A randomised trial of ondansetron for the treatment of irritable bowel syndrome with diarrhoea

Continuous administration of ramosetron with patient-controlled analgesia after laparoscopic distal gastrectomy does not delay postoperative bowel function recovery: A prospective, randomized, double-blinded study

BACKGROUND

Currently, 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists are indicated to slow gastrointestinal motility in the diarrhea-predominant subtype of irritable bowel syndrome. They are commonly used to prevent or treat postoperative nausea and vomiting (PONV) and opioid-induced nausea and vomiting (OINV). We conducted a prospective, randomized, double-blinded study to investigate whether the continuous administration of ramosetron, a selective 5-HT3 receptor antagonist, for preventing PONV and/or OINV after laparoscopic distal gastrectomy (LDG) might influence bowel function recovery.

METHODS

Patients scheduled to undergo LDG were randomly assigned to 1 of 3 treatment regimens: no prophylactic ramosetron (Group C); ramosetron 0.6 mg added to 2-day intravenous patient-controlled analgesia (IV-PCA) (Group R0.6); and ramosetron 1.2 mg added to 2-day IV-PCA (Group R1.2). Postoperative recovery profiles of bowel function, incidence of postoperative nausea/vomiting and pain, and perioperative data that affected bowel function recovery were evaluated.

RESULTS

Seventy-three patients completed the study protocol. Parameters associated with postoperative recovery of bowel function, such as time to first flatus, time to first bowel movement, time to first defecation, and time to commencement of soft diet, were not significantly different between the 3 groups. The incidence of nausea 2 to 24 hours after surgery was significantly lower in Group R0.6 (20.0%) and Group R1.2 (12.5%) than in Group C (45.8%) (P < .022). The ratio of complete response 2 to 24 hours after surgery was significantly higher in Group R0.6 (80.0%) and Group R1.2 (87.5%) than in Group C (54.2%) (P < .022). The incidence of retching 24 to 48 hours after surgery was significantly lower in Group R0.6 (0.0%) and Group R1.2 (4.2%) than in Group C (16.7%) (P < .043).

CONCLUSION

Continuous administration of ramosetron with patient-controlled analgesia to prevent PONV and OINV after LDG did not delay postoperative bowel function recovery.

Chronic abdominal pain in irritable bowel syndrome - current and future therapies

INTRODUCTION

Irritable bowel syndrome (IBS) is a functional gut disorder that typically manifests in early adult years. One of the two major symptoms of the disease is chronic, visceral pain. The patients report pain as the most distressing symptom with the greatest impact on quality of life, challenging both to patients and healthcare providers. Areas covered: This review focuses on the pathophysiology of abdominal pain in IBS and describes current treatment possibilities. It also covers latest findings that may lead to novel pharmacological options in IBS pain management. Expert commentary: Pain is the main contributor to severity in IBS. Seeking pain alleviation is the most common reason that IBS sufferers consult with their physicians. Not all patients report being satisfied with available treatments for pain in IBS and there is a pressing need to find new, more efficient therapies for this syndrome.

Review of synthetic human faeces and faecal sludge for sanitation and wastewater research

Investigations involving human faeces and faecal sludge are of great importance for urban sanitation, such as operation and maintenance of sewer systems, or implementation of faecal sludge management. However, working with real faecal matter is difficult as it not only involves working with a pathogenic, malodorous material but also individual faeces and faecal sludge samples are highly variable, making it difficult to execute repeatable experiments. Synthetic faeces and faecal sludge can provide consistently reproducible substrate and alleviate these challenges. A critical literature review of simulants developed for various wastewater and faecal sludge related research is provided. Most individual studies sought to develop a simulant representative of specific physical, chemical, or thermal properties depending on their research objectives. Based on the review, a suitable simulant can be chosen and used or further developed according to the research needs. As an example, the authors present such a modification for the development of a simulant that can be used for investigating the motion (movement, settling and sedimentation) of faeces and their physical and biological disintegration in sewers and in on-site sanitation systems.

Diagnosis and Management of Fecal Incontinence

PURPOSE OF REVIEW

The purpose of this review is to highlight current and newer therapeutic approaches to treat fecal incontinence in patients who do not respond to conservative measures.

RECENT FINDINGS

Neurostimulation techniques, injection of bulking agents, and radiofrequency energy delivery to the anal canal have been proposed and tested for fecal incontinence over the last decade. Sacral stimulation is both effective and durable and is now the most popular of the invasive techniques whereas percutaneous tibial stimulation, radiofrequency energy, and bulking agents are either less effective or their evaluation has been handicapped by suboptimal study designs. The precise indications for the new vaginal control device and anal plugs remain to be established. The magnetic anal sphincter is disappointing. Stem cell therapy is a potentially exciting approach, which is in its infancy. There continues to be an unmet need for innovative approaches to patients with fecal incontinence who do not respond to conservative measures. The efficacy of current and future therapies should be assessed using criteria more stringent than has been used in the past to provide a more realistic assessment of meaningful efficacy.

Advancements in drug development for diarrhea-predominant irritable bowel syndrome

INTRODUCTION

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common disorder characterized by a complex pathophysiology hampering optimal targeted drug development. Recent advances in our understanding of key underlying mechanisms prompted novel therapeutics including novel pharmacological approaches.

AREAS COVERED

This review summarizes the latest advancements in the pipeline of IBS-D drugs focusing on new pharmacological targets, efficacy and safety of medicinal products considering the recent harmonization of regulatory requirements by the FDA and the EMA.

EXPERT OPINION

The new 5-HT₃ receptor antagonist ramosetron appears a promising therapeutic approach devoid of significant adverse events, although it is presently unavailable in Western countries, most likely because of the precautionary approach taken by regulatory agencies with this drug class. New pharmacological concepts on full agonists/antagonists, mixed-receptor activity and novel drug targets may streamline the present drug pipeline along with the adherence on new regulatory guidelines on outcome measures. Eluxadoline can be taken as an example of this paradigm shift. It has now been granted marketing authorization for IBS-D on both sides of the Atlantic, but it is still considered as a second-line agent by the NICE. There is still much work to be done to fully cover clinical needs of patients with IBS-D.

New therapies in Irritable Bowel Syndrome: what works and when

PURPOSE OF REVIEW

The purpose of this review is to examine the evidence supporting the use of recently developed pharmacological treatments for IBS together with new evidence supporting more traditional therapies in order to understand where the new agents are best used in the treatment pathway.

