Safety and tolerability of rifaximin for the treatment of irritable bowel syndrome without constipation: a pooled analysis of randomised, double-blind, placebo-controlled trials

Microbiota modulation in disorders of gut-brain interaction

Disorders of gut-brain interaction (DGBI) are common chronic conditions characterized by persistent and recurring gastrointestinal symptoms triggered by several pathophysiological factors, including an altered gut microbiota. The most common DGBI are irritable bowel syndrome (IBS), functional constipation (FC) and functional dyspepsia (FD). Recently, a deep understanding of the role of the gut microbiota in these diseases was possible due to multi-omics methods capable to provide a comprehensive assessment. Most of the therapies recommended for these patients, can modulate the gut microbiota such as diet, prebiotics, probiotics and non-absorbable antibiotics, which were shown to be safe and effective. Since patients complain symptoms after food ingestion, diet represents the first line therapeutic approach. Avoiding dietary fat and fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, and increasing the number of soluble fibers represent the therapeutic choices for FD, IBS and FC respectively. Probiotics, as a category, have been employed with good results in all the abovementioned DGBI. Rifaximin has been shown to be useful in the context of bowel related disorders, although a recent trial showed positive results for FD. Fecal microbiota transplantation has been tested for IBS and FC with promising results. In this review, we will briefly summarize the current understanding on dysbiosis and discuss microbiota modulation strategies to treat patients with DGBI.

Pharmacokinetic considerations for drugs that treat diarrhea-predominant irritable bowel syndrome: what's new?

INTRODUCTION

Irritable bowel syndrome (IBS), which presents a significant healthcare and socioeconomic burden, is one of the main issues in the field of therapy. Hence, it is imperative to tackle this matter by evaluating the safety and efficacy of the available treatments and determining the ideal approach for each patient.

AREAS COVERED

We reviewed the pharmacokinetics and safety of pharmacologic interventions administered in diarrhea-predominant IBS (IBS-D) patients. PubMed, Google Scholar and the USFDA databases were searched up to November 2023 to include all updated information on eluxadoline, alosetron, and rifaximin.

EXPERT OPINION

The most effective way to treat IBS-D is to focus on managing the most common symptoms. However, healthcare providers face a challenge when it comes to identifying the right treatment for each patient, and the root cause of this is the diversity of IBS-D population. Studies have shown that there are differences in how men and women metabolize drugs, which may lead to gender-specific adverse reactions. Women tend to have higher drug concentrations in their bloodstream and take longer to eliminate them. Therefore, healthcare providers may need to reduce the dosage for female patients. Integrating IBS care into sustainable development efforts can indirectly contribute to achieving SDGs and promote health and well-being for all.

Journal of Clinical Gastroenterology Lectureship Dubai 2022 : Management of Irritable Bowel Syndrome With Diarrhea

Irritable bowel syndrome (IBS) with diarrhea (IBS-D) affects ~1% of the general population and is characterized by abdominal pain associated with diarrhea. IBS-D symptoms significantly impact the quality of life of patients. Major uncertainties remain regarding the optimal management of these patients. Several therapies have been investigated over the years for the treatment of IBS-D. In the initial management, commonly prescribed approaches with an effect on global IBS symptoms include a low Fermentable Oligo-, Di-, Mono-Saccharides and Polyols diet and probiotics, while antispasmodics are used for targeting abdominal pain and loperamide for diarrhea only. Additional therapeutic options for the relief of global IBS symptoms include rifaximin, 5-HT 3 antagonists, gut-directed psychological therapies, and eluxadoline, while tricyclic antidepressants can target abdominal pain and bile acid sequestrants diarrhea. Promising evidence exists for the use of mesalazine and fecal microbiota transplantation in IBS-D, although further evidence is needed for definitive conclusions regarding their efficacy.

