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For decades the rationale for treatment of gastro-oesophageal reflux disease (GORD) with acid suppressors, such as proton pump inhibitors (PPIs), was that symptoms were attributable to reflux of acidic stomach contents into the oesophagus. However, recent advances in the understanding of how brain–gut interactions can modulate the perception of visceral stimuli have complicated the concept of GORD.1 It is increasingly evident that altered perception of reflux is an important underlying cause of symptoms.2 A number of syndromes related to visceral hypersensitivity and central nervous system dysregulation are now recognised as ‘functional’ gastrointestinal (GI) disorders, potentially localised to the oesophagus,3 bowel, stomach, duodenum, anorectum, gallbladder, or multiple GI sites in the same patient. These functional syndromes are common; an internet-based health survey of almost 6000 adults in the US, Canada, and the UK found that 35% had symptoms compatible with some functional GI disorder and 7% met diagnostic criteria for a functional oesophageal disorder.4 This could potentially account for a large fraction of the adults with weekly reflux symptoms in population-based assessments (global prevalence ∼13%).5 However, it being impractical to investigate all of these patients, the recognition of altered perception as a major determinant of reflux symptoms has had little impact on management in general practice. To provide guidance for the management of uninvestigated reflux symptoms in primary care, a series of sponsored (Reckitt Benckiser Healthcare Ltd, UK) workshops were held among gastroenterologists, GI surgeons, and GPs. The objective was to translate recent research findings into clinical practice strategies. Epidemiological data suggest that the prevalence of GORD has increased considerably since the mid-1990s. However, wider public awareness of the link between reflux symptoms and oesophageal cancer6 has likely contributed to the increased presentation of symptomatic patients in primary care. Additionally, the more we understand the …

Findings Between June 16, 2014, and July 28, 2017, 122 patients were eligible for screening and a total of 95 patients were randomly assigned to the infliximab-continued group (n=48) or the infliximab-discontinued group (n=47). 92 patients (n=46 for both groups) were included in the full analysis set. 37 (80.4% [95% CI 66.1-90.6]) of 46 patients in the infliximab-continued group and 25 (54.3% [39.0-69.1]) of 46 patients in the infliximab-discontinued group were in remission at week 48. The between-group difference was 26.1% (95% CI 7.7-44.5; p=0.0076) before adjustment and 27.3% (95% CI 8.0-44.1; p=0.0059) after adjustment for stratification factors. Eight (17%) of 48 patients in the infliximab-continued group and six (13%) of 47 in the infliximab-discontinued group developed adverse events (between-group difference 3.9% [95% CI -10.3 to 18.1]; p=0.59). In the infliximab-continued group, one patient had an infusion reaction and two patients had psoriatic skin lesions. Eight (66.7%, 95% CI 34.9-90.1) of the 12 patients in the infliximab-discontinuation group who were re-treated with infliximab after relapsing were in remission within 8 weeks of re-treatment; none had infusion reactions.Background Anti-tumour necrosis factor (TNF) agents are the mainstay of long-term treatment for refractory ulcerative colitis. However, long-term use of anti-TNF therapy might lead to an increased risk of malignancy or infection. To date, no randomised controlled trial has evaluated whether anti-TNF agents can be safely discontinued in patients with ulcerative colitis in remission. We therefore aimed to compare outcomes in these patients who continued infliximab with those who discontinued infliximab.Methods We did a multicentre, open-label randomised controlled trial at 24 specialist centres in Japan. We enrolled patients with ulcerative colitis who were in remission, had been treated with intravenous infliximab (5 mg/kg) every 8 weeks, and had started infliximab at least 14 weeks before study enrolment. No restrictions regarding age and comorbidities were used to exclude participation. Patients who were confirmed to be in remission for more than 6 months, to be corticosteroid-free, and to have a Mayo Endoscopic Subscore (MES) of 0 or 1 were centrally randomised. An independent organisation randomly assigned patients (1:1) into either the infliximab-continued group or infliximab-discontinued group, using a computer-generated stratified randomisation procedure. The stratified factors were the use of immunomodulators (yes or no) and MES (0 or 1). Neither patients nor health-care providers were masked to the randomisation. The primary endpoint was the remission rate at week 48 in the full analysis set, which was based on the intention-to-treat principle and excluded participants with no efficacy data after randomisation. This study was registered with the University Hospital Medical Information Network Center Trials registry, UMIN000012092. Findings Between June 16, 2014, and July 28, 2017, 122 patients were eligible for screening and a total of 95 patients were randomly assigned to the infliximab-continued group (n=48) or the infliximab-discontinued group (n=47). 92 patients (n=46 for both groups) were included in the full analysis set. 37 (80.4% [95% CI 66.1-90.6]) of 46 patients in the infliximab-continued group and 25 (54.3% [39.0-69.1]) of 46 patients in the infliximab-discontinued group were in remission at week 48. The between-group difference was 26.1% (95% CI 7.7-44.5; p=0.0076) before adjustment and 27.3% (95% CI 8.0-44.1; p=0.0059) after adjustment for stratification factors. Eight (17%) of 48 patients in the infliximab-continued group and six (13%) of 47 in the infliximab-discontinued group developed adverse events (between-group difference 3.9% [95% CI & minus;10.3 to 18.1]; p=0.59). In the infliximab-continued group, one patient had an infusion reaction and two patients had psoriatic skin lesions. Eight (66.7%, 95% CI 34.9-90.1) of the 12 patients in the infliximab-discontinuation group who were re-treated with infliximab after relapsing were in remission within 8 weeks of re-treatment; none had infusion reactions.Interpretation Maintenance of remission was significantly more common in patients who continued infliximab than in those who discontinued. Discontinuing infliximab should therefore be discussed with caution, taking both risk of relapse and efficacy of re-treatment into account.Funding Mitsubishi Tanabe Pharma Corporation and the Intractable Disease Project of the Ministry of Health, Labour and Welfare of Japan.Copyright (c) 2021 Elsevier Ltd. All rights reserved.

BACKGROUND Chronic constipation is a prevalent disorder that affects quality of life of patients and consumes resources in healthcare systems worldwide. In clinical practice, it is still considered a challenge as clinicians frequently are unsure as to which treatments to use and when. Over a decade ago, a Neurogastroenterology and Motility journal supplement devoted to the investigation and management of constipation was published (Neurogastroenterol Motil 2009;21(Suppl 2):1). In October 2018, the 3rd London Masterclass, entitled "Contemporary management of constipation" was held. The faculty members of this symposium were invited to write two reviews to present a collective synthesis of talks presented and discussions held during this meeting. The first review addresses epidemiology, diagnosis, clinical associations, pathophysiology, and investigation. PURPOSE The present is the second of these reviews, providing contemporary perspectives and clinical challenges regarding behavioral, conservative, medical, and surgical treatments for patients presenting with constipation. It includes a management algorithm to guide clinical practice.