RECENT FINDINGS

There is evidence to support the use of traditional treatments such as antispasmodics, antidepressants and dietary alteration in IBS. New therapeutic agents such as Linaclotide, Lubiprostone, Plecanatide, Rifaxamin and Eluxadoline are all more effective than placebo in treating symptoms of IBS with Tenapanor being a promising new agent. The majority of patients, however, treated with these medications remain symptomatic and they are not suitable for use in all patients.

SUMMARY

Traditional treatments such as antispasmodics, antidepressants, dietary and lifestyle modifications retain their importance in the treatment of IBS with the newer agents to be considered wherever these treatments are ineffective or poorly tolerated.

Diabetes Mellitus and the Colon

OPINION STATEMENT

Diabetes mellitus (DM) can affect the structure and function of the colon promoting commonly encountered lower gastrointestinal symptoms such as constipation, diarrhea, abdominal distention, bloating, and abdominal pain. Specific colonic disorders for which adults with DM are at greater risk include chronic constipation, enteropathic diarrhea, colorectal cancer (CRC), inflammatory bowel disease, microscopic colitis, and Clostridium difficile colitis. Smooth muscle structure and function, density of the interstitial cells of Cajal, and the health and function of the autonomic and enteric nerves of the colon are all potential affected by DM. These effects can in turn lead to alterations in colon motility, visceral sensation, immune function, endothelial function, and the colonic microbiome. The evaluation and treatment for slow transit constipation as well as pelvic floor dysfunction should be considered when constipation symptoms are refractory to initial treatment measures. DM-related medications and small bowel conditions such as celiac disease and small intestinal bowel overgrowth should be considered and excluded before a diagnosis of enteropathic diarrhea is made. Given the higher risk of CRC, adults with DM should be appropriately screened and may require a longer bowel preparation to ensure an adequate evaluation.

Eluxadoline in irritable bowel syndrome with diarrhea: rationale, evidence and place in therapy

Irritable bowel syndrome (IBS) is the most common gastrointestinal (GI) disorder worldwide, however treatment options for diarrhea-predominant IBS (IBS-D) remain limited. Eluxadoline, a µ- and κ-opioid receptor agonist and δ-opioid receptor antagonist, was recently approved for the treatment of IBS-D. A novel compound first described in 2008, eluxadoline was shown to normalize GI transit, with a subsequent phase I demonstrating its safety and tolerability in healthy adults. In 2016, two randomized, double-blind, placebo-controlled phase III trials studying eluxadoline use at 75 mg and 100 mg twice daily over 26 weeks demonstrated a significant improvement in stool consistency and many global symptoms of IBS. However, the data did not demonstrate a significant advantage over placebo using the United States Food and Drug Administration (US FDA) and European Medicines Agency (EMA) endpoints for abdominal pain. Safety and tolerability data, pooled from both phase II and III studies, suggest that eluxadoline is generally well tolerated with the most common adverse events (AEs) occurring in approximately 3-8% of patients and included nausea, constipation, and abdominal pain. The most common serious adverse event (SAE) is pancreatitis, which had a 0.4% incidence. Recent US FDA reports reporting severe pancreatitis and sphincter of Oddi dysfunction after short-term use of eluxadoline in patients without a gallbladder has added a history of cholecystectomy as an important contraindication. Eluxadoline is also contraindicated in patients with a history of biliary duct obstruction, sphincter of Oddi dysfunction, active alcohol abuse, history of pancreatitis or known pancreatic duct obstruction, severe hepatic impairment, severe or chronic constipation, or known mechanical gastrointestinal obstruction. As a new drug to enter the IBS-D market, the place of eluxadoline in the hierarchy of IBS treatments is still to be determined. In this article, we review the development and clinical trial data behind the approval of eluxadoline with a focus on safety data and its use in clinical practice.

Ondansetron treatment reduces rotavirus symptoms-A randomized double-blinded placebo-controlled trial

Background

Rotavirus and norovirus cause acute gastroenteritis with severe diarrhoea and vomiting, symptoms that may lead to severe dehydration and death. The objective of this randomized double-blinded placebo-controlled study was to investigate whether ondansetron, a serotonin receptor antagonist could attenuate rotavirus- and norovirus-induced vomiting and diarrhoea, which would facilitate oral rehydration and possibly accelerate recovery and reduce need for hospitalization.

Methods

Children with acute gastroenteritis, aged 6 months to 16 years where enrolled (n = 104) and randomized to one single oral dose (0.15mg/kg) of ondansetron (n = 52) or placebo (n = 52). The number of diarrhoea and vomiting episodes during the 24 hours following treatment was reported as well as the number of days with symptoms. Pathogens in faeces were diagnosed by real-time PCR. Outcome parameters were analyzed for rotavirus- and norovirus-positive children.

Results

One dose of oral ondansetron reduced duration of rotavirus clinical symptoms (p = 0.014), with a median of two days. Furthermore, ondansetron reduced diarrhea episodes, most pronounced in children that had been sick for more than 3 days before treatment (p = 0.028).

Conclusion

Ondansetron may be a beneficial treatment for children with rotavirus gastroenteritis.

Trial registration

European Clinical Trial Database EudraCT 2011-005700-15.

Pharmacotherapy for Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a disorder of the brain-gut axis; the pathophysiological mechanisms include altered colonic motility, bile acid metabolism, neurohormonal regulation, immune dysfunction, alterations in the epithelial barrier and secretory properties of the gut. This article reviews the mechanisms, efficacy, and safety of current pharmacotherapy, and medications that are in phase III trials for the treatment of IBS. There remains a significant unmet need for effective treatments-particularly for the pain component of IBS-although the introduction of drugs directed at secretion, motility and a non-absorbable antibiotic provide options for the bowel dysfunction in IBS.

Irritable Bowel Syndrome: Epidemiology, Pathophysiology, Diagnosis, and Treatment

Irritable bowel syndrome is a common medical condition that significantly alters patient quality of life and presents a series of diagnostic and treatment challenges to the treating provider. This article provides an updated and straightforward overview of the disease, its pathophysiology, diagnosis, and treatment options.

Irritable bowel syndrome diagnosis and management: A simplified algorithm for clinical practice

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.

