administered with steady-state omeprazole, these values were 1.41 (1.22, 1.62) and 1.17 (0.96, 1.43), respectively. Co-administration of a single dose of etravirine and ranitidine or omeprazole was generally safe and well tolerated.

CONCLUSIONS

Ranitidine slightly decreased etravirine exposure, whereas omeprazole increased it by approximately 41%. The increased exposure of etravirine when co-administered with omeprazole is attributed to CYP2C19 inhibition. Considering the favourable safety profile of etravirine, these changes are not clinically relevant. Etravirine can be co-administered with proton pump inhibitors and H(2) antagonists without dose adjustments.

Advances in roles of prokinetic agents in the treatment of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is characterized by the reflux of gastric content into esophagus with or without histological changes. Pathogenesis of GERD is lower esophageal sphincter (LES) dysfunction, abnormal clearing capacity of refluxed materials, delayed gastric emptying and abnormal resistance of esophageal mucosa to gastric acid, but the primary upper gastrointestinal motility dysfunction is regarded as the most important factor in general. Therefore, prokinetic agents which can restore gastric motility with increasing of LES and esophageal motility have been developed and used frequently in the treatment of GERD. There are several prokinetic agents such as metoclopramide, domperidone, cisapride and mosapride that facilitate acetylcholine release from the enteric cholinergic neurons through a selective 5-HT₄ receptor agonistic action. It is considered that prokinetic agents have the same effect as H2 blocker in the treatment of patients with mild GERD. Additionally, it was reported that a combination therapy with prokinetic agents and proton pump inhibitors (PPI) or H2 receptor antagonists (H2RAs) is more effective than monotherapy in patients with severe GERD. This article reviews the recent advances in the role of prokinetic agents in the treatment of gastroesophageal reflux disease.

Nizatidine and gastric emptying in functional dyspepsia

In clinical practice, H2-receptor antagonists, including nizatidine, in addition to their use in the treatment of peptic ulcer and gastroesophageal reflux, are also useful in alleviating dyspeptic symptoms. Patients with functional dyspepsia show a tendency to delayed gastric emptying. Results of preliminary studies have demonstrated that nizatidine has a prokinetic effect due to its cholinergic properties. The aim of this study was to evaluate the effect of nizatidine on gastric emptying in patients with functional dyspepsia. Sixteen patients with dyspeptic symptoms referred for gastroscopy by primary care physicians were enrolled in this randomized, placebo-controlled, double-blind cross-over study. They received nizatidine 150 mg twice daily or placebo for 2 months. After a 1-month washout period, the 2-month treatment was repeated, with these patients acting as their own controls. Gastric emptying was measured by scintigraphy, and dyspeptic symptoms and quality of life were evaluated at the end of both treatment periods. Gastric emptying of solids during nizatidine therapy was prolonged (T1/2 110.1 +/- 76.7 vs. 65.6 +/- 23.2 min, P = 0.03), but nizatidine had no effect on gastric emptying of liquids. Nizatidine improved the symptom scores and seven of eight aspects of quality of life - but not significantly. In conclusion, nizatidine decreases the gastric emptying rate of solids without having a significant effect on symptoms or quality of life in functional dyspepsia.

Rabeprazole delays gastric emptying of a nutrient liquid

BACKGROUND

It is generally considered that gastric acid suppression delays gastric emptying of solid meals because gastric hypoacidity impairs peptic digestion and antral triturition. Rabeprazole is one of the most potent acid suppressants. We conducted this cross-over study to investigate if rabeprazole delays gastric emptying of liquid nutrients, for which peptic digestion is unnecessary.

METHODS

On two randomized occasions, 13 healthy male volunteers underwent the (13)C-acetate breath test following ingestion of a 300 kcal-liquid meal. On one occasion, they had received 20 mg rabeprazole for the preceding 2 days and 1 h before the test. On another, they took no pretreatment. Based on 4 h breath samples, the half (13)CO(2) excretion time (t(1/2b)) and the time of maximal excretion (t(max)) were calculated as overall measures of gastric emptying. In addition, time profiles of gastric emptying were generated using the Wagner-Nelson analytical method, which creates the gastric emptying curve as accurately as the scintigraphy.

RESULTS

Rabeprazole significantly prolonged t(max) but unchanged t(1/2b). The gastric emptying profiles showed that rabeprazole evoked a segmental slowing of gastric emptying during 0.5-1.25 h of post-meal ingestion.

CONCLUSIONS

Rabeprazole suppresses gastric emptying of a liquid nutrient 0.5 h after meal ingestion. We have speculated that: (i) rabeprazole delays gastric emptying via a mechanism other than acid-pepsin maldigestion; and (ii) rabeprazole may intensify the post-gastric feedback regulation system (>0.5 h of post-meal).

Effect of a proton pump inhibitor on postprandial gastric volume, emptying and symptoms in healthy human subjects: a pilot study

BACKGROUND

In consensus guidelines, proton pump inhibitors (PPIs) are recommended for the treatment of functional dyspepsia. It is unclear whether PPIs change gastric volume or emptying.

AIM

To assess the effect of a PPI, rabeprazole, on gastric volume and emptying and postprandial symptoms.

METHODS

In a double-blind, parallel-group placebo-controlled trial, 13 healthy participants were randomized to rabeprazole, 20 mg b.d., or placebo. On day 3, fasting gastric volume was measured using intravenous (99m)Tc-pertechnate and single photon emission computed tomography (SPECT). After the last dose of study medication, an (111)In-chloride egg meal (300 kcal) was ingested, and postprandial gastric volume and emptying were measured by SPECT. Symptom ratings using a visual analogue scale (fullness, nausea, bloating, abdominal pain, aggregate score) were obtained at baseline and 15, 30, 45, 60 and 75 min postprandially. Group comparisons were performed using Mann-Whitney rank sum test.