BACKGROUND: Chronic constipation is a prevalent disorder that affects patients' quality of life and consumes resources in healthcare systems worldwide. In clinical practice, it is still considered a challenge as clinicians frequently are unsure as to which treatments to use and when. Over a decade ago, a Neurogastroenterology & Motility journal supplement devoted to the investigation and management of constipation was published (2009; 21 (Suppl.2)). This included seven articles, disseminating all themes covered during a preceding 2-day meeting held in London, entitled “Current perspectives in chronic constipation: a scientific and clinical symposium.” In October 2018, the 3rd London Masterclass, entitled “Contemporary management of constipation” was held, again over 2 days. All faculty members were invited to author two new review articles, which represent a collective synthesis of talks presented and discussions held during this meeting. PURPOSE: This article represents the first of these reviews, addressing epidemiology, diagnosis, clinical associations, pathophysiology, and investigation. Clearly, not all aspects of the condition can be covered in adequate detail; hence, there is a focus on particular “hot topics” and themes that are of contemporary interest. The second review addresses management of chronic constipation, covering behavioral, conservative, medical, and surgical therapies.

BACKGROUND AND AIMS: The symptom-based diagnostic criteria for irritable bowel syndrome (IBS) have recently been revised in the Rome IV consensus. On the other hand, with rising public awareness of IBS, self-diagnosis and self-management is also increasing. We compared the prevalence and impact of Rome IV-based IBS vs self-diagnosed IBS in the general population. METHODS: An internet panel filled out an online survey on bowel symptoms and their impact on health care utilization and daily activities. RESULTS: A representative internet panel of 1012 individuals completed the online survey. Bowel symptoms were present in 68.6% of the population. Of these, 21% consulted a physician for these symptoms in the last year and 42% earlier. Rome IV IBS criteria were fulfilled by 5.5%, and these were younger and more likely to be female. In this subset, 37% had consulted a physician for IBS symptoms in the preceding year and 29% had done so earlier. A colonoscopy had been performed in 22%. Based on a brief description, 17.6% of the population self-identified as suffering from IBS (p

The simultaneous intake of food and drugs can have a strong impact on drug release, absorption, distribution, metabolism and/or elimination and consequently, on the efficacy and safety of pharmacotherapy. As such, food-drug interactions are one of the main challenges in oral drug administration. Whereas pharmacokinetic (PK) food-drug interactions can have a variety of causes, pharmacodynamic (PD) food-drug interactions occur due to specific pharmacological interactions between a drug and particular drinks or food. In recent years, extensive efforts were made to elucidate the mechanisms that drive pharmacokinetic food-drug interactions. Their occurrence depends mainly on the properties of the drug substance, the formulation and a multitude of physiological factors. Every intake of food or drink changes the physiological conditions in the human gastrointestinal tract. Therefore, a precise understanding of how different foods and drinks affect the processes of drug absorption, distribution, metabolism and/or elimination as well as formulation performance is important in order to be able to predict and avoid such interactions. Furthermore, it must be considered that beverages such as milk, grapefruit juice and alcohol can also lead to specific food-drug interactions. In this regard, the growing use of food supplements and functional food requires urgent attention in oral pharmacotherapy. Recently, a new consortium in Understanding Gastrointestinal Absorption-related Processes (UNGAP) was established through COST, a funding organisation of the European Union supporting translational research across Europe. In this review of the UNGAP Working group "Food-Drug Interface", the different mechanisms that can lead to pharmacokinetic food-drug interactions are discussed and summarised from different expert perspectives. ispartof: EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES vol:134 pages:31-59 ispartof: location:Netherlands status: published

Opioids have been used for centuries, mostly as a sedative and to treat pain. Currently, they are used on a global scale for the treatment of acute and chronic pain in diseases as osteoarthritis, fibromyalgia, and low back pain. Binding of opioids on opioid receptors can cause a range of different effects such as changes in stress response, analgesia, motor activity and autonomic functions. This review provide a synthetic summary of the most recent literature on the use of drugs acting on mu-receptors to treat two prevalent functional bowel disorders, presenting with opposite bowel habit. Eluxadoline and naloxegol, methylnaltrexone and naldemedine are recently FDA and/or EMA approved drugs demonstrated to be effective and safe for treatment respectively of irritable bowel syndrome subtype diarrhea and opioid induced constipation.

Irritable bowel syndrome (IBS) remains one of the most common gastrointestinal disorders seen by clinicians in both primary and secondary care. Since publication of the last British Society of Gastroenterology (BSG) guideline in 2007, substantial advances have been made in understanding its complex pathophysiology, resulting in its re-classification as a disorder of gut-brain interaction, rather than a functional gastrointestinal disorder. Moreover, there has been a considerable amount of new evidence published concerning the diagnosis, investigation and management of IBS. The primary aim of this guideline, commissioned by the BSG, is to review and summarise the current evidence to inform and guide clinical practice, by providing a practical framework for evidence-based management of patients. One of the strengths of this guideline is that the recommendations for treatment are based on evidence derived from a comprehensive search of the medical literature, which was used to inform an update of a series of trial-based and network meta-analyses assessing the efficacy of dietary, pharmacological and psychological therapies in treating IBS. Specific recommendations have been made according to the Grading of Recommendations Assessment, Development and Evaluation system, summarising both the strength of the recommendations and the overall quality of evidence. Finally, this guideline identifies novel treatments that are in development, as well as highlighting areas of unmet need for future research.

Background Bisacodyl is a member of the diphenylmethane family and is considered to be a stimulant laxative. It has a dual prokinetic and secretory action and needs to be converted into the active metabolite bis‐(p‐hydroxyphenyl)‐pyridyl‐2‐methane (BHPM) in the gut to achieve the desired laxative effect. Bisacodyl acts locally in the large bowel by directly enhancing the motility, reducing transit time, and increasing the water content of the stool. A recent network meta‐analysis concluded that bisacodyl showed similar efficacy to prucalopride, lubiprostone, linaclotide, tegaserod, velusetrag, elobixibat, and sodium picosulfate for the primary endpoint of ≥3 complete spontaneous bowel movements (CSBM)/week and an increase of ≥1 CSBM/week over baseline. The meta‐analysis also found that bisacodyl may be superior to the other laxatives for the secondary endpoint of change from baseline in the number of spontaneous bowel movements per week in patients with chronic constipation. This observation stimulated the authors to review the available literature on bisacodyl, which has been available on the market since the 1950 s. Purpose The aim of the current review was to provide an overview of the historic background, structure, function, and mechanism of action of bisacodyl. Additionally, we discuss the important features and studies for bisacodyl to understand its peculiar characteristics and guide its use in clinical practice, but also stimulate research on open questions.

