Randomised clinical trial: pregabalin vs placebo for irritable bowel syndrome

Chronic Visceral Pain: New Peripheral Mechanistic Insights and Resulting Treatments

Chronic visceral pain is one of the most common reasons for patients with gastrointestinal disorders, such as inflammatory bowel disease or disorders of brain-gut interaction, to seek medical attention. It represents a substantial burden to patients and is associated with anxiety, depression, reductions in quality of life, and impaired social functioning, as well as increased direct and indirect health care costs to society. Unfortunately, the diagnosis and treatment of chronic visceral pain is difficult, in part because our understanding of the underlying pathophysiologic basis is incomplete. In this review, we highlight recent advances in peripheral pain signaling and specific physiologic and pathophysiologic preclinical mechanisms that result in the sensitization of peripheral pain pathways. We focus on preclinical mechanisms that have been translated into treatment approaches and summarize the current evidence base for directing treatment toward these mechanisms of chronic visceral pain derived from clinical trials. The effective management of chronic visceral pain remains of critical importance for the quality of life of suffers. A deeper understanding of peripheral pain mechanisms is necessary and may provide the basis for novel therapeutic interventions.

Asociación Española de Neurogastroenterología y Motilidad (ASENEM) updated review on the management of functional abdominal pain

Functional abdominal pain is a disorder in which central and peripheral sensitization processes converge, leading to hypersensitivity and allodynia. Differential diagnosis is made with organic digestive, renal, gynecological, endocrine, or neurological diseases. Treatment should be individualized for each patient. In cases of debilitating pain, therapy combining drugs with different mechanisms of action can be initiated, while in less severe cases, therapy with a progressive introduction of drugs based on clinical response is advised. The first line includes general lifestyle advice and antispasmodic substances, like peppermint oil, anticholinergic/antimuscarinic, and calcium channels antagonists. In the second line of treatment, neuromodulating agents are added. Finally, when these measures fail, third-line treatments such as gabapentine and atypical antipsychotics are considered. Psychological interventions should be considered if specialized therapists are available to manage these disorders.

Abdominal Pain in Inflammatory Bowel Disease: An Evidence-Based, Multidisciplinary Review

Abdominal pain is one of the most common and impactful symptoms associated with inflammatory bowel disease (IBD), including both Crohn's disease and ulcerative colitis. A great deal of research has been undertaken over the past several years to improve our understanding and to optimize management of this issue. Unfortunately, there is still significant confusion about the underlying pathophysiology of abdominal pain in these conditions and the evidence underlying treatment options in this context. There is also a relative paucity of comprehensive reviews on this topic, including those that simultaneously evaluate pharmacological and nonpharmacological therapeutic options. In this review, our multidisciplinary team examines evidence for various currently available medical, surgical, and other analgesic options to manage abdominal pain in IBD.

AGA Clinical Practice Update on Evaluation and Management of Belching, Abdominal Bloating, and Distention: Expert Review

DESCRIPTION

Belching, bloating, and abdominal distention are all highly prevalent gastrointestinal symptoms and account for some of the most common reasons for patient visits to outpatient gastroenterology practices. These symptoms are often debilitating, affecting patients' quality of life, and contributing to work absenteeism. Belching and bloating differ in their pathophysiology, diagnosis, and management, and there is limited evidence available for their various treatments. Therefore, the purpose of this American Gastroenterological Association (AGA) Clinical Practice Update is to provide best practice advice based on both controlled trials and observational data for clinicians covering clinical features, diagnostics, and management considerations that include dietary, gut-directed behavioral, and drug therapies.

METHODS

This Expert Review was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the Clinical Practice Updates Committee and external peer review through standard procedures of Gastroenterology. These best practice advice statements were drawn from a review of the published literature based on clinical trials, the more robust observational studies, and from expert opinion. Because systematic reviews were not performed, these best practice advice statements do not carry formal ratings regarding the quality of evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Clinical history and physical examination findings and impedance pH monitoring can help to differentiate between gastric and supragastric belching. BEST PRACTICE ADVICE 2: Treatment options for supragastric belching may include brain-gut behavioral therapies, either separately or in combination, such as cognitive behavioral therapy, diaphragmatic breathing, speech therapy, and central neuromodulators. BEST PRACTICE ADVICE 3: Rome IV criteria should be used to diagnose primary abdominal bloating and distention. BEST PRACTICE ADVICE 4: Carbohydrate enzyme deficiencies may be ruled out with dietary restriction and/or breath testing. In a small subset of at-risk patients, small bowel aspiration and glucose- or lactulose-based hydrogen breath testing may be used to evaluate for small intestinal bacterial overgrowth. BEST PRACTICE ADVICE 5: Serologic testing may rule out celiac disease in patients with bloating and, if serologies are positive, a small bowel biopsy should be done to confirm the diagnosis. A gastroenterology dietitian should be part of the multidisciplinary approach to care for patients with celiac disease and nonceliac gluten sensitivity. BEST PRACTICE ADVICE 6: Abdominal imaging and upper endoscopy should be ordered in patients with alarm features, recent worsening symptoms, or an abnormal physical examination only. BEST PRACTICE ADVICE 7: Gastric emptying studies should not be ordered routinely for bloating and distention, but may be considered if nausea and vomiting are present. Whole gut motility and radiopaque transit studies should not be ordered unless other additional and treatment-refractory lower gastrointestinal symptoms exist to warrant testing for neuromyopathic disorders. BEST PRACTICE ADVICE 8: In patients with abdominal bloating and distention thought to be related to constipation or difficult evacuation, anorectal physiology testing is suggested to rule out a pelvic floor disorder. BEST PRACTICE ADVICE 9: When dietary modifications are needed (eg, low-fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet), a gastroenterology dietitian should preferably monitor treatment. BEST PRACTICE ADVICE 10: Probiotics should not be used to treat abdominal bloating and distention. BEST PRACTICE ADVICE 11: Biofeedback therapy may be effective for bloating and distention when a pelvic floor disorder is identified. BEST PRACTICE ADVICE 12: Central neuromodulators (eg, antidepressants) are used to treat bloating and abdominal distention by reducing visceral hypersensitivity, raising sensation threshold, and improving psychological comorbidities. BEST PRACTICE ADVICE 13: Medications used to treat constipation should be considered for treating bloating if constipation symptoms are present. BEST PRACTICE ADVICE 14: Psychological therapies, such as hypnotherapy, cognitive behavioral therapy, and other brain-gut behavior therapies may be used to treat patients with bloating and distention. BEST PRACTICE 15: Diaphragmatic breathing and central neuromodulators are used to treat abdominophrenic dyssynergia.