Eluxadoline in the treatment of diarrhea-predominant irritable bowel syndrome

Eluxadoline is a novel drug approved for the management of diarrhea predominant irritable bowel syndrome (IBS-D). It has unique pharmacology and works on three different opioid receptors. Several Phase II and III clinical trials have demonstrated eluxadoline’s efficacy in reducing symptoms related to IBS-D. Clinical trial results and postmarketing reports show a risk of pancreatitis in patients without a gallbladder or those abusing alcohol. This review article will include information on clinical trial results related to IBS-D management as well as eluxadoline’s limitations.

Post-Infectious Irritable Bowel Syndrome

PURPOSE OF REVIEW

Post-infectious irritable bowel syndrome (PI-IBS) is characterized by persistent abdominal pain and diarrhea, typically following an episode of infectious gastroenteritis. The mechanisms that underlie IBS-D remain elusive, but PI-IBS provides a mechanistic model of this disorder. This review provides an up-to-date appraisal of the pathophysiology, clinical features, and management approaches for PI-IBS.

RECENT FINDINGS

Disordered immune reactions and release of cytokines with resultant gut inflammation and dysfunction appear to be key features of PI-IBS. Disordered brain-gut-microbiota interactions, type of infecting agent, and host-genetic susceptibility are risk factors but also are reasons for the varying spectrum of clinical severity. Although prognosis is generally good, symptoms and inflammation may persist for a long time. Symptomatic relief with antidiarrheals, antispasmodics, 5HT₃ antagonists, mesalamine, probiotics, and low-dose antidepressants remain the primary approaches, but in some difficult cases, a combination of drugs that target the pathophysiology may be helpful. PI-IBS has many overlapping features with IBS-D and shares similar pathophysiology and management approaches.

FFA2 activation combined with ulcerogenic COX inhibition induces duodenal mucosal injury via the 5-HT pathway in rats

Serotonin (5-HT), predominantly synthesized and released by enterochromaffin cells, is implicated in gastrointestinal symptoms such as emesis, abdominal pain, and diarrhea. Because luminal short-chain fatty acids (SCFAs) release 5-HT from enterochromaffin cells, which express the SCFA receptor free fatty acid receptor 2 (FFA2) in rat duodenum, we examined the effects of the selective FFA2 agonist phenylacetamide-1 (PA1) on duodenal 5-HT release with consequent bicarbonate secretion [duodenal bicarbonate secretion (DBS)] and on indomethacin (IND)-induced enteropathy. Intestinal injury was induced by IND (10 mg/kg sc) with or without PA1. We measured DBS in vivo in a duodenal loop perfused with PA1 while measuring 5-HT released in the portal vein. Duodenal blood flow was measured by laser-Doppler flowmetry. IND induced small intestinal ulcers with duodenal sparing. PA1 given with IND (IND + PA1) dose dependently induced duodenal erosions. IND + PA1-induced duodenal lesions were inhibited by the FFA2 antagonist GLPG-0974, ondansetron, or omeprazole but not by RS-23597 or atropine. Luminal perfusion of PA1 augmented DBS accompanied by increased portal blood 5-HT concentrations with approximately eight times more release at 0.1 mM than at 1 µM, with the effects inhibited by coperfusion of GLPG-0974. Luminal PA1 at 1 µM increased, but at 0.1 mM diminished, duodenal blood flow. Cosuperfusion of PA1 (0.1 mM) decreased acid-induced hyperemia, further reduced by IND pretreatment but restored by ondansetron. These results suggest that, although FFA2 activation enhances duodenal mucosal defenses, FFA2 overactivation during ulcerogenic cyclooxygenase inhibition may increase the vulnerability of the duodenal mucosa to gastric acid via excessive 5-HT release and 5-HT₃ receptor activation, implicated in foregut-related symptoms such as emesis and epigastralgia.NEW & NOTEWORTHY Luminal free fatty acid receptor 2 agonists stimulate enterochromaffin cells and release serotonin, which enhances mucosal defenses in rat duodenum. However, overdriving serotonin release with high luminal concentrations of free fatty acid 2 ligands such as short-chain fatty acids injures the mucosa by decreasing mucosal blood flow. These results are likely implicated in serotonin-related dyspeptic symptom generation because of small intestinal bacterial overgrowth, which is hypothesized to generate excess SCFAs in the foregut, overdriving serotonin release from enterochromaffin cells.

五羟色胺信号系统与胃肠道疾病的研究进展

五羟色胺(5-hydroxytryptamine, 5-HT)是脑肠轴调控路径中的一个重要组成部分. 5-HT信号系统在多种胃肠道疾病的发病机制中扮演重要的角色, 参与调节胃肠运动、感觉及分泌等功能. 5-HT的合成、释放、与特异性受体结合及再摄取过程中任意一个环节发生异常, 均与胃肠道功能紊乱的发生密切相关, 其不仅在功能性疾病中存在作用, 与器质性疾病也有很大的关系. 临床上5-HT受体激动剂、拮抗剂及选择性再摄取抑制剂已被广泛运用到多种胃肠道疾病的治疗中. 本文阐述了5-HT信号系统与胃肠道疾病病理生理的关系, 从而研究5-HT受体在胃肠道中的作用及其相关药物的临床效用, 为胃肠道疾病的防治提供理论依据.

Optimal dose of ramosetron in female patients with irritable bowel syndrome with diarrhea: A randomized, placebo-controlled phase II study

BACKGROUND

Previous studies showed that 5 μg of ramosetron, a serotonin (5-hydroxytryptamine: 5-HT)-3 receptor antagonist, is only effective in male patients with irritable bowel syndrome (IBS) with diarrhea (IBS-D). We hypothesized that either dose 1.25, 2.5, or 5 μg of ramosetron would be effective in female patients with IBS-D.

METHODS

This randomized, double-blind, placebo-controlled, phase II dose-finding exploratory trial included 409 female outpatients with IBS-D treated in Japan. They were administered oral placebo (n=102), or 1.25 μg (n=104), 2.5 μg (n=104), or 5 μg (n=99) of ramosetron once daily for 12 weeks after a 1-week baseline period. The primary endpoint was monthly responder rates of global improvement of IBS symptoms in the first month. Secondary endpoints included global improvement in the other months, abdominal pain/discomfort, weekly mean changes in the Bristol Stool Form Scale (BSFS), and IBS-QOL.