BACKGROUND Polyethylene glycol (PEG), bisacodyl, and prucalopride have been reported to be more effective than placebo in treating patients with constipation but about 50% of the patients still do not respond to these medications. Only bisacodyl and prucalopride are expected to directly stimulate the colonic motility in humans in vivo. As no previous study has done this, the aim of the study was to investigate the effect of PEG, bisacodyl, and prucalopride as compared to placebo on colonic motility assessed by means of the high-resolution manometry (HRM) in healthy subjects. METHODS Ten healthy subjects have been enrolled in an acute, open label, randomized, reader-blinded, crossover study and requested to undergo a colonoscopy-assisted HRM measuring their colonic motility before and after oral administration of 13.8 g (two doses) PEG, 10 mg bisacodyl, 2 mg prucalopride, and placebo. KEY RESULTS In the human prepared colon, oral administration of PEG significantly increases the number of low-amplitude long distance propagating contractions (p = 0.007 vs placebo) while bisacodyl significantly increases the number of high-amplitude propagating contractions (HAPCs) (all p

BACKGROUND Magnetic resonance imaging (MRI) of the colonic response to a macrogol challenge drink can be used to assess the mechanisms underlying severe constipation. We measured the intrasubject reproducibility of MRI measures of colonic function to aid their implementation as a possible clinical test. METHODS Healthy participants attended for MRI on two occasions (identical protocols, minimum 1 week apart). They underwent a fasted scan and then consumed the macrogol drink. Subjects were scanned at 60 and 120 minutes, with maximum value reached used for comparison. The colonic volume, water content, mixing of colonic content and the movement of the colon walls were measured. Coefficients of variation and intraclass correlation coefficients (ICC) were calculated. RESULTS Twelve participants completed the study: nine female, mean age 26 years (SD 5) and body mass index 24.8 kg/m2 (SD 3.2). All measures consistently increased above baseline following provocation with macrogol. The volume, water content and content mixing had good intrasubject reproducibility (ICC volume = 0.84, water content = 0.93, mixing = 0.79, P

INTRODUCTION: Gastrointestinal symptoms in irritable bowel syndrome (IBS) have been correlated with psychological factors using retrospective symptom assessment. However, real-time symptom assessment might reveal the interplay between abdominal and affective symptoms more reliably in a longitudinal perspective. The aim was to evaluate the association between stress and abdominal pain, using the Experience Sampling Method (ESM) as a real-time, repeated measurement method. METHODS: Thirty-seven patients with IBS (26 women; mean age 36.7 years) and 36 healthy controls (HC; 24 women; mean age 31.1 years) completed an electronic ESM during 7 consecutive days. Abdominal pain and stress were scored on an 11-point Numeric Rating Scale at a maximum of 10 random moments each day. RESULTS: Abdominal pain scores were 2.21 points higher in patients with IBS compared with those in HC (P < 0.001), whereas stress levels did not differ significantly (B: 0.250, P = 0.406). In IBS, a 1-point increase in stress was associated with, on average, 0.10 points increase in abdominal pain (P = 0.017). In HC, this was only 0.02 (P = 0.002). Stress levels at t = -1 were not a significant predictor for abdominal pain at t = 0 in both groups, and vice versa. DISCUSSION: Our results demonstrate a positive association between real-time stress and abdominal pain scores and indicate a difference in response to stress and not a difference in experienced stress per se. Furthermore, an in-the-moment rather than a longitudinal association is suggested. This study underlines the importance of considering the individual flow of daily life and supports the use of real-time measurement when interpreting potential influencers of abdominal symptoms in IBS. ispartof: CLINICAL AND TRANSLATIONAL GASTROENTEROLOGY vol:11 issue:7 ispartof: location:United States status: published

Background High-resolution manometric studies below the stomach are rare due to technical limitations of traditional manometry catheters. Consequently, specific motor patterns and their impact on gastric and small bowel function are not well understood. High-resolution manometry was used to record fed-state motor patterns in the antro-jejunal segment and relate these to fasting motor function. Methods Antro-jejunal pressures were monitored in 15 healthy females using fiber-optic manometry (72 sensors at 1 cm intervals) before and after a high-nutrient drink. Key results Postprandial motility showed a previously unreported transition point 18.8 cm (range 13-28 cm) beyond the antro-pyloric junction. Distal to the transition, a zone of non-propagating, repetitive pressure events (11.5 ± 0.5 cpm) were dominant in the fed state. We have named this activity, the duodeno-jejunal complex (DJC). Continuous DJC activity predominated, but nine subjects also exhibited intermittent clusters of DJC activity, 7.4 ± 4.9/h, lasting 1.4 ± 0.55 minutes, and 3.8 ± 1.2 minutes apart. DJC activity was less prevalent during fasting (3.6 ± 3.3/h; P = .04). 78% of fed and fasting state propagating antro-duodenal pressure events terminated proximally or at the transition point and were closely associated with DJC clusters. Conclusions and inferences High-resolution duodeno-jejunal manometry revealed a previously unrecognized transition point and associated motor pattern extending into the jejunum, consistent with the duodenal brake previously identified fluoroscopically. Timing suggests DJC activity is driven by chyme stimulating duodenal mucosal chemosensors. These findings indicate that the duodenum and proximal jejunum consists of two major functional motor regions.

Irritable bowel syndrome is a functional gastrointestinal disorder with symptoms including abdominal pain associated with a change in stool form or frequency. The condition affects between 5% and 10% of otherwise healthy individuals at any one point in time and, in most people, runs a relapsing and remitting course. The best described risk factor is acute enteric infection, but irritable bowel syndrome is also more common in people with psychological comorbidity and in young adult women than in the rest of the general population. The pathophysiology of irritable bowel syndrome is incompletely understood, but it is well established that there is disordered communication between the gut and the brain, leading to motility disturbances, visceral hypersensitivity, and altered CNS processing. Other less reproducible mechanisms might include genetic associations, alterations in gastrointestinal microbiota, and disturbances in mucosal and immune function. In most people, diagnosis can be made on the basis of clinical history with limited and judicious use of investigations, unless alarm symptoms such as weight loss or rectal bleeding are present, or there is a family history of inflammatory bowel disease or coeliac disease. Once the diagnosis is made, an empathetic approach is key and can improve quality of life and symptoms, and reduce health-care expenditure. The mainstays of treatment include patient education about the condition, dietary changes, soluble fibre, and antispasmodic drugs. Other treatments tend to be reserved for people with severe symptoms and include central neuromodulators, intestinal secretagogues, drugs acting on opioid or 5-HT receptors, or minimally absorbed antibiotics (all of which are selected according to predominant bowel habit), as well as psychological therapies. Increased understanding of the pathophysiology of irritable bowel syndrome in the past 10 years has led to a healthy pipeline of novel drugs in development.