Managing pain in irritable bowel syndrome: current perspectives and best practice

INTRODUCTION

Irritable bowel syndrome (IBS) is characterized by chronic symptoms (>6 months) of abdominal pain in combination with a disturbed bowel habit. There is an association between the intensity of abdominal pain and the need for health care utilization. A bidirectionally disordered gut-brain interaction is central in the pathophysiology of IBS where a number of factors, gastrointestinal and non-gastrointestinal, can contribute to the illness experience. In order to treat abdominal pain in IBS, mapping these factors in a multidimensional clinical profile is helpful.

AREAS COVERED

This review covers basic epidemiology and pathophysiology of abdominal pain in IBS, the diagnostic approach, and a multidimensional treatment model where the management of abdominal pain is in focus.

EXPERT OPINION

A personalized treatment of abdominal pain in IBS is possible in patients who understand the diagnosis, the potential of therapies used, and where a good continuity in the patient-doctor relationship is established.

Update on treatment of abdominal pain in irritable bowel syndrome: A narrative review

The objectives of this narrative review are to update readers on the current state-of-the-art regarding diverse approaches for the treatment of pain, global symptoms, or adequate relief in irritable bowel syndrome (IBS). The article appraises medications, dietary interventions including low fermentable oligosaccharides, disaccharides, and monosaccharides and polyols (FODMAP) diet, fecal microbial transplantation (FMT), electrical approaches, and behavioral therapies including cognitive behavioral therapy (CBT), gut-directed hypnotherapy (GDH), mindfulness, and open-label placebo. Current evidence demonstrates only modest benefit in global IBS symptoms and pain relief. A future approach that identifies pathophysiological mechanisms of IBS through validated biomarkers has the potential to individualize treatment of patients rather than sequential therapeutic trial and error approaches.

Italian guidelines for the management of irritable bowel syndrome: Joint Consensus from the Italian Societies of: Gastroenterology and Endoscopy (SIGE), Neurogastroenterology and Motility (SINGEM), Hospital Gastroenterologists and Endoscopists (AIGO), Digestive Endoscopy (SIED), General Medicine (SIMG), Gastroenterology, Hepatology and Pediatric Nutrition (SIGENP) and Pediatrics (SIP)

The irritable bowel syndrome (IBS) is a chronic disorder of gut-brain interaction. IBS is still associated with areas of uncertainties, especially regarding the optimal diagnostic work-up and the more appropriate management. Experts from 7 Italian Societies conducted a Delphi consensus with literature summary and voting process on 27 statements. Recommendations and quality of evidence were evaluated using the grading of recommendations, assessment, development, and evaluation (GRADE) criteria. Consensus was defined as >80% agreement and reached for all statements. In terms of diagnosis, the consensus supports a positive diagnostic strategy with a symptom-based approach, including the psychological comorbidities assessment and the exclusion of alarm symptoms, together with the digital rectal examination, full blood count, C-reactive protein, serology for coeliac disease, and fecal calprotectin assessment. Colonoscopy should be recommended in patients with alarm features. Regarding treatment, the consensus strongly supports a dietary approach for patients with IBS, the use of soluble fiber, secretagogues, tricyclic antidepressants, psychologically directed therapies and, only in specific IBS subtypes, rifaximin. A conditional recommendation was achieved for probiotics, polyethylene glycol, antispasmodics, selective serotonin reuptake inhibitors and, only in specific IBS subtypes, 5-HT3 antagonists, 5-HT4 agonists, bile acid sequestrants.

Integrating mechanistic-based and classification-based concepts into perioperative pain management: an educational guide for acute pain physicians

Chronic pain begins with acute pain. Physicians tend to classify pain by duration (acute vs chronic) and mechanism (nociceptive, neuropathic and nociplastic). Although this taxonomy may facilitate diagnosis and documentation, such categories are to some degree arbitrary constructs, with significant overlap in terms of mechanisms and treatments. In clinical practice, there are myriad different definitions for chronic pain and a substantial portion of chronic pain involves mixed phenotypes. Classification of pain based on acuity and mechanisms informs management at all levels and constitutes a critical part of guidelines and treatment for chronic pain care. Yet specialty care is often siloed, with advances in understanding lagging years behind in some areas in which these developments should be at the forefront of clinical practice. For example, in perioperative pain management, enhanced recovery protocols are not standardized and tend to drive treatment without consideration of mechanisms, which in many cases may be incongruent with personalized medicine and mechanism-based treatment. In this educational document, we discuss mechanisms and classification of pain as it pertains to commonly performed surgical procedures. Our goal is to provide a clinical reference for the acute pain physician to facilitate pain management decision-making (both diagnosis and therapy) in the perioperative period.

Abdominophrenic Dyssynergia: A Narrative Review

Chronic bloating and abdominal distension are common and highly bothersome gastrointestinal symptoms. Although the differential diagnoses for bloating and distension are broad, these symptoms are frequently associated with disorders of the gut-brain interaction. Functional abdominal bloating may be a result of visceral hypersensitivity, whereas abdominal distension seems to be a somatic behavioral response associated with abdominophrenic dyssynergia, featuring diaphragmatic contraction and abdominal wall relaxation. We review the available literature regarding abdominophrenic dyssynergia and comment on its epidemiology, diagnosis, treatment, and avenues to address in the near future.

Randomized clinical trial: the effects of pregabalin for centrally mediated abdominal pain syndrome

Background

Pregabalin is worldwidely licensed for the treatment of a variety of pain syndromes and supposed to be a potential candidate for the centrally mediated abdominal pain syndrome (CAPS).

Objectives

To investigate the efficacy of pregabalin on nociceptive and emotional symptoms in CAPS patients.

Design

This is an open-label randomized controlled trial.

Methods

CAPS patients were randomized to receive pregabalin 75 mg (P group), pinaverium bromide 50 mg (PB group), or pregabalin combined pinaverium bromide regimen (P + PB group) three times daily for 4 weeks. Questionnaires were completed biweekly. The primary outcomes were defined as the average abdominal pain scores of severity and frequency at weeks 2 and 4. Secondary outcomes included the reduction in abdominal pain scores, Somatic Self-rating Scale (SSS), Patient Health Questionnaire-15 (PHQ-15), and Generalized Anxiety Disorder Scale 7 (GAD-7) scales obtained at the end of trial to the baseline.

Results

Totally, 102 eligible patients were recruited and randomized. The mean severity scores of abdominal pain were 1.39 ± 1.28, 0.97 ± 1.43 versus 2.91 ± 1.44 (p < 0.0001) in P or PB + P group versus PB group at week 2 and were 0.90 ± 1.21, 1.28 ± 1.87 versus 2.74 ± 1.75 (p < 0.0001) at week 4. The mean frequency scores were 2.55 ± 2.55, 2.03 ± 2.80 versus 5.12 ± 2.09(p < 0.0001) in P or PB + P group versus PB group at week 2 and were 1.72 ± 2.46, 2.00 ± 2.90 versus 4.55 ± 2.55 (p < 0.0001) at week 4. When comparing the changes in SSS, PHQ-15, and GAD-7 scores, patients accepting pregabalin or pregabalin combination regimen reported a more decrease than pinaverium bromide recipients (p = 0.0002, p = 0.0002, and p = 0.0033).