Rifaximin Treatment of Collagenous Colitis: A Randomised, Double-Blind, Placebo-Controlled Trial

Introduction

Collagenous colitis (CC) is a disabling disease primarily affecting elderly women. Sparse, well-documented treatment modalities exist, except for budesonide. Long-term and repetitive treatment with budesonide is often necessary. Rifaximin is a poorly absorbed antibiotic with a positive modulatory effect on gut microbiota. In this randomised, double-blind, placebo-controlled single-centre trial, we test the effect of adding rifaximin in continuation to budesonide on relapse rates in CC.

Methods

Eligible patients with active, biopsy-verified CC received oral budesonide during a 6-week open-label induction phase. Patients in clinical remission after 4 weeks of treatment were randomised to receive either rifaximin or placebo for 4 weeks.

Results

Fifteen patients were randomised to receive either rifaximin (n = 7) or placebo (n = 8). At 12-week follow-up, 2 patients in the rifaximin group were still in remission and none in the placebo group (p = 0.2). The median number of days in remission in the rifaximin group was 42 (interquartile range [IQR] 33-126) compared to 18.5 (IQR 10.5-51.5) in the placebo group (p = 0.189). At 12-week follow-up, the relapse rate per 100 person-days in the placebo group was higher (3.25 [1.40-6.41]) than in the rifaximin group (1.33 [0.43-3.10]).

Conclusion

Although not statistically significant (p = 0.0996), the study suggests a potential improvement in relapse rates within the rifaximin group compared to the placebo group. A major limitation in the study is the small sample size.

Gastrointestinal disorders in post-COVID syndrome. Clinical guidelines

Summary Post- COVID syndrome refers to the long-term consequences of a new coronavirus infection COVID-19, which includes a set of symptoms that develop or persist after COVID-19. Symptoms of gastrointestinal disorders in post- COVID syndrome, due to chronic infl ammation, the consequences of organ damage, prolonged hospitalization, social isolation, and other causes, can be persistent and require a multidisciplinary approach. The presented clinical practice guidelines consider the main preventive and therapeutic and diagnostic approaches to the management of patients with gastroenterological manifestations of postCOVID syndrome. The Guidelines were approved by the 17th National Congress of Internal Medicine and the 25th Congress of Gastroenterological Scientifi c Society of Russia.

Diverticular Disease and Rifaximin: An Evidence-Based Review

There have been considerable advances in the treatment of diverticular disease in recent years. Antibiotics are frequently used to treat symptoms and prevent complications. Rifaximin, a non-absorbable antibiotic, is a common therapeutic choice for symptomatic diverticular disease in various countries, including Italy. Because of its low systemic absorption and high concentration in stools, it is an excellent medicine for targeting the gastrointestinal tract, where it has a beneficial effect in addition to its antibacterial properties. Current evidence shows that cyclical rifaximin usage in conjunction with a high-fiber diet is safe and effective for treating symptomatic uncomplicated diverticular disease, while the cost-effectiveness of long-term treatment is unknown. The use of rifaximin to prevent recurrent diverticulitis is promising, but further studies are needed to confirm its therapeutic benefit. Unfortunately, there is no available evidence on the efficacy of rifaximin treatment for acute uncomplicated diverticulitis.

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.

Nocebo response intensity and influencing factors in the randomized clinical trials of irritable bowel syndrome: A systematic review and meta-analysis

Objective

To estimate the magnitude of the nocebo response and explore its influencing factors in irritable bowel syndrome (IBS).

Methods

The PubMed, Embase, and Cochrane Library databases were searched up to March 2021. We performed a random effects meta-analysis of the proportion of adverse events (AEs) in placebo-treated patients with IBS who are involved in parallel-designed, randomized, placebo-controlled trials investigating pharmacological interventions and evaluated the effect of trial characteristics on the magnitude of the nocebo response rate.

Results

A total of 6,107 studies were identified from the databases. After evaluation, 53 met the eligibility criteria and were included. The overall pooled nocebo response rate was 32% (95% CI: 26-38%). The most commonly reported AEs were headache (9%), nasopharyngitis (7%), abdominal pain (4%), and nausea (4%). The nocebo response rate was low compared with that in the treatment group applying probiotics, antispasmodics, and Traditional Chinese medicine, but high compared with that in antibiotic treatment group. The nocebo rate in patients using diaries to record AEs was lower than the average, and was higher in patients recording through checkup.