KEY RESULTS

Middle dose (2.5 μg) of ramosetron significantly improved abdominal pain/discomfort at second month (62.5%, P=.002), third month (60.6%, P=.005), and the last evaluation point (63.5%, P=.002) and weekly BSFS (P<.05) except at Week 8, 11, and 12 than placebo. IBS-QOL did not change. Ramosetron induced more constipation than placebo.

CONCLUSIONS & INFERENCES

The trial suggested that 2.5 μg of ramosetron is the most effective and least harmful option for treating female patients with IBS-D (Clinicaltrials.gov ID: NCT01274000).

New therapeutic options for IBS: the role of the first in class mixed µ- opioid receptor agonist and δ-opioid receptor antagonist (mudelta) eluxadoline

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.

Investigation of 5-HT3 receptor-triggered serotonin release from guinea-pig isolated colonic mucosa: a role of PYY-containing endocrine cell

The effect of a 5-HT₃ receptor-selective agonist SR57227A was investigated on the outflow of 5-hydroxytryptamine (5-HT) from isolated muscle layer-free mucosal preparations of guinea-pig colon. The mucosal preparations were incubated in vitro and the outflow of 5-HT from these preparations was determined by high-performance liquid chromatography with electrochemical detection. SR57227A (100μM) produced a tetrodotoxin-resistant and sustained increase in the outflow of 5-HT from the mucosal preparations. The SR57227A-evoked sustained 5-HT outflow was completely inhibited by the 5-HT₃ receptor antagonist ramosetron (1μM). The neuropeptide Y₁ receptor antagonist BIBO3304 (100nM) partially inhibited the SR57227A-evoked sustained 5-HT outflow, but the Y₂ receptor antagonist BIIE0246 (1μM) or the glucagon-like peptide-1 (GLP-1) receptor antagonist exendin-(9-39) (1μM), showed a minimal effect on the SR57227A-evoked sustained 5-HT outflow. In the presence of BIBO3304 (100nM) and exendin-(9-39) (1μM), SR57227A (100μM) failed to produce a sustained increase in the outflow of 5-HT. The Y₁ receptor agonist [Leu³¹, Pro³⁴]-neuropeptide Y (10nM), but not GLP-1-(7-36) amide (100nM), produced a sustained increase in the outflow of 5-HT. We found that 5-HT₃ receptor-triggered 5-HT release from guinea-pig colonic mucosa is mediated by the activation of 5-HT₃ receptors located at endocrine cells (enterochromaffin cells and peptide YY (PYY)-containing endocrine cells). The activation of both Y₁ and GLP-1 receptors appears to be required for the maintenance of 5-HT₃ receptor-triggered 5-HT release. It is therefore considered that 5-HT₃ receptors located at colonic mucosa play a crucial role in paracrine signaling between enterochromaffin cells and PYY-containing endocrine cells.

Efficacy and safety of 5-hydroxytryptamine 3 receptor antagonists in irritable bowel syndrome: A systematic review and meta-analysis of randomized controlled trials

AIM

We assessed the efficacy and safety of 5-hydroxytryptamine (5-HT3) receptor antagonists in adults with non-constipated irritable bowel syndrome (IBS) or diarrhea-predominant IBS (IBS-D).

METHODS

We searched PubMed, MEDLINE, EMBASE, and the Cochrane Controlled Trials Register for randomized controlled trials (RCTs) involving adults with non-constipated IBS or IBS-D that compared 5-HT3 receptor antagonists with placebo or other conventional treatment. Dichotomous symptom data were pooled to obtain the relative risk (RR) and 95% confidence intervals (CIs) for improving global IBS symptoms, abdominal pain and abnormal bowel habits, or stool consistency symptoms after therapy, and adverse events, including constipation. Meta- analysis was performed with Mantel Haenszel method using Revman 5.3 software.

RESULTS

We included 21 RCTs; 16 were high quality (Jadad score ≥ 4). The pooled RR of global IBS symptoms improved by 5-HT3 receptor antagonists versus placebo or mebeverine was 1.56 (95% CI: 1.43-1.71); alosetron, ramosetron, and cilansetron had similar treatment effects. The pooled RR of abdominal pain relieved by 5-HT3 receptor antagonists versus placebo was 1.33 (95% CI: 1.26-1.39). The pooled RR showed that 5-HT3 receptor antagonists improved abnormal bowel habits or stool consistency symptoms (RR = 1.63, 95% CI: 1.33, 1.99). The pooled RR of adverse events following 5-HT3 receptor antagonist treatment was 1.15 (95% CI: 1.08, 1.22). Subgroup analysis indicated that alosetron had a high rate of adverse effects (RR = 1.16, 95% CI: 1.08, 1.25); adverse events following ramosetron treatment were not statistically significantly different. 5-HT3 receptor antagonists were likelier to cause constipation: the pooled RR of constipation developing with 5-HT3 receptor antagonist versus placebo was 3.71 (95% CI: 2.98-4.61). However, constipation was likelier in patients with non-constipated IBS after taking 5-HT3 receptor antagonists than in patients with IBS-D only (non-constipated IBS and IBS-D: RR = 5.28 [95% CI: 3.93, 7.08] vs. IBS-D only 3.24 [2.54, 4.12]).

CONCLUSIONS

Ramosetron, cilansetron, ondansetron, and alosetron are effective for treating non-constipated IBS and IBS-D. Our systematic review found rare serious adverse events.

Current and emergent pharmacologic treatments for irritable bowel syndrome with diarrhea: evidence-based treatment in practice

Irritable bowel syndrome with diarrhea (IBS-D) is a common, chronic functional gastrointestinal disorder with symptoms that can be distressing for patients and often result in substantially impaired quality of life. This review focuses on providing clinicians with information on practical, evidence-based treatment for IBS-D. Current therapies commonly used for the treatment of IBS-D, including pharmacologic and nonpharmacologic interventions, are briefly reviewed, followed by discussion of the emergent pharmacologic treatments (rifaximin and eluxadoline) and medical foods (IBgard® and EnteraGam®). Given the lack of a standard treatment algorithm for IBS-D and the emergence of new pharmacologic therapies, treatment needs to be tailored to the individual patient and take into account the severity of disease. In this context, the latter part of this manuscript examines how treatments for IBS-D can be used in clinical practice by presenting three patient case scenarios with varying degrees of IBS-D severity. For each case, the patient's medical history and clinical presentation are related to the Rome Foundation multidimensional clinical profile (MDCP) and potential treatment options with current and emergent therapies are reviewed. The interplay of gastrointestinal symptoms and their psychosocial impact, as well as the importance of a patient-centered approach to therapy, are discussed. Consideration is given to the potential need for combination therapies and how emergent treatments could fit into the treatment pathway for mild, moderate, and severe cases of IBS-D in clinical practice.