Conclusion

This trial suggests that pregabalin may be beneficial for CAPS abdominal pain and concomitant somatic or anxiety symptoms.

Registration

www.chictr.org.cn (ChiCTR1900028026).

Multi-omics for biomarker approaches in the diagnostic evaluation and management of abdominal pain and irritable bowel syndrome: what lies ahead

Reliable biomarkers for common disorders of gut-brain interaction characterized by abdominal pain, including irritable bowel syndrome (IBS), are critically needed to enhance care and develop individualized therapies. The dynamic and heterogeneous nature of the pathophysiological mechanisms that underlie visceral hypersensitivity have challenged successful biomarker development. Consequently, effective therapies for pain in IBS are lacking. However, recent advances in modern omics technologies offer new opportunities to acquire deep biological insights into mechanisms of pain and nociception. Newer methods for large-scale data integration of complementary omics approaches have further expanded our ability to build a holistic understanding of complex biological networks and their co-contributions to abdominal pain. Here, we review the mechanisms of visceral hypersensitivity, focusing on IBS. We discuss candidate biomarkers for pain in IBS identified through single omics studies and summarize emerging multi-omics approaches for developing novel biomarkers that may transform clinical care for patients with IBS and abdominal pain.

Functional Abdominal Cramping Pain: Expert Practical Guidance

Functional abdominal cramping pain (FACP) is a common complaint, which may present either on its own or in association with a functional gastrointestinal disorder. It is likely caused by a variety of, probably partly unknown, etiologies. Effective management of FACP can be challenging owing to the lack of usable diagnostic tools and the availability of a diverse range of treatment approaches. Practical guidance for their selection and use is limited. The objective of this article is to present a working definition of FACP based on expert consensus, and to propose practical strategies for the diagnosis and management of this condition for physicians, pharmacists, and patients. A panel of experts on functional gastrointestinal disorders was convened to participate in workshop activities aimed at defining FACP and agreeing upon a recommended sequence of diagnostic criteria and management recommendations. The key principles forming the foundation of the definition of FACP and suggested management algorithms include the primacy of cramping pain as the distinguishing symptom; the importance of recognizing and acting upon alarm signals of potential structural disease; the recognition of known causes that might be addressed through lifestyle adjustment; and the central role of antispasmodics in the treatment of FACP. The proposed algorithm is intended to assist physicians in reaching a meaningful diagnostic endpoint based on patient-reported symptoms of FACP. We also discuss how this algorithm may be adapted for use by pharmacists and patients.

Identification of bacterial lipopeptides as key players in IBS

OBJECTIVES

Clinical studies revealed that early-life adverse events contribute to the development of IBS in adulthood. The aim of our study was to investigate the relationship between prenatal stress (PS), gut microbiota and visceral hypersensitivity with a focus on bacterial lipopeptides containing γ-aminobutyric acid (GABA).

DESIGN

We developed a model of PS in mice and evaluated, in adult offspring, visceral hypersensitivity to colorectal distension (CRD), colon inflammation, barrier function and gut microbiota taxonomy. We quantified the production of lipopeptides containing GABA by mass spectrometry in a specific strain of bacteria decreased in PS, in PS mouse colons, and in faeces of patients with IBS and healthy volunteers (HVs). Finally, we assessed their effect on PS-induced visceral hypersensitivity.

RESULTS

Prenatally stressed mice of both sexes presented visceral hypersensitivity, no overt colon inflammation or barrier dysfunction but a gut microbiota dysbiosis. The dysbiosis was distinguished by a decreased abundance of Ligilactobacillus murinus, in both sexes, inversely correlated with visceral hypersensitivity to CRD in mice. An isolate from this bacterial species produced several lipopeptides containing GABA including C14AsnGABA. Interestingly, intracolonic treatment with C14AsnGABA decreased the visceral sensitivity of PS mice to CRD. The concentration of C16LeuGABA, a lipopeptide which inhibited sensory neurons activation, was decreased in faeces of patients with IBS compared with HVs.

CONCLUSION

PS impacts the gut microbiota composition and metabolic function in adulthood. The reduced capacity of the gut microbiota to produce GABA lipopeptides could be one of the mechanisms linking PS and visceral hypersensitivity in adulthood.

Practical approach to irritable bowel syndrome-diarrhea beyond low-FODMAP diet

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain and altered defecation, usually accompanied by abdominal bloating or distension. The integrated model of bidirectional interaction between the central, autonomic, enteric nervous system, the microbiome, and the gut barrier allows a better understanding of the pathophysiology of IBS, as well as consideration of potential therapeutic strategies. IBS with predominant diarrhea (IBS-D) represents a therapeutic challenge. Dietary changes or restrictions are most commonly used by patients in an attempt at symptom control. Therefore, a number of diets, especially low-FODMAP diet, have increasingly gained interest as a therapy for IBS-D or mixed IBS. However, this kind of diet, while effective, is not exempt of problems. It is therefore necessary that other therapeutic options be considered while bearing pathophysiological mechanisms and general symptom management in mind.

Comparing probiotic and drug interventions in irritable bowel syndrome: a meta-analysis of randomised controlled trials

Clinical decisions made by health professionals to recommend either drug or probiotic interventions for irritable bowel syndrome (IBS) should be supported by proper knowledge of the efficacy rates of both types of interventions. In this article, we performed a systematic review and meta-analysis to examine the efficacy of both probiotic- and drug interventions in IBS. Medline was searched between January 2015 - January 2021. Randomised controlled trials (RCT) recruiting participants > 18 years old with IBS and examining the effect of probiotics or drugs were eligible for inclusion. The data of the primary outcome, i.e. the persistence of IBS symptoms (dichotomous symptom data), were pooled to obtain a relative risk (RR), with a 95% confidence interval (CI). Secondary outcomes, abdominal pain- and bloating scores (continuous data), were pooled using a standardised mean difference with a 95% CI. The search identified 269 citations of which 32 RCTs were eligible. Our meta-analysis indicated that both probiotic and drug interventions are able to improve the persistence of IBS symptoms (RR 0.60 [0.51; 0.92] versus 0.87 [0.81; 0.92], respectively) and abdominal pain scores (standardised mean difference (SMD) -0.35 [-0.56; -0.14] versus -0.10 [-0.20; 0.00], respectively). However, determining the overall efficacy of both intervention types is inherently complex and such results should be interpreted with care, due to the large diversity of probiotic- and drug types and doses, which is also complicated by variety in IBS subtypes. Hence, as a first step, more large scale randomised double blind placebo-controlled trials focussing on a specific IBS subtype targeted with specific probiotic strains or specific pharmaceutical modalities should be executed, enabling a more proper comparison between trials.