Discussion

Patients with IBS have significant nocebo response intensity in clinical trials. Based on findings in this study, we recommend the researchers pay attention to the common AEs and carefully analyze the relation to the intervention.

Current and Future Therapeutic Options for Irritable Bowel Syndrome with Diarrhea and Functional Diarrhea

Irritable bowel syndrome with diarrhea and functional diarrhea are disorders of gut-brain interaction presenting with chronic diarrhea; they have significant impact on quality of life. The two conditions may exist as a continuum and their treatment may overlap. Response to first-line therapy with antispasmodics and anti-diarrheal agents is variable, leaving several patients with suboptimal symptom control and need for alternative therapeutic options. Our aim was to discuss current pharmacologic options and explore alternative therapeutic approaches and future perspectives for symptom management in irritable bowel syndrome with diarrhea and functional diarrhea. We conducted a search of PubMed, Cochrane, clinicaltrial.gov, major meeting abstracts for publications on current, alternative, and emerging drugs for irritable bowel syndrome with diarrhea and functional diarrhea. Currently approved therapeutic options for patients with first-line refractory irritable bowel syndrome with diarrhea and functional diarrhea include serotonin-3 receptor antagonists, eluxadoline and rifaximin. Despite their proven efficacy, cost and availability worldwide impact their utilization. One-third of patients with disorders of gut-brain interaction with diarrhea have bile acid diarrhea and may benefit from drugs targeting bile acid synthesis and excretion. Further understanding of underlying pathophysiology of irritable bowel syndrome with diarrhea and functional diarrhea related to bile acid metabolism, gastrointestinal transit, and microbiome has led to evaluation of novel therapeutic approaches, including fecal microbiota transplantation and enterobacterial "crapsules". These opportunities to treat disorders of gut-brain interaction with diarrhea should be followed with formal studies utilizing large samples of well-characterized patients at baseline and validated response outcomes as endpoints for regulatory approval.

AGA Clinical Practice Guideline on the Pharmacological Management of Irritable Bowel Syndrome With Diarrhea

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder associated with significant disease burden. This American Gastroenterological Association Guideline is intended to support practitioners in decisions about the use of medications for the pharmacological management of IBS with predominant diarrhea (IBS-D) and is an update of a prior technical review and guideline.

METHODS

The Grading of Recommendations Assessment, Development and Evaluation framework was used to assess evidence and make recommendations. The technical review panel prioritized clinical questions and outcomes according to their importance for clinicians and patients and conducted an evidence review of the following agents: eluxadoline, rifaximin, alosetron, loperamide, tricyclic antidepressants, selective serotonin reuptake inhibitors, and antispasmodics. The guideline panel reviewed the evidence and used the Evidence-to-Decision Framework to develop recommendations.

CONCLUSIONS

The panel agreed on 8 recommendations for the management of patients with IBS-D. The panel made conditional recommendations for eluxadoline, rifaximin, alosetron, (moderate certainty), loperamide (very low certainty), tricyclic antidepressants, and anstispasmodics (low certainty). The panel made a conditional recommendation against the use of selective serotonin reuptake inhibitors (low certainty).

A therapeutic guide on pediatric irritable bowel syndrome and functional abdominal pain-not otherwise specified

Disorders of the gut-brain interaction negatively impact quality of life and carry a substantial socioeconomic burden. Irritable bowel syndrome (IBS) and functional abdominal pain-not otherwise specified (FAP-NOS) are common functional abdominal pain disorders in childhood. The pathophysiology is not fully understood, and high-quality intervention trials and international guidelines are missing. Therefore, the management of these disorders remains challenging. This review aims to provide an up-to-date overview of therapeutic possibilities for pediatric IBS or FAP-NOS and recommends management strategies. To prevent unnecessary referrals and extensive costs, it is fundamental to make a positive diagnosis of IBS or FAP-NOS in children with chronic abdominal pain with only minimal investigations. A tailor-made approach for each patient, based on the accompanying physical and psychological symptoms, is proposed to date.