Management of the multiple symptoms of irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders. A stepwise management approach is advocated for patients with IBS. For a substantial proportion of patients with mild symptoms, general management principles, including making a confident diagnosis and offering explanation, reassurance, and dietary and lifestyle advice, are sufficient. However, many patients continue to have moderate-to-severe symptoms and are not satisfied solely with this approach. In these patients, use of pharmacotherapy on the basis of the predominant symptom (constipation, diarrhoea, pain, or bloating) or combination of symptoms is the next step. For patients with symptoms that are refractory to these initial treatment options and those who have comorbid conditions or psychological symptoms, a combination of therapies should be used, and the use of psychotropic drugs and psychological treatment alternatives is often effective. Finally, the key to successful treatment of patients with IBS is a good physician-patient relationship and use of person-centred care principles.

Pharmacological Approach for Managing Pain in Irritable Bowel Syndrome: A Review Article

Context

Visceral pain is a leading symptom for patients with irritable bowel syndrome (IBS) that affects 10% - 20 % of the world population. Conventional pharmacological treatments to manage IBS-related visceral pain is unsatisfactory. Recently, medications have emerged to treat IBS patients by targeting the gastrointestinal (GI) tract and peripheral nerves to alleviate visceral pain while avoiding adverse effects on the central nervous system (CNS). Several investigational drugs for IBS also target the periphery with minimal CNS effects.

Evidence of Acquisition

In this paper, reputable internet databases from 1960 - 2016 were searched including Pubmed and ClinicalTrials.org, and 97 original articles analyzed. Search was performed based on the following keywords and combinations: irritable bowel syndrome, clinical trial, pain, visceral pain, narcotics, opioid, chloride channel, neuropathy, primary afferent, intestine, microbiota, gut barrier, inflammation, diarrhea, constipation, serotonin, visceral hypersensitivity, nociceptor, sensitization, hyperalgesia.

Results

Certain conventional pain managing drugs do not effectively improve IBS symptoms, including NSAIDs, acetaminophen, aspirin, and various narcotics. Anxiolytic and antidepressant drugs (Benzodiazepines, TCAs, SSRI and SNRI) can attenuate pain in IBS patients with relevant comorbidities. Clonidine, gabapentin and pregabalin can moderately improve IBS symptoms. Lubiprostone relieves constipation predominant IBS (IBS-C) while loperamide improves diarrhea predominant IBS (IBS-D). Alosetron, granisetron and ondansetron can generally treat pain in IBS-D patients, of which alosetron needs to be used with caution due to cardiovascular toxicity. The optimal drugs for managing pain in IBS-D and IBS-C appear to be eluxadoline and linaclotide, respectively, both of which target peripheral GI tract.

Conclusions

Conventional pain managing drugs are in general not suitable for treating IBS pain. Medications that target the GI tract and peripheral nerves have better therapeutic profiles by limiting adverse CNS effects.

Irritable Bowel Syndrome: Pathophysiology and Current Therapeutic Approaches

Irritable bowel syndrome (IBS) is a prevalent condition affecting 10-20% of adults in most countries; IBS results in significant morbidity and health care costs. IBS is a disorder of the brain-gut axis, and recent insights into the pathophysiological mechanisms include altered bile acid metabolism, neurohormonal regulation, immune dysfunction, alterations in the epithelial barrier, and secretory properties of the gut. There remains a significant unmet need for effective treatments, particularly for the pain component of IBS, although the introduction of drugs directed at secretion, motility, and a nonabsorbable antibiotic provides an option for the bowel dysfunction in IBS.

Regulating effect of TongXie-YaoFang on colonic epithelial secretion via Cl- and HCO3- channel

AIM

To investigate the pharmacological effect of TongXie-YaoFang (TXYF) formula, a Chinese herbal formula, on Diarrhea-predominant irritable bowel syndrome (D-IBS) rats.

METHODS

In a neonatal maternal separation plus restraint stress (NMS + RS) model of D-IBS, male Sprague Dawley rats were randomly divided into two groups (NMS + RS group and TXYF-formula group) with no handlings were used as controls (NH group). Starting from postnatal day 60, rats in TXYF-formula group were administered TXYF-formula (4.92 g/100 g bodyweight) orally twice a day for 14 consecutive days while NH group and NMS + RS group were given distilled water. Using short-circuit current technology, we observed 5-HT-induced changes of current across ion channels, such as cystic fibrosis transmembrane conductance regulator (CFTR) Cl^- channel, epithelial Na⁺ channel (ENaC), Ca²⁺-dependent Cl^- channel (CACC), Na⁺-K⁺-2Cl^- co-transporter (NKCC), and Na⁺-HCO₃^- co-transporter (NBC), in the colonic epithelium of three groups after exposure to drugs and specific blockers with a Power Lab System (AD Instruments International).

RESULTS

Under basal conditions, the changes of short-circuit current (∆Isc, µA/cm²) induced by 5-HT were similar in NH group and TXYF-formula group, and both higher than NMS + RS group (70.86 µA/cm² ± 12.32 µA/cm², 67.67 µA/cm² ± 11.68 µA/cm² vs 38.8 µA/cm² ± 7.25 µA/cm², P < 0.01, respectively). When CACC was blocked by 4,4′-diisothiocyanato-stilbene-2,2′-disulfonic acid, 5-HT-induced ∆Isc was smaller in NMS + RS group than in NH group and TXYF-formula group, respectively (48.41 µA/cm² ± 13.15 µA/cm² vs 74.62 µA/cm² ± 10.73 µA/cm², 69.22 µA/cm² ± 11.7 µA/cm², P < 0.05, respectively). The similar result could be obtained when ENaC was blocked by Amiloride (44.69 µA/cm² ± 12.58 µA/cm² vs 62.05 µA/cm² ± 11.26 µA/cm², 62.11 µA/cm² ± 12.01 µA/cm², P < 0.05, respectively). However, when CFTR Cl^- channel was blocked by 1,1-dimethyl piperidinium chloride (DPC), 5-HT-induced ∆Isc did not significantly differ in three groups (42.28 µA/cm² ± 10.61 µA/cm² vs 51.48 µA/cm² ± 6.56 µA/cm² vs 47.75 µA/cm² ± 7.99 µA/cm², P > 0.05, respectively). The similar results could also be obtained in three groups when NBC and NKCC were respectively blocked by their blockers.