Inadequate safety reporting in the publications of randomised clinical trials in irritable bowel syndrome: drug versus probiotic interventions

Randomised controlled clinical trials (RCTs) offer a unique opportunity to obtain controlled efficacy and safety data to support clinical decisions. However, most RCT reporting has a stronger focus on efficacy rather than safety. This study aimed to identify the safety profile of both probiotic and drug interventions in irritable bowel syndrome (IBS). In connection to this paper, an accompanying paper was published in which a meta-analysis was conducted to evaluate the efficacy of probiotic interventions compared to that of drug interventions in IBS. Together, these two studies provide a first assessment regarding the feasibility to determine a burden to benefit ratio for both probiotic and drug interventions in IBS. RCTs including participants (>18 years old) with IBS and comparing probiotic or drugs interventions with control groups were identified by a systematic search of MEDLINE (January 2015 - Jan 2021). Reported safety profiles in drug studies were completer and more detailed as compared with studies on probiotics. Several inconsistencies in safety reporting were identified between and within drug and probiotic studies, such as: didn't report on safety; only reported adverse reactions (ARs) or adverse events (AEs) with a certain severity; didn't report the total number of AEs; didn't split in the control- or experimental arm; didn't specify AEs; and used different thresholds for 'common' AEs. Hence, it is difficult to compare safety data from drug and probiotic RCTs across and between different studies. On the current approaches to safety reporting, we could not establish an unambiguous safety profile for neither probiotic and drug interventions in IBS. These shortcomings hamper a critical comparison of the burden to benefit ratio for IBS intervention.

Global Research Trends in Irritable Bowel Syndrome: A Bibliometric and Visualized Study

Background

There are about 10–23% of adults worldwide suffering from irritable bowel syndrome (IBS). Over the past few decades, there are many aspects of uncertainty regarding IBS leading to an ongoing interest in the topic as reflected by a vast number of publications, whose heterogeneity and variable quality may challenge researchers to measure their scientific impact, to identify collaborative networks, and to grasp actively researched themes. Accordingly, with help from bibliometric approaches, our goal is to assess the structure, evolution, and trends of IBS research between 2007 and 2022.

Methods

The documents exclusively focusing on IBS from 2007 to 2022 were retrieved from the Science Citation Index Expanded of the Web of Science Core Collection. The annual productivity of IBS research, and the most prolific countries or regions, authors, journals and resource-, intellectual- and knowledge-sharing in IBS research, as well as co-citation analysis of references and keywords were analyzed through Microsoft Office Excel 2019, CiteSpace, and VOSviewer.

Results

In total, 4,092 publications were reviewed. The USA led the list of countries with the most publications (1,226, 29.96%). Mayo Clinic contributed more publications than any other institution (193, 4.71%). MAGNUS SIMREN stood out as the most active and impactful scholar with the highest number of publications and the greatest betweenness centrality value. The most high-yield journal in this field was Neurogastroenterology and motility: the official journal of the European Gastrointestinal Motility Society (275, 6.72%). Gastroenterology had the most co-citations (3,721, 3.60%). Keywords with the ongoing strong citation bursts were chromogranin A, rat model, peptide YY, gut microbiota, and low-FODMAP diet, etc.

Conclusion

Through bibliometric analysis, we gleaned deep insight into the current status of literature investigating IBS for the first time. These findings will be useful to scholars interested in understanding the key information in the field, as well as identifying possible research frontiers.

Belgian consensus on irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is characterised by recurrent abdominal pain related to defaecation or associated with altered stool frequency or consistency. Despite its prevalence, major uncertainties in the diagnostic and therapeutic management persist in clinical practice.

METHODS

A Delphi consensus was conducted by 20 experts from Belgium, and consisted of literature review and voting process on 78 statements. Grading of recommendations, assessment, development and evaluation criteria were applied to evaluate the quality of evidence. Consensus was defined as > 80 % agreement.

RESULTS

Consensus was reached for 50 statements. The Belgian consensus agreed as to the multifactorial aetiology of IBS. According to the consensus abdominal discomfort also represents a cardinal symptom, while bloating and abdominal distension often coexist. IBS needs subtyping based on stool pattern. The importance of a positive diagnosis, relying on history and clinical examination is underlined, while additional testing should remain limited, except when alarm features are present. Explanation of IBS represents a crucial part of patient management. Lifestyle modification, spasmolytics and water-solube fibres are considered first-line agents. The low FODMAP diet, selected probiotics, cognitive behavioural therapy and specific treatments targeting diarrhoea and constipation are considered appropriate. There is a consensus to restrict faecal microbiota transplantation and gluten-free diet, while other treatments are strongly discouraged.

CONCLUSIONS

A panel of Belgian gastroenterologists summarised the current evidence on the aetiology, symptoms, diagnosis and treatment of IBS with attention for the specificities of the Belgian healthcare system.

Emerging therapies in the management of Irritable Bowel Syndrome (IBS)

INTRODUCTION

Irritable bowel syndrome (IBS) is a common, symptom-based disorder of chronic abdominal pain and altered bowel habits. The pathogenesis of IBS is multifactorial, leading to the potential for the development of multiple, diverse treatment strategies. This mechanistic heterogeneity also leads to the realization that available therapies are only effective in a subset of IBS suffers. Current US Food and Drug Administration (FDA) approved therapies for IBS with diarrhea (IBS-D) and IBS with constipation (IBS-C) are reviewed. Limited symptom responses and side effect experiences lead to considerable patient dissatisfaction with currently available IBS treatments. Only a small percentage of IBS patients are on prescription therapies underscoring the potential market and need for additional therapeutic options.

AREAS COVERED

: Expanding on currently available therapies, the serotonergic and endogenous opioid receptor systems continue to be a focus of future IBS treatment development. Additional novel emerging therapies include the endogenous cannabinoid system, bile acid secretion and sequestration, and exploit our enhanced understanding of visceral sensory signaling and intestinal secretomotor function.

EXPERT OPINION

While challenges remain for the future development of IBS therapies, the diverse etiologies underlying the disorder present an opportunity for novel therapies. Hence, great potential is anticipated for future IBS treatment options.