CONCLUSION

Shared decision-making including non-pharmacological and pharmacological interventions should be considered and discussed with the family.

WHAT IS KNOWN

• Irritable bowel syndrome and functional abdominal pain-not otherwise specified are common in childhood. • Although the number of treatment options has grown recently, managing these disorders can be challenging and unsatisfactory, and no evidence-based international management guidelines are available.

WHAT IS NEW

• We suggest using a stepwise individualized approach to management, where after first-line management, both non-pharmacological and pharmacological interventions should be discussed.

Functional bowel disorders with diarrhoea: Clinical guidelines of the United European Gastroenterology and European Society for Neurogastroenterology and Motility

Irritable bowel syndrome with diarrhoea (IBS‐D) and functional diarrhoea (FDr) are the two major functional bowel disorders characterized by diarrhoea. In spite of their high prevalence, IBS‐D and FDr are associated with major uncertainties, especially regarding their optimal diagnostic work‐up and management. A Delphi consensus was performed with experts from 10 European countries who conducted a literature summary and voting process on 31 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation criteria. Consensus (defined as >80% agreement) was reached for all the statements. The panel agreed with the potential overlapping of IBS‐D and FDr. In terms of diagnosis, the consensus supports a symptom‐based approach also with the exclusion of alarm symptoms, recommending the evaluation of full blood count, C‐reactive protein, serology for coeliac disease, and faecal calprotectin, and consideration of diagnosing bile acid diarrhoea. Colonoscopy with random biopsies in both the right and left colon is recommended in patients older than 50 years and in presence of alarm features. Regarding treatment, a strong consensus was achieved for the use of a diet low fermentable oligo‐, di‐, monosaccharides and polyols, gut‐directed psychological therapies, rifaximin, loperamide, and eluxadoline. A weak or conditional recommendation was achieved for antispasmodics, probiotics, tryciclic antidepressants, bile acid sequestrants, 5‐hydroxytryptamine‐3 antagonists (i.e. alosetron, ondansetron, or ramosetron). A multinational group of European experts summarized the current state of consensus on the definition, diagnosis, and management of IBS‐D and FDr.

Bile acid-gut microbiota crosstalk in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction with an increasing prevalence, and its precise aetiology remains unclear. Gut microbiota dysbiosis has been found to be associated with IBS pathogenesis. In addition, a high incidence of bile acid diarrhoea and disturbed bile acid metabolism has been observed in IBS patients. The abundant microorganisms inhabited in human gut have essential functions in bile acid biotransformation, and can immensely affect the size and constitution of bile acid pool. Meanwhile, the alterations of bile acid profile can inversely interfere with the gut microbiota. This review discussed the role of intricate correlations between bile acids and gut microbiota in IBS pathogenesis and delineated the possible molecular mechanisms, mainly the signalling induced by farnesoid X receptor and transmembrane G protein-coupled receptor 5. Besides, some biomarkers for identifying bile acid diarrhoea in IBS population were listed, assisting the diagnosis and classification of IBS. Moreover, it also assessed some therapeutic strategies for IBS that regulate the bile acid-gut microbiota axis, such as dietary modulation, probiotics/prebiotics, faecal microbiota transplantation, and antibiotics. Collectively, this article illustrated the relationship between bile acids and gut microbiota in IBS pathophysiology and might offer some novel therapeutic options for IBS.