Disorders of defecation and the pelvic floor affect around 10–15% of the population and are a problem commonly encountered by both gastroenterologists and GI surgeons alike. They require a comprehensive approach both with initial clinical examination and subsequent investigation, utilizing a range of both functional tests and imaging modalities, both of which are constantly evolving. This chapter will cover both the practical approach to anorectal motility investigation as well as its interpretation. This will include functional tests such as manometry and barostat recording as well as traditional imaging techniques using X-ray and newer MRI techniques.

The healthy colon absorbs nutrients, facilitates fermentation, stores feces and evacuates them under conscious control. In humans, the investigation of colonic transit and motility has developed substantially over the last 2 decades to allow assessment of the differing motor patterns required to complete the multiple physiological tasks. Recent advances in technologies have revolutionized our understanding of colonic motility, providing new insights on what we knew. Here, we discuss various novel techniques for assessing colonic transit and motility, highlighting their strengths and weaknesses.

The absorption of oral drugs is frequently plagued by significant variability with potentially serious therapeutic consequences. The source of variability can be traced back to interindividual variability in physiology, differences in special populations (age- and disease-dependent), drug and formulation properties, or food-drug interactions. Clinical evidence for the impact of some of these factors on drug pharmacokinetic variability is mounting: e.g. gastric pH and emptying time, small intestinal fluid properties, differences in pediatrics and the elderly, and surgical changes in gastrointestinal anatomy. However, the link of colonic factors variability (transit time, fluid composition, microbiome), sex differences (male vs. female) and gut-related diseases (chronic constipation, anorexia and cachexia) to drug absorption variability has not been firmly established yet. At the same time, a way to decrease oral drug pharmacokinetic variability is provided by the pharmaceutical industry: clinical evidence suggests that formulation approaches employed during drug development can decrease the variability in oral exposure. This review outlines the main drivers of oral drug exposure variability and potential approaches to overcome them, while highlighting existing knowledge gaps and guiding future studies in this area. ispartof: EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES vol:162 ispartof: location:Netherlands status: published

Background: Effective management of irritable bowel syndrome (IBS), a common functional gastrointestinal disorder, can be challenging for physicians because of the lack of simple diagnostic tests and the wide variety of treatment approaches available. Objective: The objective of this article is to outline a simple algorithm for day-to-day clinical practice to help physicians navigate key stages to reaching a positive IBS diagnosis and guidance on how to prioritise the use of specific management strategies. Methods: This algorithm was based on the opinion of an expert panel evaluating current evidence. Results: The key principles forming the foundation of this evidence-supported algorithm are: confidently naming and explaining an IBS diagnosis for the patient, followed by assessment of key patient characteristics likely to influence the choice of therapy, such as predominant symptoms, and exploring the patient agenda and preferences. Consultation should always include education and reassurance with an explanatory model of IBS tailored to the patient. Individualised lifestyle changes, dietary modifications, pharmacological therapies, psychological strategies or a combination of interventions may be used to optimise treatment for each patient. Conclusion: The simple visual tools developed here navigate the key stages to reaching a positive diagnosis of IBS, and provide a stepwise approach to patient-centred management targeted towards the most bothersome symptoms. Establishing a strong patient-physician relationship is central to all stages of the patient journey from diagnosis to effective management.

Background: Denatonium benzoate (DB) has been shown to influence ongoing ingestive behavior and gut peptide secretion. Objective: We studied how the intragastric administration of DB affects interdigestive motility, motilin and ghrelin plasma concentrations, hunger and satiety ratings, and food intake in healthy volunteers. Design: Lingual bitter taste sensitivity was tested with the use of 6 concentrations of DB in 65 subjects. A placebo or 1 μmol DB/kg was given intragastrically to assess its effect on fasting gastrointestinal motility and hunger ratings, motilin and ghrelin plasma concentrations, satiety, and caloric intake. Results: Women (n = 39) were more sensitive toward a lingual bitter stimulus (P = 0.005) than men (n = 26). In women (n = 10), intragastric DB switched the origin of phase III contractions from the stomach to the duodenum (P = 0.001) and decreased hunger ratings (P = 0.04). These effects were not observed in men (n = 10). In women (n = 12), motilin (P = 0.04) plasma concentrations decreased after intragastric DB administration, whereas total and octanoylated ghrelin were not affected. The intragastric administration of DB decreased hunger (P = 0.008) and increased satiety ratings (P = 0.01) after a meal (500 kcal) in 13 women without affecting gastric emptying in 6 women. Caloric intake tended to decrease after DB administration compared with the placebo (mean ± SEM: 720 ± 58 compared with 796 ± 45 kcal; P = 0.08) in 20 women. Conclusions: Intragastric DB administration decreases both antral motility and hunger ratings during the fasting state, possibly because of a decrease in motilin release. Moreover, DB decreases hunger and increases satiety ratings after a meal and shows potential for decreasing caloric intake

Introduction: Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder which represents a major cost to healthcare services. IBS-D patients represent about one-third of the IBS population and are currently treated with antispasmodics, loperamide, bile acid sequestrants and antidepressants. Alosetron and rifaximin are also available in USA, ramosetron in Japan, Korea and Thailand and ondansetron as an off-label treatment.Areas covered: This article focuses on eluxadoline, a novel pharmacological agent that has recently been approved by both the FDA and EMA for treatment of patients with IBS-D.Expert commentary: The efficacy and safety of eluxadoline in treating bowel habit alterations and pain, both in the short and long-term, make the drug a welcome addition to our therapeutic alternatives in IBS-D. Its positioning in any IBS algorithm will depend on the ‘real world’ prevalence of the small risk of sphincter of Oddi spasm and mild pancreatitis.