A Practical Approach to the Diagnosis and Treatment of Abdominal Bloating and Distension

Abdominal bloating and distension are highly prevalent symptoms that can negatively impact quality of life and lead to medical consultation. Despite their prevalence, symptoms of bloating and distension pose a unique diagnostic and therapeutic challenge, as they are inherently nonspecific symptoms with a complex etiology, and no uniform diagnostic or treatment algorithm currently exists. Additionally, bloating is common among disorders of gut-brain interaction, which can be difficult to treat. This article offers a practical approach for evaluating and treating symptoms of bloating and distension through discussion of 5 common etiologies: diet, small intestinal bacterial over-growth, constipation, visceral hypersensitivity, and abdomino-phrenic dyssynergia. An effective personalized evaluation and treatment plan can be established to address symptoms of bloating and distension through consideration of these etiologies in the context of the patient's individual characteristics and presentation.

Neurotransmitter and Intestinal Interactions: Focus on the Microbiota-Gut-Brain Axis in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder of unknown etiology. IBS is caused by a disruption in the gut-brain axis. Given the importance of the gut microbiota in maintaining local and systemic homeostasis of immunity, endocrine, and other physiological processes, the microbiota-gut-brain axis has been proposed as a key regulator in IBS. Neurotransmitters have been shown to affect blood flow regulation, intestinal motility, nutrient absorption, the gastrointestinal immune system, and the microbiota in recent studies. It has the potential role to play a function in the pathophysiology of the gastrointestinal and neurological systems. Transmitters and their receptors, including 5-hydroxytryptamine, dopamine, γ-aminobutyric acid, and histamine, play an important role in IBS, especially in visceral sensitivity and gastrointestinal motility. Studies in this field have shed light on revealing the mechanism by which neurotransmitters act in the pathogenesis of IBS and discovering new therapeutic strategies based on traditional pharmacological approaches that target the nervous system or novel therapies that target the microbiota.

Oral and parenteral anti-neuropathic agents for the management of pain and discomfort in irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a highly prevalent and economically burdensome condition; and pain is often the most unpleasant, disruptive, and difficult-to-treat symptom. Visceral hypersensitivity is a common feature driving pain in IBS, suggesting that neuropathic mechanisms may be implicated. We conducted a systematic review of available evidence to examine the role of anti-neuropathic medicines in the management of pain in IBS.

METHODS

We systematically searched scientific repositories for trials investigating conventional oral, and/or parenteral, pharmaceutical antineuropathic treatments in patients with IBS. We summarized key participant characteristics, outcomes related to pain (primary outcome), and selected secondary outcomes.

KEY RESULTS

We included 13 studies (n = 629 participants): six investigated amitriptyline, three duloxetine, three pregabalin, and one gabapentin. There was considerable methodological and statistical heterogeneity, so we performed a narrative synthesis and limited meta-analysis. Amitriptyline was most extensively studied, though only in diarrhea-predominant patients. In individual trials, amitriptyline, pregabalin and gabapentin generally appeared beneficial for pain outcomes. While duloxetine studies tended to report improvements in pain, all were un-controlled trials with high risk of bias. Meta-analysis of three studies (n = 278) yielded a pooled relative-risk of 0.50 (95%CI 0.38-0.66) for not improving with anti-neuropathic agent vs control. We did not identify any eligible studies investigating the role of parenteral anti-neuropathics.

CONCLUSIONS AND INFERENCES

Anti-neuropathic analgesics may improve pain in IBS, and deserve further, high-quality investigation, potentially considering parenteral administration and agents with minimal gastrointestinal motility effects. Investigation of amitriptyline's efficacy in non-diarrhea-predominant subtypes is currently lacking, and we recommend particular caution for its use in IBS-C.

Pain in irritable bowel syndrome: Does anything really help?

Pain relief remains a significant challenge in the management of irritable bowel syndrome (IBS): "Does anything really help relieve the pain in patients with IBS?". Interventions aimed at pain relief in patients with IBS include diet, probiotics or antibiotics, antidepressants, antispasmodics, and drugs targeting specific gastrointestinal receptors such as opioid or histamine receptors. In the systematic review and meta-analysis published in this journal, Lambarth et al. examined the literature on the role of oral and parenteral anti-neuropathic agents in the management of pain in patients with IBS. This review article appraises their assessment of the efficacy of the anti-neuropathic agents amitriptyline, pregabalin, gabapentin, and duloxetine in the relief of abdominal pain or discomfort, and impact on overall IBS severity and quality of life. This commentary provides an update of current evidence on the efficacy of the dietary and pharmacological treatments that are available or in development, as well psychological and cognitive behavioral therapy for pain in IBS. Advances in recent years augur well for efficacious treatments that may expand the therapeutic arsenal for pain in IBS.

Anti-inflammatory effect of pregabalin on acetic acid-induced colitis in the rats

Background and purpose:

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease characterized by the inflammation of the intestine. The available medicinal treatments for IBD are not efficacious enough since they exert various adverse effects. Therefore, the search for new therapeutic agents should be continued. The present study aimed to assess the anti-inflammatory effects of pregabalin on acetic acid-induced colitis in rats.

Experimental approach:

Using 2 mL of 3% acetic acid solution, colitis was intra-rectally induced in rats. Animals were randomly divided into 6 groups including the normal group, colitis control group, pregabalin treatment groups (30, 50, and 100 mg/kg; i.p., respectively), and dexamethasone treatment group (1 mg/kg; i.p.). Macroscopic, microscopic, and biochemical (myeloperoxidase, tumor necrosis factor-alpha, interleukin-6, and interleukin-1 beta) examinations were used to evaluate the efficacy of pregabalin in the inflamed colon.

Findings/Results:

All the applied doses of pregabalin significantly decreased the severity of macroscopic and microscopic colonic damages including ulcer severity, ulcer area, percentage of necrosis, and total colitis index compared to the colitis control group. These results were confirmed by the reduced colonic concentration of tumor necrosis factor-alpha, interleukin-6, interleukin-1 beta, and myeloperoxidase activity.

Conclusion and implications:

Results of this study indicated that pregabalin administration has beneficial effects upon the treatment of experimental colitis, which might be partly due to its anti-inflammatory properties.

Review article: current and future treatment approaches for pain in IBS

BACKGROUND

Abdominal pain is a core symptom of IBS and a primary driver of care seeking. Visceral hypersensitivity is a key pathophysiological mechanism and therapeutic target for pain in IBS, with components of peripheral and central sensitisation and psychological factors.

AIM

To review current and future treatment approaches specifically for the pain component of IBS.

METHODS

Pubmed search terms included combinations of irritable bowel, pain, visceral hypersensitivity, novel, new, emerging, future and advances.