An animal model of limitation of gut colonization by carbapenemase-producing Klebsiella pneumoniae using rifaximin

Current knowledge suggests that infection by carbapenem-resistant enterobacteria is preceded by gut colonization. It is hypothesized that colonization is eradicated by non-absorbable antibiotics like rifaximin. We investigated the effect of rifaximin against carbapenem-resistant Klebsiella pneumoniae (CRKP) in vitro and in a mouse model. We studied the in vitro efficacy of rifaximin against 257 CRKP clinical isolates, 188 KPC producers and 69 OXA-48 producers, by minimum inhibitory concentration and time-kill assays. We then developed a model of gut colonization by feeding 30 C57Bl6 mice with 10⁸ cfu of one KPC-KP isolate for 7 days; mice were pre-treated orally with saline, omeprazole or ampicillin. Then, another 60 mice with established KPC-2 gut colonization received orally for 7 consecutive days rifaximin 180 mg/kg dissolved in ethanol and 4% bile or vehicle. On days 0, 3 and 7 stool samples were collected; mice were sacrificed for determination of tissue outgrowth. At a concentration of 1000 μg/ml rifaximin inhibited 84.8% of CRKP isolates. Α 3 × log₁₀ decrease of the starting inoculum was achieved by 100, 250 and 500 μg/ml of rifaximin after 24 h against 25, 55 and 55% of isolates. Pre-treatment with ampicillin was necessary for gut colonization by KPC-KP. Treatment with rifaximin succeeded in reducing KPC-KP load in stool and in the intestine. Rifaximin inhibits at clinically meaningful gut concentrations the majority of CRKP isolates and is efficient against gut colonization by KPC-KP.

Review Article: Current and future treatment approaches for IBS with diarrhoea (IBS-D) and IBS mixed pattern (IBS-M)

BACKGROUND

Irritable bowel syndrome-diarrhoea (IBS-D) and IBS-mixed stool pattern (IBS-M) are disorders of gut-brain interaction characterised by abdominal pain associated with diarrhoea or both diarrhoea and constipation respectively. The pathophysiology of IBS-D/M is multifactorial and not completely understood; thus, treatment is aimed at multiple mechanisms such as altering gut microbiota, visceral hypersensitivity, intestinal permeability, gut-brain interaction and psychological strategies.

AIM

The goal of this article was to provide an up-to-date review of the current evidence for both non-pharmacological and pharmacological treatment options in IBS-D and IBS-M. Future treatments for IBS-D and IBS-M will also be discussed.

METHODS

Medline and Embase database searches (through April 30 2021) to identify clinical studies in subjects with IBS-D in which dietary modification, alternative treatments (probiotics, acupuncture, exercise) as well as FDA-approved medications were used.

RESULTS

Dietary modification is often the first line of therapy. Furthermore, lifestyle treatments include complementary alternative medications (CAM), probiotics and peppermint oil are useful adjuncts but have not specifically been described in IBS-D/M. Evidence strongly supports psychotherapy in the treatment of IBS. Beyond over-the counter anti-diarrhoeals, anti-spasmodics and anti-depressants, pharmacological treatment now includes treating for bile acid malabsorption and the FDA-approved medications rifaximin, eluxadoline and alosetron.

CONCLUSIONS

The treatment of IBS-D/M ideally involves a multidisciplinary approach of primary care, gastroenterologist and psychologist. Treatment often involves both non-pharmacological and pharmacological therapies. Future therapies may include faecal microbial transplant, Crofelemer and serotonin antagonists, but further studies are needed.

Functional gastrointestinal disorders. Overlap syndrome Clinical guidelines of the Russian Scientific Medical Society of Internal Medicine and Gastroenterological Scientific Society of Russia

.

Diarrhea-Predominant and Constipation-Predominant Irritable Bowel Syndrome: Current Prescription Drug Treatment Options

Irritable bowel syndrome (IBS) is a heterogenous disease with a variety of therapeutic options, including eight prescription drugs approved for use in IBS in the USA. Choosing among the myriad treatment options requires attention to patient preferences both on clinical outcomes and costs associated with treatment. We performed a narrative review of the literature to summarize these important determinants of treatment choice including: labeled indications; clinical profiles of efficacy, safety, and tolerability of prescription drugs; and cost-effectiveness for diarrhea-predominant IBS drugs (IBS-D: alosetron, eluxadoline, and rifaximin) and constipation-predominant IBS drugs (IBS-C: linaclotide, lubiprostone, plecanatide, tegaserod, and tenapanor). We then review the standard model of shared decision-making aimed at guiding an informed, patient-centered discussion to integrate comparative clinical and cost outcomes toward choosing an IBS treatment in practice.