CONCLUSION

TXYF-formula can regulate the Cl^- and HCO₃^- secretion of colonic mucosa via CFTR Cl^- channel, Cl^-/HCO₃^- exchanger, NBC and NKCC co-transporters.

Rifaximin for the treatment of diarrhea-predominant irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic, functional bowel disorder characterized by abdominal pain or discomfort and altered bowel habit. The pathophysiology is unclear, but may include altered gut motility, visceral hypersensitivity, abnormal central pain processing, chronic low-grade intestinal inflammation, or disturbances in the gut microbiome. These etiological mechanisms, alongside environmental factors such as stress and anxiety, vary between individuals and represent potential targets for treatment. Rifaximin is a poorly absorbed oral antibiotic proposed to act on the gut microenvironment, used in the treatment of travelers' diarrhea and hepatic encephalopathy. Clinical trials suggest the drug can reduce global IBS symptoms and improve bloating, abdominal pain, and stool consistency in some patients with non-constipated IBS, leading to Food and Drug Administration approval in the United States. This article considers the pharmacology of rifaximin, the evidence for its use in IBS, and the safety and tolerability of the drug.

The comparison of treatments with and without azithromycin in irritable bowel syndrome with diarrhea-predominant in gastrointestinal Clinic of Al-Zahra Hospital, Isfahan, Iran

BACKGROUND

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder. Recent studies suggest the importance of gut flora in the pathophysiology of it. Therefore, antibiotics have demonstrated a substantial benefit to reduce gut flora. Having few side effects, and applying one-dose per day, we studied the effect of azithromycin to treat IBS.

MATERIALS AND METHODS

One hundred and twenty-six patients enrolled a randomized, double-blind, placebo-controlled study. The treatment group received azithromycin in addition to common treatment. Patients were followed for 12 weeks. Patients completed daily diaries documenting their symptoms.

RESULTS

One hundred and thirteen patients completed the study. The onset of relief occurred significantly sooner, and duration of relief was significantly longer in azithromycin group. Movement, abdominal pain, bloating, and gas were significantly better in azithromycin group. Monthly results showed superior relief in bloating, gas, overall symptom, and overall bloating during 3 months. Significantly more patients in azithromycin group felt relief in bloating and gas and had greater consistency relief in almost all weeks.

CONCLUSION

In our study, azithromycin significantly relieved most symptoms, such as abdominal pain, bloating, and gas. Overall symptom and overall bloating were relieved significantly in more patients in the intervention group in all weeks.

IBS and IBD - separate entities or on a spectrum?

The acute phase of IBD with inflamed gut and often ulcerated mucosa is clearly different from the apparently normal mucosa characteristic of IBS. However, more detailed assessment has detected immune activation, increased gut permeability, increased mucosal serotonin availability, abnormalities of enteric nerve structure and function, and dysbiosis in gut microbiota in IBS - all features seen in IBD. Furthermore, as treatments for inflammation in IBD have become more effective it is now apparent that ∼1 in 3 patients with IBD in remission from inflammation still have persistent abnormalities of sensation, motility and gut microbiota, which might cause IBS-like symptoms. This Perspective explores the overlap between IBS and IBD and their treatments, proposing future directions for research in this stimulating area.

Advances in IBS 2016: A Review of Current and Emerging Data

Irritable bowel syndrome (IBS) is characterized by chronic intermittent abdominal pain and associated diarrhea (IBS-D), constipation (IBS-C), or both. IBS can significantly impact patient function and quality of life. The diagnosis of IBS is based on the presence of characteristic symptoms, the exclusion of concerning features, and selected tests to exclude organic diseases that can mimic IBS. The pathophysiology of IBS remains incompletely understood, and new contributing factors have been identified over the past decade. Altered gut immune activation, intestinal permeability, and the intestinal and colonic microbiome may be important factors. Poorly absorbed carbohydrates have been implicated in triggering IBS symptoms. Increasing evidence supports the benefit of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs). Although there are several randomized controlled trials of probiotics in IBS, they are typically poorly designed and have not consistently demonstrated efficacy. Until recently, there were few effective treatments for IBS-D. Data from recent clinical trials support the use of rifaximin, eluxadoline, and peppermint oil. Options for the treatment of IBS-C include lubiprostone and linaclotide.

Rotavirus and Serotonin Cross-Talk in Diarrhoea

Rotavirus (RV) has been shown to infect and stimulate secretion of serotonin from human enterochromaffin (EC) cells and to infect EC cells in the small intestine of mice. It remains to identify which intracellularly expressed viral protein(s) is responsible for this novel property and to further establish the clinical role of serotonin in RV infection. First, we found that siRNA specifically silencing NSP4 (siRNA^NSP4) significantly attenuated secretion of serotonin from Rhesus rotavirus (RRV) infected EC tumor cells compared to siRNA^VP4, siRNA^VP6 and siRNA^VP7. Second, intracellular calcium mobilization and diarrhoeal capacity from virulent and avirulent porcine viruses correlated with the capacity to release serotonin from EC tumor cells. Third, following administration of serotonin, all (10/10) infants, but no (0/8) adult mice, responded with diarrhoea. Finally, blocking of serotonin receptors using Ondansetron significantly attenuated murine RV (strain EDIM) diarrhoea in infant mice (2.9 vs 4.5 days). Ondansetron-treated mice (n = 11) had significantly (p < 0.05) less diarrhoea, lower diarrhoea severity score and lower total diarrhoea output as compared to mock-treated mice (n = 9). Similarly, Ondansetron-treated mice had better weight gain than mock-treated animals (p < 0.05). A most surprising finding was that the serotonin receptor antagonist significantly (p < 0.05) also attenuated total viral shedding. In summary, we show that intracellularly expressed NSP4 stimulates release of serotonin from human EC tumor cells and that serotonin participates in RV diarrhoea, which can be attenuated by Ondansetron.