RESULTS

Established non-pharmacological treatments for IBS pain include the low FODMAP diet, probiotics and psychological interventions, especially hypnotherapy. Tricyclics remain the best evidenced pharmacological approach with GCC agonists, tenapanor, lubiprostone, eluxadoline and 5HT3 antagonists second line according to patient characteristics and availability. Less well-evidenced current options include anti-spasmodics, peppermint oil, SSRIs, SNRIs, alpha 2 delta ligands, melatonin and histamine antagonists. Patients are vulnerable to iatrogenesis and harmful approaches to be avoided include opioids and unwarranted surgical interventions. For severe pain, the concept of augmentation with combined gut-brain neuromodulators and psychotherapy in a multi-disciplinary setting is considered. A plethora of molecular targets and ligands are emerging from pre-clinical studies, together with early clinical evidence for a range of pharmacological, dietary, neurostimulation and novel psychological treatment delivery methods which are reviewed. The history of such emerging approaches, however, merits both caution and optimism in equal measure.

CONCLUSIONS

Despite good in-roads and emerging options, the management of abdominal pain remains one of the biggest challenges and research priorities for patients with IBS.

Targeting the Gut Microbiota to Relieve the Symptoms of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common, chronic, functional disorder with a large impact on world population. Its pathophysiology is not completely revealed; however, it is certain that dysregulation of the bidirectional communications between the central nervous system (CNS) and the gut leads to motility disturbances, visceral hypersensitivity, and altered CNS processing characterized by differences in brain structure, connectivity and functional responsiveness. Emerging evidence suggests that gut microbiota exerts a marked influence on the host during health and disease. Gut microbiome disturbances can be also important for development of IBS symptoms and its modulation efficiently contributes to the therapy. In this work, we review the current knowledge about the IBS therapy, the role of gut microbiota in pathogenesis of IBS, and we discuss that its targeting may have significant impact on the effectiveness of IBS therapy.

Development of Physiologically Based Pharmacokinetic Model for Pregabalin to Predict the Pharmacokinetics in Pediatric Patients with Renal Impairment and Adjust Dosage Regimens: PBPK Model of Pregabalin in Pediatric Patients with Renal Impairment

Pregabalin (PGB) is widely used clinically; however, its pharmacokinetics (PK) has not been studied in pediatric patients with renal impairment (RI). To design optimized PGB regimens for pediatric patients with varying degrees of RI and predict exposure to PGB, physiologically based pharmacokinetic (PBPK) models of PGB were developed and verified, and its disposition was simulated in the healthy population and adults with RI. The simulated results from the PBPK models after single-dose and multi-dose administrations of PGB were consistent with the corresponding observed data based on the fold error values of less than 2. The area under curve ratios were 1.23 ± 0.06, 2.02 ± 0.10, 3.86 ± 0.21, and 9.92 ± 0.79 in pediatric patients with mild, moderate, severe, and end-stage RI, respectively. Based on the predictions for pediatric patients with moderate, severe, and end-stage RI, the maximum dose should not exceed 7, 3.5, and 1.4 mg/kg/day, respectively, among those weighing < 30 kg, and it should not exceed 5, 2.5, and 1 mg/kg/day, respectively, among those weighing > 30 kg. In conclusion, the developed PBPK model is a valuable tool for predicting PGB dosage for pediatric patients with RI.

Randomised clinical trial: the effects of pregabalin vs placebo on functional dyspepsia

BACKGROUND

Currently, central neuromodulators are among the therapeutic options for the treatment of functional dyspepsia (FD). Pregabalin, a gabapentinoid, is a neuromodulator that could potentially improve visceral hypersensitivity in FD patients.

AIM

To assess the efficacy and safety of pregabalin for the treatment of FD METHODS: We performed a randomised placebo-controlled study including FD patients who did not respond to proton pump inhibitors. Patients were randomly assigned to receive pregabalin (75 mg daily) or placebo for 8 weeks. The primary outcome was an adequate relief response rate. The secondary outcomes were improvement in quality of life, pain scores in divided categories, and safety profile.

RESULTS

Of 72 patients enrolled, 34 received pregabalin and 38 received placebo. The self-reported adequate relief rates in the pregabalin and placebo groups were 70.6% and 42.1% at week 4 (P = 0.02), and 70.6% and 44.7% at week 8 (P = 0.03), respectively. The reduction in global symptoms in the pregabalin and placebo groups were 11.7 ± 10.6 and 3.7 ± 8.9 points at week 4 (P < 0.01) and 15.1 ± 12.2 and 8.0 ± 10.2 points at week 8 (P = 0.01), respectively. Pregabalin improved the overall quality of life (P = 0.03). The most common adverse event with pregabalin was dizziness, occurring in 51.6% of patients.

CONCLUSIONS

Pregabalin led to significant alleviation of dyspeptic symptoms, especially in patients with predominant epigastric pain . Thaiclinicaltrials.org #TCTR20200404002.

Medical Therapies for Diarrhea-Predominant Irritable Bowel Syndrome

Diarrhea-predominant irritable bowel syndrome is a common functional gastrointestinal disorder that manifests with abdominal pain and diarrheal bowel patterns, without structural explanation. Diarrhea-predominant irritable bowel syndrome is a heterogeneous condition resulting from diverse pathophysiologic processes. Treatment strategies with varied mechanisms of action are beneficial in its management. The clinician must become familiar with a multi-dimensional approach to irritable bowel syndrome. The 3 approved medications are central to disease management. Effective treatment uses off-label medications and emerging therapies and a growing number of over-the-counter and supplemental agents to optimize symptom improvement for the patient with diarrhea-predominant irritable bowel syndrome.

Psychopharmacologic Therapies for Irritable Bowel Syndrome

Psychopharmacologic therapies are beneficial in reducing symptoms when treating irritable bowel syndrome (IBS) and other disorders of gut-brain interaction (DGBI). Noradrenaline, serotonin, and dopamine are neurotransmitters of key importance in psychopharmacology and pain-reduction mechanisms. The first-line (tricyclic antidepressants, serotonin noradrenaline reuptake inhibitors, selective serotonin reuptake inhibitors) and second-line (atypical antipsychotics, delta-ligand agents, low-dose naltrexone) neuromodulator treatment options are recommended when IBS-associated abdominal pain is of moderate or severe intensity and is persistent. To understand the implementation strategy, the multidimensional clinical profile as a template is used for presenting 3 case scenarios involving painful IBS and DGBI of varying complexity.

Neurotransmitter Dysfunction in Irritable Bowel Syndrome: Emerging Approaches for Management

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder whose aetiology is still unknown. Most hypotheses point out the gut-brain axis as a key factor for IBS. The axis is composed of different anatomic and functional structures intercommunicated through neurotransmitters. However, the implications of key neurotransmitters such as norepinephrine, serotonin, glutamate, GABA or acetylcholine in IBS are poorly studied. The aim of this review is to evaluate the current evidence about neurotransmitter dysfunction in IBS and explore the potential therapeutic approaches. IBS patients with altered colorectal motility show augmented norepinephrine and acetylcholine levels in plasma and an increased sensitivity of central serotonin receptors. A decrease of colonic mucosal serotonin transporter and a downregulation of α2 adrenoceptors are also correlated with visceral hypersensitivity and an increase of 5-hydroxyindole acetic acid levels, enhanced expression of high affinity choline transporter and lower levels of GABA. Given these neurotransmitter dysfunctions, novel pharmacological approaches such as 5-HT₃ receptor antagonists and 5-HT₄ receptor agonists are being explored for IBS management, for their antiemetic and prokinetic effects. GABA-analogous medications are being considered to reduce visceral pain. Moreover, agonists and antagonists of muscarinic receptors are under clinical trials. Targeting neurotransmitter dysfunction could provide promising new approaches for IBS management.