Various gastrointestinal (GI) factors affect drug and formulation behavior after oral administration, including GI transfer, motility, pH and GI fluid volume and composition. An in-depth understanding of these physiological and anatomical variables is critical for a continued progress in oral drug development. In this review, different methodologies (invasive versus non-invasive) to explore the impact of physiological variables on formulation behavior in the human GI tract are presented, revealing their strengths and limitations. The techniques mentioned allow for an improved understanding of the role of following GI variables: gastric emptying (magnetic resonance imaging (MRI), scintigraphy, acetaminophen absorption technique, ultrasonography, breath test, intraluminal sampling and telemetry), motility (MRI, small intestinal/colonic manometry and telemetry), GI volume changes (MRI and ultrasonography), temperature (telemetry) and intraluminal pH (intraluminal sampling and telemetry). publisher: Elsevier articletitle: Exploring gastrointestinal variables affecting drug and formulation behavior: Methodologies, challenges and opportunities journaltitle: International Journal of Pharmaceutics articlelink: http://dx.doi.org/10.1016/j.ijpharm.2016.11.063 content_type: article copyright: © 2016 Elsevier B.V. All rights reserved. ispartof: International Journal of Pharmaceutics vol:59 issue:1-2 pages:79-97 ispartof: location:Netherlands status: published

Alterations in colonic motility are implicated in the pathophysiology of bowel disorders, but high-resolution manometry of human colonic motor function has revealed that our knowledge of normal motor patterns is limited. Furthermore, various terminologies and definitions have been used to describe colonic motor patterns in children, adults and animals. An example is the distinction between the high-amplitude propagating contractions in humans and giant contractions in animals. Harmonized terminology and definitions are required that are applicable to the study of colonic motility performed by basic scientists and clinicians, as well as adult and paediatric gastroenterologists. As clinical studies increasingly require adequate animal models to develop and test new therapies, there is a need for rational use of terminology to describe those motor patterns that are equivalent between animals and humans. This Consensus Statement provides the first harmonized interpretation of commonly used terminology to describe colonic motor function and delineates possible similarities between motor patterns observed in animal models and humans in vitro (ex vivo) and in vivo. The consolidated terminology can be an impetus for new research that will considerably improve our understanding of colonic motor function and will facilitate the development and testing of new therapies for colonic motility disorders., This Consensus Statement provides a conceptual and methodological framework to expand research on colonic motility in experimental animals and humans. The work is intended to facilitate the development of new drugs for common colonic motility disorders and of appropriate diagnostic and therapeutic algorithms for the management of paediatric and adult patients.

Background Irritable bowel syndrome with diarrhoea (IBS-D) affects up to 4% of the general population. Symptoms include frequent, loose, or watery stools with associated urgency, resulting in marked reduction of quality of life and loss of work productivity. Ondansetron, a 5HT3 receptor antagonist, has had an excellent safety record for over 20 years as an antiemetic, yet is not widely used in the treatment of IBS-D. It has, however, been shown to slow colonic transit and in a small randomised, placebo-controlled, cross-over pilot study, benefited patients with IBS-D. Methods This trial is a phase III, parallel group, randomised, double-blind, multi-centre, placebo-controlled trial, with embedded mechanistic studies. Participants (n = 400) meeting Rome IV criteria for IBS-D will be recruited from outpatient and primary care clinics and by social media to receive either ondansetron (dose titrated up to 24 mg daily) or placebo for 12 weeks. Throughout the trial, participants will record their worst abdominal pain, worst urgency, stool frequency, and stool consistency on a daily basis. The primary endpoint is the proportion of “responders” in each group, using Food and Drug Administration (FDA) recommendations. Secondary endpoints include pain intensity, stool consistency, frequency, and urgency. Mood and quality of life will also be assessed. Mechanistic assessments will include whole gut transit, faecal tryptase and faecal bile acid concentrations at baseline and between weeks 8 and 11. A subgroup of participants will also undergo assessment of sensitivity (n = 80) using the barostat, and/or high-resolution colonic manometry (n = 40) to assess motor patterns in the left colon and the impact of ondansetron. Discussion The TRITON trial aims to assess the effect of ondansetron across multiple centres. By defining ondansetron’s mechanisms of action we hope to better identify patients with IBS-D who are likely to respond. Trial registration ISRCTN, ISRCTN17508514, Registered on 2 October 2017. Electronic supplementary material The online version of this article (10.1186/s13063-019-3562-6) contains supplementary material, which is available to authorized users.

BACKGROUND. During proctography, rectal emptying is visually estimated by the reduction in rectal area. The correlation between changes in rectal area, which is a surrogate measure of volume, are unclear. Our aims were to compare the change in rectal area and volume during magnetic resonance (MR) proctography and to compare these parameters with rectal balloon expulsion time (BET). METHODS. In 49 healthy and 46 constipated participants, we measured BET and rectal area and volume with a software program before and after participants expelled rectal gel during proctography. KEY RESULTS. All participants completed both tests; 6 healthy and 17 constipated patients had a prolonged (>60 s) BET. During evacuation, the reduction in rectal area and volume was lower in participants with an abnormal than a normal BET (P

The gastrointestinal (GI) tract is one of the most popular and used routes of drug product administration due to the convenience for better patient compliance and reduced costs to the patient compared to other routes. However, its complex nature poses a great challenge for formulation scientists when developing more complex dosage forms such as those combining two or more drugs. Fixed dose combination (FDC) products are two or more single active ingredients combined in a single dosage form. This formulation strategy represents a novel formulation which is as safe and effective compared to every mono-product separately. A complex drug product, to be dosed through a complex route, requires judicious considerations for formulation development. Additionally, it represents a challenge from a regulatory perspective at the time of demonstrating bioequivalence (BE) for generic versions of such drug products. This report gives the reader a summary of a 2-day short course that took place on the third and fourth of November at the Annual Association of Pharmaceutical Scientists (AAPS) meeting in 2018 at Washington, D.C. This manuscript will offer a comprehensive view of the most influential aspects of the GI physiology on the absorption of drugs and current techniques to help understand the fate of orally ingested drug products in the complex environment represented by the GI tract. Through case studies on FDC product development and regulatory issues, this manuscript will provide a great opportunity for readers to explore avenues for successfully developing FDC products and their generic versions. ispartof: AAPS JOURNAL vol:21 issue:4 ispartof: location:United States status: published

Opioids have recently received much attention because of the epidemic in their use in some countries such as the USA and the UK. Concerns have been raised about the possibility that they can increase mortality in patients when used on a long-term basis. Moreover, they are known to induce paradoxical hyperalgesia as well as alterations of gut function. The analgesic properties of opioids are mediated by receptors located in the brain, but as opioid receptors are also expressed in the gastrointestinal tract, new drugs acting on these receptors have recently been developed to treat two functional disorders, namely irritable bowel syndrome with diarrhoea and opioid-induced constipation. The aim of this article is to highlight some interesting observations resulting from the development of these drugs in the field of functional gastrointestinal disorders.