Progress in treatment of irritable bowel syndrome

Irritable bowel syndrome is a common functional bowel disorder whose incidence has a tendency to increase year by year. At present, the pathogenesis of irritable bowel syndrome is not completely clear, and treatments are mainly symptomatic. In recent years, with the better understanding of its pathogenesis, some new drugs and treatments have been developed, such as methods of improving intestinal micro-ecology (antibiotics, fecal transplantation), mesalazine, and new drugs of improving intestinal secretion, motiligy and sensitivity, plant drugs, some of which have been applied clinically. This article will make a review of the current progress in treatment of irritable bowel syndrome.

Pharmacologic Therapies in Gastrointestinal Diseases

Several key areas in gastroenterology pharmacotherapy are rapidly evolving, including the treatment of hepatitis C virus (HCV), irritable bowel syndrome, gastroesophageal reflux disease (GERD) and peptic ulcer disease. HCV treatment has radically changed in the past 2 years and now most patients are treatment candidates and have a high likelihood of permanent cure. Pharmacotherapy is now first-line treatment for patients with moderate to severe symptoms of irritable bowel syndrome. Proton pump inhibitors (PPIs) are the mainstay of therapy in gastric and duodenal ulcers and GERD, although long-term use carries the risk of several side effects that should be considered.

Novel pharmacological therapies for irritable bowel syndrome

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.

Modern Management of Irritable Bowel Syndrome: More Than Motility

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.

Irritable Bowel Syndrome and Female Patients

Irritable bowel syndrome is probably the most common functional gastrointestinal disorder and is characterized by abdominal pain along with altered bowel function. It is a disorder of female predominance. This article focuses on how being female influences the pathophysiology, diagnosis, management, and treatment of this common disorder and discusses the evidence and important controversies related to these areas.

New and emerging therapies for the treatment of irritable bowel syndrome: an update for gastroenterologists

Irritable bowel syndrome is a functional bowel disorder with gastrointestinal symptoms (e.g. abdominal pain, straining, urgency, incomplete evacuation, nausea, and bloating) that occur alongside bowel function alterations (i.e. constipation, diarrhea, or both). Patients with irritable bowel syndrome may also experience comorbid anxiety and depression. Irritable bowel syndrome is common, with a prevalence estimated between 3% and 28%, affecting patient health and quality of life. Patients with moderate or severe irritable bowel syndrome generally seek medical care, whereas those with milder symptoms may choose self-management. Most patients with irritable bowel syndrome receive outpatient care, but irritable bowel syndrome-related hospitalizations do occur. The pathophysiology of irritable bowel syndrome is multifactorial (i.e. genetics, immune components, changes in the gut microbiota, disturbances in physiologic stress response systems, and psychosocial factors). Management of irritable bowel syndrome can include lifestyle changes, dietary interventions, counseling, psychologic medication, and agents that affect gastrointestinal motility. A number of therapies have emerged in recent years with clinical trial data demonstrating efficacy and safety for patients with irritable bowel syndrome, including agents that target gastrointestinal motility (i.e. linaclotide), gastrointestinal opioid receptors (i.e. asimadoline, eluxadoline), and gut microbiota (i.e. rifaximin). Linaclotide has been shown to significantly improve stool frequency and abdominal pain compared with placebo in constipation-predominant irritable bowel syndrome (number needed to treat, 5.1). Asimadoline shows efficacy in patients with moderate-to-severe irritable bowel syndrome-related pain. Rifaximin provided adequate relief of global irritable bowel syndrome symptoms versus placebo for a significantly greater percentage of patients with diarrhea-predominant irritable bowel syndrome (p < 0.001). Management that encompasses all aspects of irritable bowel syndrome (gastrointestinal symptoms) and comorbid psychologic symptoms (e.g. anxiety or depression) is important for improving overall patient health and well-being.

Irritable bowel syndrome: new insights into symptom mechanisms and advances in treatment

Despite being one of the most common conditions leading to gastroenterological referral, irritable bowel syndrome (IBS) is poorly understood. However, recent years have seen major advances. These include new understanding of the role of both inflammation and altered microbiota as well as the impact of dietary intolerances as illuminated by magnetic resonance imaging (MRI), which has thrown new light on IBS. This article will review new data on how excessive bile acid secretion mediates diarrhea and evidence from post infectious IBS which has shown how gut inflammation can alter gut microbiota and function. Studies of patients with inflammatory bowel disease (IBD) have also shown that even when inflammation is in remission, the altered enteric nerves and abnormal microbiota can generate IBS-like symptoms. The efficacy of the low FODMAP diet as a treatment for bloating, flatulence, and abdominal discomfort has been demonstrated by randomized controlled trials. MRI studies, which can quantify intestinal volumes, have provided new insights into how FODMAPs cause symptoms. This article will focus on these areas together with recent trials of new agents, which this author believes will alter clinical practice within the foreseeable future.

RGS proteins as targets in the treatment of intestinal inflammation and visceral pain: New insights and future perspectives

Regulators of G protein signaling (RGS) proteins provide timely termination of G protein-coupled receptor (GPCR) responses. Serving as a central control point in GPCR signaling cascades, RGS proteins are promising targets for drug development. In this review, we discuss the involvement of RGS proteins in the pathophysiology of the gastrointestinal inflammation and their potential to become a target for anti-inflammatory drugs. Specifically, we evaluate the emerging evidence for modulation of selected receptor families: opioid, cannabinoid and serotonin by RGS proteins. We discuss how the regulation of RGS protein level and activity may modulate immunological pathways involved in the development of intestinal inflammation. Finally, we propose that RGS proteins may serve as a prognostic factor for survival rate in colorectal cancer. The ideas introduced in this review set a novel conceptual framework for the utilization of RGS proteins in the treatment of gastrointestinal inflammation, a growing major concern worldwide.

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional gastrointestinal disease with a high population prevalence. The disorder can be debilitating in some patients, whereas others may have mild or moderate symptoms. The most important single risk factors are female sex, younger age and preceding gastrointestinal infections. Clinical symptoms of IBS include abdominal pain or discomfort, stool irregularities and bloating, as well as other somatic, visceral and psychiatric comorbidities. Currently, the diagnosis of IBS is based on symptoms and the exclusion of other organic diseases, and therapy includes drug treatment of the predominant symptoms, nutrition and psychotherapy. Although the underlying pathogenesis is far from understood, aetiological factors include increased epithelial hyperpermeability, dysbiosis, inflammation, visceral hypersensitivity, epigenetics and genetics, and altered brain-gut interactions. IBS considerably affects quality of life and imposes a profound burden on patients, physicians and the health-care system. The past decade has seen remarkable progress in our understanding of functional bowel disorders such as IBS that will be summarized in this Primer.