RESULTS

There were no statistically significant differences in gastric volume or emptying in the two groups. However, there was a borderline increase in gastric volume with rabeprazole compared with placebo. Rabeprazole treatment reduced aggregate postprandial symptoms, particularly fullness, 30 min after the meal (P = 0.01).

CONCLUSIONS

In healthy participants, rabeprazole, 20 mg b.d., did not significantly change gastric emptying, but reduced symptoms and had a borderline effect on gastric volume postprandially. The mechanism of reduced postprandial symptoms with a PPI requires further study.

Effect of omeprazole on the pharmacokinetics of saquinavir-500 mg formulation with ritonavir in healthy male and female volunteers

INTRODUCTION

Recent studies have described reduced absorption of certain protease inhibitors when administered with agents known to increase gastric pH. No clinically significant interactions between saquinavir absorption and gastric pH have previously been shown. We evaluated the effect of omeprazole, a proton-pump-inhibitor, on the pharmacokinetics of the recently developed saquinavir-500 mg formulation co-administered with ritonavir.

METHODS

Eighteen healthy subjects (n = 6 women and 12 men) received 1000/100 mg saquinavir/ritonavir twice daily in an open-label study for 15 days. On days 11-15, subjects were administered omeprazole 40 mg daily with the morning dose. Serial plasma samples were collected for 12-h pharmacokinetic profiles of saquinavir and ritonavir on days 10 and 15 and safety analysis on days 1, 4, 10, 15 and 29.

RESULTS

The geometric mean and 95% confidence interval (CI), for the area under time-concentration curve (AUC; ng h/ml), trough plasma concentration (C trough; ng/ml) and maximum observed plasma concentration (Cmax; ng/ml) of saquinavir were 20599 (14396-29360) and 37511 (28733-48970); 737 (482-1127) and 1521 (1039-2227); 3227 (2370-4393) and 5611 (4507-7710) on days 10 and 15, respectively, with geometric mean ratios of 1.82, 2.06 and 1.75. No significant changes were observed in saquinavir elimination half life, ritonavir pharmacokinetic parameters or in safety laboratory tests. No unexpected adverse events attributed to study medication were noted.

CONCLUSIONS

In the presence of omeprazole, total saquinavir plasma exposure is significantly increased (82% increase in AUC). The mechanism of this interaction requires elucidation. Despite the significant increase in saquinavir exposure, no short term toxicities were observed.

Review article: physiologic and clinical effects of proton pump inhibitors on non-acidic and acidic gastro-oesophageal reflux

The control of oesophageal acid exposure through gastric acid inhibition, as the basis for gastro-oesophageal reflux disease (GERD) treatment, arose from the apparent pH dependency of erosive oesophagitis and relationship to GERD symptoms. The current perception is that reflux disease is an entirely acid-mediated condition, and antisecretory therapies, particularly proton pump inhibitors, are the treatment of choice for patients with erosive and non-erosive reflux disease. A positive patient response to an empiric trial of proton pump inhibitor (PPI) therapy, or the 'PPI test', is commonly suggested as a method of GERD diagnosis. Recent studies have modified our understanding of the relationship between oesophageal acid exposure and GERD pathology, manifestations and symptoms. Whereas the use of PPIs to reduce oesophageal acid exposure in patients with erosions is associated with increased healing rates, non-erosive reflux disease patients are less likely to have an abnormal oesophageal pH profile. Patterns of oesophageal acid exposure, particularly nocturnal oesophageal acid exposure, have been linked to increased disease severity. Non-acidic reflux and the effect of PPIs on this parameter, including bile reflux and the toxicity of bile acids, may also be an important factor in GERD. This article explores some of these assumptions, practices and relationships, including: the association between oesophageal acid exposure and erosive and non-erosive gastro-oesophageal reflux disease; the effect of PPIs on oesophageal acid exposure in erosive oesophagitis patients; the influence of nocturnal acid secretion in GERD and the use of PPIs to control this parameter; the relevance of the PPI test for reflux disease diagnosis; and PPI influence on non-acidic reflux.

Tegaserod in the treatment of irritable bowel syndrome with constipation

Tegaserod, a novel serotonin receptor agonist, has gained acceptance and widespread use for the treatment of women with irritable bowel syndrome and constipation. Development of this therapy evolved from the emerging role of serotonin in gastrointestinal motor, secretory and sensory functions. The efficacy and safety of tegaserod has been well established in women suffering from irritable bowel syndrome with constipation. Large, randomized, double-blind, placebo-controlled trials involving more than 3500 predominantly female patients with irritable bowel syndrome and constipation have demonstrated the superiority of tegaserod over placebo in improving global and individual symptoms. The most common side effects of tegaserod in clinical trials were diarrhea and headache. Recent data suggest that retreatment with tegaserod after a drug holiday is efficacious, opening the door to the possibility of intermittent therapy for patients with irritable bowel syndrome and constipation. Areas in need of further investigation include the role of tegaserod in the treatment of pain and bloating in irritable bowel syndrome, whether tegaserod has a role in male patients, the long-term efficacy of tegaserod, whether tolerance develops in a subset of patients with extended therapy and whether tegaserod is beneficial for the treatment of other functional gastrointestinal disorders.