Fluid sampling from the gastrointestinal (GI) tract has been applied as a valuable tool to gain more insight into the fluids present in the human GI tract and to explore the dynamic interplay of drug release, dissolution, precipitation and absorption after drug product administration to healthy subjects. In the last twenty years, collaborative initiatives have led to a plethora of clinical aspiration studies that aimed to unravel the luminal drug behavior of an orally administered drug product. The obtained drug concentration-time profiles from different segments in the GI tract were a valuable source of information to optimize and/or validate predictive in vitro and in silico tools, frequently applied in the non-clinical stage of drug product development. Sampling techniques are presently not only being considered as a stand-alone technique but are also used in combination with other in vivo techniques (e.g., gastric motility recording, magnetic resonance imaging (MRI)). By doing so, various physiological variables can be mapped simultaneously and evaluated for their impact on luminal drug and formulation behavior. This comprehensive review aims to describe the history, challenges and opportunities of the aspiration technique with a specific focus on how this technique can unravel the luminal behavior of drug products inside the human GI tract by providing a summary of studies performed over the last 20 years. A section 'Best practices' on how to perform the studies and how to treat the aspirated samples is described. In the conclusion, we focus on future perspectives concerning this technique. ispartof: EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES vol:155 ispartof: location:Netherlands status: published

The purpose of this study was to explore gastrointestinal dissolution, supersaturation and precipitation of the weakly basic drug posaconazole in humans, and to assess the impact of formulation pH and type on these processes. In a cross-over study, two posaconazole suspensions (40 mg dispersed in 240 mL water at pH 1.6 and pH 7.1, respectively) were intragastrically administered; subsequently, gastric and duodenal fluids were aspirated. In parallel, blood samples were collected. Additionally, posaconazole was intragastrically administered as a solution (20 mg in 240 mL water, pH 1.6). When posaconazole was administered as an acidified suspension, supersaturated duodenal concentrations of posaconazole were observed for approximately 45 min. However, extensive intestinal precipitation was observed. Administration of the neutral suspension resulted in subsaturated concentrations with a mean duodenal AUC0-120 min and Cmax being approximately twofold lower than for the acidified suspension. The mean plasma AUC0-8 h of posaconazole was also twofold higher following administration of the acidified suspension. Similar to the acidified suspension, significant intestinal precipitation (up to 92%) was observed following intragastric administration of the posaconazole solution. This study demonstrated for the first time the gastrointestinal behavior of a weakly basic drug administered in different conditions, and its impact on systemic exposure. publisher: Elsevier articletitle: Supersaturation and Precipitation of Posaconazole Upon Entry in the Upper Small Intestine in Humans journaltitle: Journal of Pharmaceutical Sciences articlelink: http://dx.doi.org/10.1002/jps.24690 content_type: article copyright: © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved. ispartof: Journal Of Pharmaceutical Sciences vol:105 issue:9 pages:2677-2684 ispartof: location:Paris status: published

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder, which represents a major cost to healthcare services. Current pharmacological treatment includes fibre supplements, antispasmodics, laxatives, loperamide and antidepressants. This article reviews the novel pharmacological treatments already or recently approved for patients with IBS-C (lubiprostone, linaclotide) and IBS-D (alosetron, ramosetron, rifaximin, eluxadoline). Furthermore, results for drugs in development (plecanatide, ibudutant and ebastine) or used in chronic constipation or for other indications, with potential application in IBS (prucalopride, elobixibat, mesalazine, ondansetron and colesevelam) are also reviewed.

In the treatment of irritable bowel syndrome (IBS), loperamide seems efficacious for diarrhea and ispaghula for constipation, while musculotropic spasmolytics may relieve abdominal pain. Antidepressants were found to be efficacious for abdominal pain, but their tolerance may be problematic and the therapeutic effect varied largely between trials. While meta-analyses suggest efficacy of probiotics as a group, the quality of the trials is often suboptimal and there is large variability. Lubiprostone, a chloride channel activator, and linaclotide, a guanylyl cyclase-C agonist, showed favorable effects on multiple symptoms in IBS with constipation. For IBS with diarrhea (IBS-D), the 5-HT3 receptor antagonist ramosetron showed efficacy in men and women, but is currently only approved in Japan. A multicenter study with the anti-emetic 5-HT3 receptor antagonist ondansetron showed efficacy on stool pattern in IBS-D. The poorly absorbable antibiotic rifaximin and eluxadoline, a mu opioid receptor agonist and delta antagonist, both showed efficacy in phase III trials in IBS-D and were approved by the FDA. Eluxadoline was associated with increased occurrence of sphincter of Oddi spasm and biliary pancreatitis. The non-pharmacological treatment of IBS, with dietary interventions (mainly gluten elimination and low FODMAP (fructose, oligo-, di-, monosaccharides and polyols)) has received a lot of attention lately. While responder rates vary across studies, perhaps based on regional variations in dietary intake of FODMAPs, the dietary approach seems to have acquired recognition as a valid therapeutic alternative. Long-term studies and comparative studies with pharmacotherapy, as well as elucidation of the underlying mechanisms of action, are needed.

Objective The gastrointestinal environment in which drug products need to disintegrate before the drug can dissolve and be absorbed has not been studied in detail due to limitations, especially invasiveness of existing techniques. Minimal in vivo data is available on undisturbed gastrointestinal motility to improve relevance of predictive dissolution models and in silico tools such as physiologically-based pharmacokinetic models. Recent advances in magnetic resonance imaging methods could provide novel data and insights that can be used as a reference to validate and, if necessary, optimize these models. The conventional method for measuring gastrointestinal motility is via a manometric technique involving intubation. Nevertheless, it is feasible to measure gastrointestinal motility with magnetic resonance imaging. The aim of this study was is to develop and validate a magnetic resonance imaging method using the most recent semi-automated analysis method against concomitant perfused manometry method. Material and methods Eighteen healthy fasted participants were recruited for this study. The participants were intubated with a water-perfused manometry catheter. Subsequently, stomach motility was assessed by cine-MRI acquired at intervals, of 3.5min sets, at coronal oblique planes through the abdomen and by simultaneous water perfused manometry, before and after administration of a standard bioavailability / bioequivalence 8 ounces (~240mL) drink of water. The magnetic resonance imaging motility images were analysed using Spatio-Temporal Motility analysis STMM techniques. The area under the curve of the gastric motility contractions was calculated for each set and compared between techniques. The study visit was then repeated one week later. Results Data from 15 participants was analysed. There was a good correlation between the MRI antral motility plots area under the curve and corresponding perfused manometry motility area under the curve (r = 0.860) during both antral contractions and quiescence. Conclusion Non-invasive dynamic magnetic resonance imaging of gastric antral motility coupled with recently developed, semi-automated magnetic resonance imaging data processing techniques correlated well with simultaneous, ‘gold standard’ water perfused manometry. This will be particularly helpful for research purposes related to oral absorption where the absorption of a drug is highly depending on the underlying gastrointestinal processes such as gastric emptying, gastrointestinal motility and availability of residual fluid volumes. Clinical trial This trial was registered at ClinicalTrials.gov as NCT03191045.