British Society of Gastroenterology guidelines on the management of irritable bowel syndrome

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.

The placebo response rate in pharmacological trials in patients with irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

Clinical trials in irritable bowel syndrome are associated with high placebo response rates. We aimed to identify the magnitude of the placebo response and the contributing factors to this occurrence.

METHODS

We did a systematic review and meta-analysis with a search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials between April 1, 1959, and April 30, 2020. We included all randomised controlled trials that compared an active pharmacotherapeutic agent with placebo and had a dichotomous outcome of response to therapy (in terms of global improvement or improvement in abdominal pain) in adults (aged ≥18 years) with irritable bowel syndrome. Exclusion criteria were trials reporting on treatment satisfaction as a dichotomous outcome of response to therapy or clinician-reported outcomes and a treatment duration of less than 4 weeks. Our main outcome was identification of the magnitude of the pooled placebo response rate for the following endpoints: global improvement, abdominal pain, and US Food and Drug Administration (FDA) endpoints. We extracted information from published reports and pooled proportions through meta-analysis with random effects. The study was registered with PROSPERO, CRD42020170908.

FINDINGS

Of the 6863 publications identified, 70 articles describing 73 randomised controlled trials were included in our analysis. The pooled placebo response rate was 27·3% (95% CI 24·3-30·9) using the global improvement endpoint, 34·4% (31·2-37·8) using the abdominal pain endpoint, and 17·9% (15·2-21·0) using the composite FDA endpoint responder definition, all with substantial heterogeneity between the trials. Studies published before 2006, and those done in Europe, with a parallel design, a run-in period of 2 weeks or less, a dose schedule of three times a day or more, or a smaller sample size of the control group were significantly associated with an increased pooled placebo response rate.

INTERPRETATION

More than a quarter of patients with irritable bowel syndrome had a placebo response in terms of global improvement, with multiple associated moderators. We recommend future trials apply a run-in period of at least 2 weeks and dose once or twice a day to minimise the placebo response rate.

FUNDING

None.

Management of functional gastrointestinal disorders

Functional gastrointestinal (GI) disorders (eg irritable bowel syndrome and functional dyspepsia) are very common conditions which are associated with very poor quality of life and high healthcare utilisation. They are caused by disorders of GI functioning, namely altered gut sensitivity, motility, microbiota, immune functioning and central nervous system processing. They cause chronic symptoms throughout the gut (eg pain, dyspepsia and altered bowel habit), all of which are made worse by maladaptive patient behaviours, stress and psychological comorbidity. Management involves a biopsychosocial approach involving changes in lifestyle and diet, addressing coexisting psychological comorbidity and using medication to treat underlying pathophysiology. Pharmacological treatment with antispasmodics, neuromodulators, motility agents and antidepressants is effective. Psychotherapy in motivated individuals is equally effective. Success of treatment is increased by a good doctor-patient relationship and so this needs to be taken into account during the consultation.

Dual-trajectories of opioid and gabapentinoid use and risk of subsequent drug overdose among Medicare beneficiaries in the United States: a retrospective cohort study

BACKGROUND AND AIMS

Little is known about opioid and gabapentinoid (OPI-GABA) use duration and dose patterns' associations with adverse outcome risks. We examined associations between OPI-GABA dose and duration trajectories and subsequent drug overdose.

DESIGN

Retrospective cohort study.

SETTING

US Medicare.

PARTICIPANTS

Using a 5% sample (2011-16), we identified 71 005 fee-for-service Medicare beneficiaries with fibromyalgia, low back pain, neuropathy and/or osteoarthritis initiating OPIs and/or GABAs [mean age ± standard deviation (SD) = 65.5 ± 14.5 years, female = 68.1%, white = 76.8%].

MEASUREMENTS

Group-based multi-trajectory models identified distinct OPI-GABA use patterns during the year of OPI and/or GABA initiation, based on weekly average standardized daily dose (i.e. OPIs = morphine milligram equivalent, GABAs = minimum effective daily dose). We estimated models with three to 12 trajectories and selected the best model based on Bayesian information criterion (BIC) and Nagin's criteria. We estimated risk of time to first drug overdose diagnosis within 12 months following the index year, adjusting for socio-demographic and health factors using inverse probability of treatment weighted multivariable Cox proportional hazards models.

FINDINGS

We identified 10 distinct trajectories (BIC = -1 176 954; OPI-only = 3, GABA-only = 3, OPI-GABA = 4). Compared with OPI-only early discontinuers (40.6% of the cohort), 1-year drug overdose risk varied by trajectory group: consistent low-dose OPI-only users [16.6%; hazard ratio (HR) = 1.47, 95% confidence interval (CI) = 1.19-1.82], consistent high-dose OPI-only users (1.8%; HR = 4.57, 95% CI = 2.99-6.98), GABA-only early discontinuers (12.5%; HR = 1.39, 95% CI = 1.09-1.77), consistent low-dose GABA-only users (11.0%; HR = 1.44, 95% CI = 1.12-1.85), consistent high-dose GABA-only users (3.1%; HR = 1.43, 95% CI = 0.94-2.17), early discontinuation of OPIs and consistent low-dose GABA users (6.9%; HR = 1.24, 95% CI = 0.90-1.69), consistent low-dose OPI-GABA users (3.4%; HR = 2.49, 95% CI = 1.76-3.52), consistent low-dose OPI and high-dose GABA users (3.2%; HR = 2.46, 95% CI = 1.71-3.53) and consistent high-dose OPI and moderate-dose GABA users (0.9%; HR = 7.22, 95% CI = 4.46-11.69).

CONCLUSIONS

Risk of drug overdose varied substantially among US Medicare beneficiaries on different use trajectories of opioids and gabapentinoids. High-dose opioid-only users and all consistent opioid and gabapentinoid users (regardless of doses) had more than double the risk of subsequent drug overdose compared with opioid-only early discontinuers.