Rifaximin microbial resistance and its efficacy and safety as a secondary prophylaxis of hepatic encephalopathy in patients with hepatitis C virus-related cirrhosis

BACKGROUND AND AIM

Rifaximin is an oral antibiotic with promising efficacy in the reduction of hepatic encephalopathy (HE) recurrence. Development of microbial resistance to rifaximin is not studied yet in HE. The study aim was to assess the microbial resistance, safety and efficacy of rifaximin as secondary prophylaxis of HE.

METHOD

In this open-label parallel, prospective interventional study, 100 patients were randomly allocated either to receive 400 mg rifaximin 3 times/d plus 30-45 mL lactulose 3 times/d (intervention group) or to receive the standard of care only which is lactulose alone (control group) for 6 months. The primary outcome of the study was the difference between minimum inhibitory concentration (MIC) of rifaximin among the two studied groups at the end of treatment. The secondary outcomes included the time to first episode of HE, time to first hospitalisation, and patient's survival.

RESULTS

The MIC did not differ significantly after treatment exposure compared with baseline either between groups or within the same group. The time to new episode of HE was 18.84 ± 6.49 weeks (mean ± SD) in the intervention group and was significantly longer (P = .002) than that in the control group 14 ± 7.52 weeks. Moreover, only 23 (46%) patients developed overt HE in the intervention group compared with 35 patients (70%) in the control group (P = .005). Also, there was an observed 32% reduction in the risk of hospitalisation in intervention group compared with control group.

CONCLUSION

Rifaximin succeeded to maintain remission from new episodes of HE in hepatitis C virus cirrhotic patients with limited potential for development of microbial resistance over the study period. ClinicalTrials.gov Identifier: NCT04736836.

[The new guideline on irritable bowel syndrome: what is new?]

IRRITABLE BOWEL SYNDROME

WHAT IS NEW?:  The following refers only to irritable bowel syndrome (IBS) in adults. The new guideline includes a separate section on IBS for paediatric patients. Irritable bowel syndrome (IBS) presents as a heterogeneous picture with chronic abdominal complaints related to the bowel. These are usually accompanied by changes in bowel movements and lead to impaired quality of life. The genesis is multifactorial and there are complex underlying pathophysiological mechanisms associated with IBS. Thus, disturbances in various components of the gut-brain axis and the increasing importance of the microbiome can be identified. Various psychological comorbidities also play a role.

DIAGNOSTICS

The diagnosis is made by a thorough anamnesis and symptom-oriented exclusion of important differential diagnoses. A subdivision into different subtypes depending on the main symptoms is beneficial for the further management of IBS patients. The diagnosis of IBS should be made as early as possible after reliable exclusion of the important differential diagnoses. If diarrhoea dominates as a symptom, a detailed differential diagnosis and functional diagnosis should be carried out.

THERAPY

There is no proven causal and no established standard therapy. Due to the variable genesis and symptom manifestation of IBS, a broad spectrum of therapy options results, whereby there is no individual prediction regarding effectiveness and therefore every therapy is initially probationary. Symptom-independent general therapies that can be used for all subtypes include dietary methods (e. g. the low-FODMAP diet), probiotics, psychotherapy methods and complementary medicine. The choice of symptom-dependent drug treatments is made according to the subtype/main symptom. In the case of diarrhoea, bile acid binders, the non-absorbable antibiotic rifaximin or, in individual cases, 5-HT₃-antagonists can be used in addition to loperamide. In constipation, prucalopride and linaclotide have value in addition to the use of soluble fibre and macrogol/other laxatives. For abdominal pain/cramps, studies show good results for spasmolytics, especially peppermint oil, and for tricyclic-type antidepressants. For the main symptom of flatulence, probiotics, rifaximin and especially the low-FODMAP diet can show positive results in studies.