Background Food hypersensitivity is characterized by a wide range of symptoms. The relationship between symptoms and food is more frequently suspected than objectively proven. Basophil activation test (BAT) is based on the evaluation of activation markers on blood basophils in vitro stimulated with drugs or allergens. The aim of the study was to evaluate the usefulness of BAT when introduced in the routine work-up of suspected food hypersensitivity. Methods BAT was requested in subjects with food adverse reactions when a discrepancy existed among history and skin prick test (SPT) and/or specific IgE. Data from 150 subjects were analysed using CD63 as basophil activation marker. Thirty controls were evaluated for cut-offs. Immunoblots was performed with the sera of representative subjects positive for BAT and negative for SPT and sIgE. Results 1,024 BAT were carried out, the agreement (positive/positive and negative/negative) was 78.5% for BAT vs. SPT and 78.3% for BAT vs. IgE. Atopic patients, but not atopic controls, more frequently had a positive BAT than non-atopic patients (P

Functional dyspepsia is a prevalent functional gastrointestinal disorder that can significantly erode the quality of life of sufferers and places a major cost burden on healthcare services. In this article, we review the recent literature, selecting the information we consider relevant since it has changed our clinical management of patients with functional dyspepsia.

Intragastric administration of the bitter tastant denatonium benzoate inhibits the increase of motilin plasma levels and antral contractility. While these findings suggest that gastrointestinal bitter taste receptors could be new targets to modulate gastrointestinal motility and hormone release, they need confirmation with other bitter receptor agonists. The primary aim was to evaluate the effect of intragastric administration of the bitter tastant quinine-hydrochloride (QHCl) on motilin and ghrelin plasma levels. Secondly, we studied the effect on interdigestive motility. Methods: Ten healthy female volunteers were recruited (33±4 years; 22±0.5 kg/m²). Placebo or QHCl (10 µmol/kg) was administered intragastrically through a nasogastric feeding tube after an overnight fast in a single-blind randomized fashion. Administration started 20 min after the first phase III of the migrating motor complex. The measurement continued for another 2 hours after the administration. Blood samples were collected every 10 min with the baseline sample taken 10 min prior to administration. Key results: The increase in plasma levels of motilin (administration; p=0.04) and total ghrelin (administration; p=0.02) was significantly lower after QHCl. The fluctuation of octanoylated ghrelin was reduced after QHCl (time by administration; p=0.03). Duodenal motility did not differ. The fluctuation of antral activity differed over time between placebo and QHCl (time by administration; p=0.03). Conclusions: QHCl suppresses the increase of both motilin and ghrelin plasma levels. Moreover, QHCl reduced the fluctuation of antral motility. These findings confirm the potential of bitter taste receptors as targets for modifying interdigestive motility in man.

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal (GI) disorder that can significantly erode the quality of life (QoL) of sufferers and places a major cost burden on healthcare services. This paper reviews the literature on the impact of IBS on healthcare services and society, including a recent report on the subject, in order to formulate a plan for the future. A completely different model of care for these patients is recommended based on this review and the experience of the two authors who have been treating patients with functional GI disorders for 20 and 35 years, respectively.

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder which represents a major cost to health-care services. The diagnosis of IBS is currently performed by means of symptom-based diagnostic criteria, but there has been an ongoing interest in developing biomarkers which could simplify the diagnosis and/or evaluating the effect of treatments. This article reviews the current literature concerning the proposed biomarkers including those of altered gut motility, of visceral hypersensitivity, of abnormal brain mechanisms, of serum, fecal and mucosal inflammation and of increased intestinal permeability.

Introduction: A number of new medications were recently demonstrated to be more effective than placebo in treating chronic constipation, including the intestinal chloride channel activator lubiprostone, the prokinetic selective 5-HT4 receptor agonist prucalopride and the guanylate cyclase-C agonist linaclotide. Recent publications have also revisited traditional laxatives like PEG. Moreover, a number of pharmacological treatments are in development and these include another guanylate cyclase-C agonist, plecanatide and an ileal bile acid transporter inhibitor, elobixibat. Areas covered: This review focuses on the pharmacology, efficacy and safety profile of prucalopride, linaclotide, plecanatide and elobixibat. Expert opinion: The possible present or future clinical application of prucalopride, linaclotide, plecanatide and elobixibat in both chronic constipation and irritable bowel syndrome with constipation is reported, and some considerations on the possible role of PEG taking into account recent literat...

Background An altered anorectal function is reported after chemoradiotherapy (CRT) and surgery for rectal cancer. Aim The aim of this study was to clarify the relative contribution of neoadjuvant chemoradiation and surgical resection on the impairment of anorectal function as evaluated by anorectal manometry. Methods Thirty-nine patients with rectal cancer, who underwent neoadjuvant CRT and laparoscopic rectal resection, were evaluated with the Pescatori Faecal Incontinence score, and with anorectal manometry: before neoadjuvant therapy (T0), after neoadjuvant therapy and before surgery (T1), 12 months after stoma closure (T2). Results Resting and/or maximum squeeze pressure and/or volume thresholds for urgency were below the normal values in 12 (30%) patients at baseline. After CRT the mean resting pressure significantly decreased (p = 0.007). Surgery determined a significantly decrease of the resting pressure (p = 0.001), of the maximum squeeze pressure (p = 0.001) and of the volume threshold for urgency (p = 0.001). Impairment of continence was reported by 5, 11 and 18 patients at T0, T1 and T2, with a mean incontinence score of 3, 3.8 and 3.9 respectively. Conclusions CRT is detrimental to the function of the internal anal sphincter. Rectal resection significantly affects both internal and external anal sphincter function and the maximum tolerated volume of the neo-rectum, particularly in patients with low rectal cancer, significantly impairing anal continence.