Beyond Amitriptyline: A Pediatric and Adolescent Oriented Narrative Review of the Analgesic Properties of Psychotropic Medications for the Treatment of Complex Pain and Headache Disorders

Children and adolescents with recurrent or chronic pain and headache are a complex and heterogenous population. Patients are best served by multi-specialty, multidisciplinary teams to assess and create tailored, individualized pain treatment and rehabilitation plans. Due to the complex nature of pain, generalizing pharmacologic treatment recommendations in children with recurrent or chronic pains is challenging. This is particularly true of complicated patients with co-existing painful and psychiatric conditions. There is an unfortunate dearth of evidence to support many pharmacologic therapies to treat children with chronic pain and headache. This narrative review hopes to supplement the available treatment options for this complex population by reviewing the pediatric and adult literature for analgesic properties of medications that also have psychiatric indication. The medications reviewed belong to medication classes typically described as antidepressants, alpha 2 delta ligands, mood stabilizers, anti-psychotics, anti-sympathetic agents, and stimulants.

Irritable bowel syndrome

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.

Efficacy of psychological therapies for irritable bowel syndrome: systematic review and network meta-analysis

OBJECTIVES

National guidelines for the management of irritable bowel syndrome (IBS) recommend that psychological therapies should be considered, but their relative efficacy is unknown, because there have been few head-to-head trials. We performed a systematic review and network meta-analysis to try to resolve this uncertainty.

DESIGN

We searched the medical literature through January 2020 for randomised controlled trials (RCTs) assessing efficacy of psychological therapies for adults with IBS, compared with each other, or a control intervention. Trials reported a dichotomous assessment of symptom status after completion of therapy. We pooled data using a random effects model. Efficacy was reported as a pooled relative risk (RR) of remaining symptomatic, with a 95% CI to summarise efficacy of each comparison tested, and ranked by therapy according to P score.

RESULTS

We identified 41 eligible RCTs, containing 4072 participants. After completion of therapy, the psychological interventions with the largest numbers of trials, and patients recruited, demonstrating efficacy included self-administered or minimal contact cognitive behavioural therapy (CBT) (RR 0.61; 95% CI 0.45 to 0.83, P score 0.66), face-to-face CBT (RR 0.62; 95% CI 0.48 to 0.80, P score 0.65) and gut-directed hypnotherapy (RR 0.67; 95% CI 0.49 to 0.91, P score 0.57). After completion of therapy, among trials recruiting only patients with refractory symptoms, group CBT and gut-directed hypnotherapy were more efficacious than either education and/or support or routine care, and CBT via the telephone, contingency management, CBT via the internet and dynamic psychotherapy were all superior to routine care. Risk of bias of trials was high, with evidence of funnel plot asymmetry; the efficacy of psychological therapies is therefore likely to have been overestimated.

CONCLUSIONS

Several psychological therapies are efficacious for IBS, although none were superior to another. CBT-based interventions and gut-directed hypnotherapy had the largest evidence base and were the most efficacious long term.

TRIAL REGISTRATION NUMBER

The study protocol was published on the PROSPERO international prospective register of systematic reviews (registration number CRD 42020163246).

An update on efficacy and safety considerations for the latest drugs used to treat irritable bowel syndrome

INTRODUCTION

Irritable bowel syndrome (IBS), globally affecting 11.2% of the population and imposing a direct annual cost of $1.7bn-$10bn in the US, is one of the today's major therapeutic challenges. Therefore, there is urgent need to address this issue through reviewing the tolerability and efficacy of available medications.

AREAS COVERED

Over the past decade, related experiments were cited through Clinicaltrials.gov, PubMed, WHO ICTRP, and Cochrane library. Pharmacological parameters of approved medications available in the USFDA, EMA, TGA and PMDA were also stated.

EXPERT OPINION

Anti-spasmodics are used as the first-line treatment in pain-predominant IBS and IBS-D, among which calcium channel blockers and neurokinin-type 2 receptor antagonists seem to replace anti-cholinergic drugs. As second-line treatments, rifaximin is considered to be the best for IBS-D though it has lower efficacy than alosetron and eluxadoline. For IBS-C, linaclotide is the most effective and the safest second-line therapy, following laxatives/fibers, which may be replaced by tenapanor, in the future. When moderate to severe IBS is associated with severe pain or comorbid psychological disorders, gut-brain neuromodulators could also be prescribed. Regarding all this, there is still a paramount need to conduct careful clinical studies on efficacy, safety and cost-effectiveness of current approved and non-approved treatments.

Mirogabalin prevents repeated restraint stress-induced dysfunction in mice

Gabapentinoids, which are the common analgesics, are also thought to be an effective treatment for anxiety disorder, which is one of several psychiatric disorders triggered and exacerbated by stress. The aim of the present study was to investigate whether mirogabalin, a recently launched gabapentinoid, protects multiple brain functions against repeated restraint stress. Adult male ddY mice were restrained for 7 days (repeated restraint stress: 2 h/day) or for 30 min (single restraint stress). Mirogabalin (intraperitoneal, intracerebroventricular or intrahippocampal injection) was administered prior to the restraint stress. Y-maze, elevated-plus maze and c-Fos immunohistochemistry were performed to evaluate learning function, anxiety levels and hippocampal neuronal activities, respectively, after the 7th day of the repeated restraint stress. Intestinal function was evaluated in terms of defecation, which was scored after the 5th day of repeated restraint stress and by the number of fecal pellets excreted after a single session of restraint stress. Repeated restraint stress induced memory dysfunction, anxiety-like behavior, an abnormal defecation score and increased hippocampal c-Fos expression. These changes were prevented by systemic administration of mirogabalin. Abnormal defecation was also induced by single restraint stress, and was inhibited by both systemic and central administration of mirogabalin, suggesting that the effect on the intestinal function was also mediated via the central nervous system. Enhancement of c-Fos expression by repeated stress was decreased by intrahippocampal injection of mirogabalin. Together, these observations suggest that mirogabalin protects multiple brain functions from repeated stress, which may be mediated by inhibition of hippocampal neuron hyperactivation.

Gastrointestinal pain

Gastrointestinal (GI) pain - a form of visceral pain - is common in some disorders, such as irritable bowel syndrome, Crohn's disease and pancreatitis. However, identifying the cause of GI pain frequently represents a diagnostic challenge as the clinical presentation is often blurred by concomitant autonomic and somatic symptoms. In addition, GI pain can be nociceptive, neuropathic and associated with cancer, but in many cases multiple aetiologies coexist in an individual patient. Mechanisms of GI pain are complex and include both peripheral and central sensitization and the involvement of the autonomic nervous system, which has a role in generating the symptoms that frequently accompany pain. Treatment of GI pain depends on the precise type of pain and the primary disorder in the patient but can include, for example, pharmacological therapy, cognitive behavioural therapies, invasive surgical procedures, endoscopic procedures and lifestyle alterations. Owing to the major differences between organ involvement, disease mechanisms and individual factors, treatment always needs to be personalized and some data suggest that phenotyping and subsequent individual management of GI pain might be options in the future.