Update on the Management of Fecal Incontinence for the Gastroenterologist

Many patients with fecal incontinence respond to conservative measures based upon a careful assessment and a multimodality approach that Is within the expertise of the practicing gastroenterologist. However, there Is a need for new and effective strategies when conservative therapy fails. This article reviews established therapies for fecal incontinence, such as biofeedback, as well as new therapies that have been approved by the US Food and Drug Administration (FDA), such as sacral neuromodulation and an injectable bulking agent. Also reviewed are some of the newer approaches that have not yet been approved by the FDA or that have uncertain efficacy.

Bristol Stool Form Scale reliability and agreement decreases when determining Rome III stool form designations

BACKGROUND

Rater reproducibility of the Bristol Stool Form Scale (BSFS), which categorizes stools into one of seven types, is unknown. We sought to determine reliability and agreement by individual stool type and when responses are categorized by Rome III clinical designation as normal or abnormal (constipation or diarrhea).

METHODS

Thirty-four gastroenterology providers from three institutions rated 35 stool photographs using the BSFS. Twenty rerated the photographs.

KEY RESULTS

1190 individual stool type ratings were completed. Though only four photographs had absolute agreement (all Type 1 or Type 7), general agreement was high with 1132 (95.1%) of ratings being within one category type of the modal rating. Inter-rater and intra-rater reliability of the BSFS by individual stool type was excellent with intraclass correlations of 0.88 (95% CI: 0.86-0.90, p < 0.001) and 0.89 (95% CI: 0.86-0.91, p < 0.001), respectively. However, agreement decreased when using Rome III designations with 13 (37%) photographs having significantly diverging classifications (semi-interquartile range = 0.5). These 13 photographs were rated by the majority of raters as either type 2 vs type 3 or type 5 vs type 6 stools, representing the boundaries of normal vs abnormal stools. Inter-rater and intra-rater reliability of the BSFS by Rome III clinical categorization decreased with intraclass correlations of 0.75 (95% CI: 0.69-0.81, p < 0.001) and 0.65 (95% CI: 0.49-0.81, p < 0.001), respectively.

CONCLUSIONS & INFERENCES

The Bristol Stool Form Scale has excellent reliability and agreement when used to rate individual stool type by raters. However, BSFS reliability and agreement decreases when determining Rome III stool form categories.

Bowel Disorders

Functional bowel disorders are highly prevalent disorders found worldwide. These disorders have the potential to affect all members of society, regardless of age, gender, race, creed, color or socioeconomic status. Improving our understanding of functional bowel disorders (FBD) is critical as they impose a negative economic impact to the global health care system in addition to reducing quality of life. Research in the basic and clinical sciences during the past decade has produced new information on the epidemiology, etiology, pathophysiology, diagnosis and treatment of FBDs. These important findings created a need to revise the Rome III criteria for FBDs, last published in 2006. This manuscript classifies the FBDs into five distinct categories: irritable bowel syndrome (IBS); functional constipation (FC); functional diarrhea (FDr); functional abdominal bloating/distention (FAB/D); and unspecified FBD (U-FBD). Also included in this article is a new sixth category, opioid induced constipation (OIC) which is distinct from the functional bowel disorders (FBDs). Each disorder will first be defined, followed by sections on epidemiology, rationale for changes from prior criteria, clinical evaluation, physiologic features, psychosocial features and treatment. It is the hope of this committee that this new information will assist both clinicians and researchers in the decade to come.

The Intestinal Microenvironment and Functional Gastrointestinal Disorders

For decades, interactions between the enteric neuromuscular apparatus and the central nervous system have served as the primary focus of pathophysiological research in the functional gastrointestinal disorders. The accumulation of patient reports, as well as clinical observations, has belatedly led to an interest in the role of various luminal factors and their interactions with each other and the host in functional gastrointestinal disorders. Most prominent among these factors has been the role of food. As a consequence, while not always evidence-based, dietary interventions are enjoying a renaissance in irritable bowel syndrome management. Not surprisingly, given its exploration in many disease states, the gut microbiota has also been studied in functional gastrointestinal disorders; data remain inconclusive. Likewise, there is also a considerable body of experimental and some clinical data to link functional gastrointestinal disorders pathogenesis to disturbances in epithelial barrier integrity, abnormal entero-endocrine signaling and immune activation. These data provide growing evidence supporting the existence of micro-organic changes, particularly in subgroups of patients with functional dyspepsia and IBS. However, their exact role in the complex pathophysiology and symptom generation of functional gastrointestinal disorders needs to be further studied and elucidated particularly with longitudinal and interventional studies.

Pharmacological, Pharmacokinetic, and Pharmacogenomic Aspects of Functional Gastrointestinal Disorders

This article reviews medications commonly used for the treatment of patients with functional gastrointestinal disorders. Specifically, we review the animal models that have been validated for the study of drug effects on sensation and motility; the preclinical pharmacology, pharmacokinetics, and toxicology usually required for introduction of new drugs; the biomarkers that are validated for studies of sensation and motility endpoints with experimental medications in humans; the pharmacogenomics applied to these medications and their relevance to the FGIDs; and the pharmacology of agents that are applied or have potential for the treatment of FGIDs, including psychopharmacologic drugs.

Lessons learned--resolving the enigma of genetic factors in IBS

IBS is the most prevalent functional gastrointestinal disorder and phenotypically characterized by chronic abdominal discomfort, pain and altered defecation patterns. The pathophysiology of IBS is multifactorial, albeit with a substantial genetic component. To date, studies using various methodologies, ranging from family and twin studies to candidate gene approaches and genome-wide association studies, have identified several genetic variants in the context of IBS. Yet, despite enlarged sample sizes, increased statistical power and meta-analyses in the past 7 years, positive associations are still scarce and/or have not been reproduced. In addition, epigenetic and pharmacogenetic approaches remain in their infancy. A major hurdle is the lack of large homogenized case-control cohorts recruited according to standardized and harmonized criteria. The COST Action BM1106 GENIEUR (GENes in Irritable Bowel Syndrome Research Network EURope) has been established to address these obstacles. In this Review, the (epi)genetic working group of GENIEUR reports on the current state-of-the-art in the field, highlights fundamental flaws and pitfalls in current IBS (epi)genetic research and provides a vision on how to address and improve (epi)genetic approaches in this complex disorder in the future.