Background: Only few studies have applied high-resolution manometry (HRM) to the study of colonic motility in adults and none of them have concurrently evaluated colonic and anal motor activity. Aims: To evaluate colonic and anal motor activity by means of HRM in healthy subjects. As the present study revealed the presence of a new colonic motor pattern (pan-colonic pressurizations) in healthy subjects, three additional studies were conducted: the first and the second to exclude that this motor event results from an artefact due to abdominal wall contraction and to confirm its modulation by cholinergic stimulation and the third, as pilot study, to test the hypothesis that this colonic pattern is defective in patients with chronic constipation refractory to current pharmacological treatments. Methods: In both volunteers and patients the HRM catheter was advanced proximally during colonoscopy. Results: In all subjects, pressure increases of 15±3 mmHg and 24±4s simultaneously occurring in all colonic sensors (pan-colonic pressurizations), associated with anal sphincter relaxation were identified. Subjects had 85±38 pan-colonic pressurizations which increased significantly during meal (p=0.007) and decreased afterward (p=0.01), and were correlated with feelings of and desire to evacuate gas. The mean number of propagating sequences was 47±39, and only retrograde increased significantly postprandially (p=0.01). Pan-colonic pressurizations differed from strain artifacts and significantly increased after prostigmine. In patients pan-colonic pressurizations were significantly reduced as compared to volunteers. Conclusions: Pan-colonic pressurizations associated with relaxations of the anal sphincter represent a new colonic motor pattern which seems to be defective in patients with treatment-refractory chronic constipation and may play a role in the transport of colonic gas and in the facilitation of the propagating sequences-induced colonic transport.

Cine cardiac MRI is generally accepted as the "gold-standard" for functional myocardial assessment. It only took a few years after the development of commercial MRI systems for functional cardiac imaging to be developed, with electrocardiogram (ECG)-gated cine imaging first reported in 1988. The function of the gastrointestinal (GI) tract is more complex to study compared to the heart. However, the idea of having a non-invasive tool to study the GI function that also allows the concurrent assessment of different aspects of this function has become more and more attractive in the gastroenterological field. This review summarises key literature of the last 5 years to describe the current status of MRI in respect to the evaluation of GI function, highlighting the gaps and challenges and the future prospects. As the clinical application of a new technique requires that its clinical utility is confirmed by demonstration of its ability to enable clinicians to make a diagnosis and/or predict the treatment response, this review also considers whether or not this has been achieved, and how MRI has been validated against techniques currently recognised as the gold standard in clinical practice.

While the pharmacological armamentarium for chronic constipation has expanded over the past few years, a substantial proportion of constipated patients do not respond to these medications. This review summarizes the pharmacological and behavioral options for managing constipation and details the management of refractory constipation. Refractory constipation is defined as an inadequate improvement in constipation symptoms evaluated with an objective scale despite adequate therapy (ie, pharmacological and/or behavioral) that is based on the underlying pathophysiology of constipation. Minimally invasive (ie, rectal irrigation and percutaneous endoscopic colostomy) and surgical therapies are used to manage refractory constipation. This review appraises these options, and in particular, percutaneous endoscopic colostomy, which as detailed by an article in this issue, is a less invasive option for managing refractory constipation than surgery. While these options benefit some patients, the evidence of the risk: benefit profile for these therapies is limited.

BACKGROUND: Three previous studies from the same institution have reported that transoral incisionless fundoplication (TIF) with the EsophyX device is effective for creating a continent gastroesophageal valve and for good functional results as measured only by pH-metry in patients with gastroesophageal reflux disease (GERD). The objective of the present study was to evaluate the effect of TIF on symptoms, use of proton pump inhibitors (PPI), esophageal motility, and pH-impedance in patients with symptomatic GERD. METHODS: Twenty consecutive patients were enrolled to complete the GERD-HRQL and GERD-QUAL questionnaires while on and off PPI. They were also examined by upper gastrointestinal (GI) endoscopy to determine Hill grade and Jobe length of the gastroesophageal valve, and to check for hiatal hernia and esophagitis, esophageal manometry, and pH-impedance before and 6 months after TIF. RESULTS: Six months after TIF, the GERD-HRLQ and GERD-QUAL scores off-PPI therapy and the number of total and acid pH-impedance refluxes were significantly reduced (p < 0.05). The PPI had been completely stopped in 55% of the patient and was reduced in 22% of the patients. CONCLUSIONS: At 6-month follow-up, TIF performed using the EsophyX device reduces symptoms and pH-impedance refluxes, allowing interruption or reduction of PPI use in 78% of patients with GERD.

Background Tachykinins (TKs) are a family of endogenous peptides widely expressed in the central and in the peripheral nervous systems as well as in the gastrointestinal (GI) tract. They act as full agonists at three different membrane receptors neurokinin (NK) 1, NK2, and NK3, which are G protein-coupled receptors and in the GI tract are expressed both on neurons and effector cells. Purpose This article reviews the literature concerning the role of TKs in the GI tract function in physiological and pathological conditions and their potential relevance in the treatment of functional GI disorders with particular reference to irritable bowel syndrome (IBS). The efficacy of NK1 antagonists in chemotherapy-induced and postoperative nausea and vomiting is well established. While pharmacodynamic studies have reported conflicting and negative results concerning the effects of NK1 and of NK3 antagonists, respectively, on the GI tract function in humans, clinical studies applying the NK3 antagonist talnetant in IBS-D were negative. Pharmacodynamic studies applying NK2 antagonists have suggested a role for antagonism of NK2 receptors in modulation of GI chemical-induced altered motility and of stress-induced altered bowel habits. Clinical studies and in particular a recently completed Phase 2 study have reported that the NK2 antagonist ibodutant is effective and safe in treating symptoms of D-IBS, especially in females.

With increasing chronic opioid use, opioid-induced constipation (OIC) is becoming a relevant clinical challenge. Presently, only few treatments have been demonstrated to be more effective than placebo in treating OIC but most of them have a restricted clinical application because of side effects. Naloxegol , an orally administered, peripherally acting, μ-opioid receptor antagonist (PAMORA), was developed for the treatment of OIC.This review summarizes published information and presentations at meetings on the effects of naloxegol in OIC. Pharmacodynamic studies have demonstrated that naloxegol inhibits gastrointestinal opioid effects while preserving central analgesic actions. Phase II and Phase III studies in patients with non-cancer OIC have confirmed the efficacy of naloxegol to inhibit OIC, and the most consistent efficacy was seen with the 25 mg dose once daily. Adverse events were mainly gastrointestinal in origin and usually transient and mild. There were no signs of opioid withdrawal in the studies. Safety and tolerability were also shown in a long-term safety study. Regulatory authorities have recently approved the use of naloxegol in OIC.Naloxegol is the first approved, orally available PAMORA. The drug has the potential to substantially improve management of OIC patients.