Emerging Role of the Gut Microbiome in Irritable Bowel Syndrome

Advances in bioinformatics have facilitated investigation of the role of gut microbiota in patients with irritable bowel syndrome (IBS). This article describes the evidence from epidemiologic and clinical observational studies highlighting the link between IBS and gut microbiome by investigating postinfection IBS, small intestinal bacterial overgrowth, and microbial dysbiosis. It highlights the effects of gut microbiota on mechanisms implicated in the pathophysiology of IBS, including gut-brain axis, visceral hypersensitivity, motility, epithelial barrier, and immune activation. In addition, it summarizes the current evidence on microbiome-guided therapies in IBS, including probiotics, antibiotics, diet, and fecal microbiota transplant.

Targeted pharmacotherapy of irritable bowel syndrome

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal (GI) disorder with negative impact on quality of life and it represents a substantial economic burden on healthcare cost. The medical management of IBS is symptom directed. This review provides an update related to clinical trial data for novel treatment modalities in IBS targeting the gut epithelium secretagogue receptors and channels.

RECENT FINDINGS

The new Rome IV criteria define functional gastrointestinal disorders (FGID) as disorders of the gut-brain interaction. Pharmacological treatment modalities for IBS target gastrointestinal receptors and ion channels, peripheral opioid receptor, gut serotonin receptors, and the gut microbiome. New targeted pharmacotherapies have shown efficacy and safety in the treatment of patients with IBS.

SUMMARY

Diagnostic criteria for FGID, including IBS, have been revised in Rome IV and are defined as gut-brain disorders. Newly approved pharmacotherapy options with proven efficacy and acceptable side-effect profiles are available for the symptom-based management of IBS.

Management of irritable bowel syndrome with diarrhea: focus on eluxadoline

OBJECTIVE

We sought to summarize current recommendations for the diagnosis of diarrhea-predominant irritable bowel syndrome (IBS-D) and describe available management options, highlighting a newer US Food and Drug Administration (FDA)-approved agent, eluxadoline.

METHODS

Literature on IBS-D was assessed up to January 2020 using PubMed, with key search terms including "IBS-D diagnosis", "IBS-D management", and "eluxadoline".

RESULTS

IBS is a common gastrointestinal disorder affecting up to 14% of US adults and is particularly prevalent in women and those aged under 50. Symptoms include abdominal pain associated with altered bowel habits (i.e. diarrhea and/or constipation subtyped based on the predominant stool pattern). As IBS-D is challenging to manage with varying symptom severity, effective treatment requires a personalized management approach. Evidence-based therapeutic options endorsed by the American Gastroenterological Association and the American College of Gastroenterology can be used to effectively guide treatment. Dietary and lifestyle modifications, including adequate hydration, reducing caffeine and alcohol intake, and increasing soluble fiber intake may lead to symptom improvement. Over-the-counter medications such as loperamide are frequently recommended and may improve stool frequency and rectal urgency; however, for the outcome of abdominal pain, mixed results have been observed. Several off-label prescription medications are useful in IBS-D management, including tricyclic antidepressants, bile acid sequestrants, and antispasmodics. Three prescription medications have been approved by the FDA for IBS-D: alosetron, eluxadoline, and rifaximin.

CONCLUSIONS

IBS-D can be effectively managed in the primary care setting in the absence of alarm features. Benefits and risks of pharmacologic interventions should be weighed during treatment selection.

ACG Clinical Guideline: Management of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a highly prevalent, chronic disorder that significantly reduces patients' quality of life. Advances in diagnostic testing and in therapeutic options for patients with IBS led to the development of this first-ever American College of Gastroenterology clinical guideline for the management of IBS using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Twenty-five clinically important questions were assessed after a comprehensive literature search; 9 questions focused on diagnostic testing; 16 questions focused on therapeutic options. Consensus was obtained using a modified Delphi approach, and based on GRADE methodology, we endorse the following: We suggest that a positive diagnostic strategy as compared to a diagnostic strategy of exclusion be used to improve time to initiating appropriate therapy. We suggest that serologic testing be performed to rule out celiac disease in patients with IBS and diarrhea symptoms. We suggest that fecal calprotectin be checked in patients with suspected IBS and diarrhea symptoms to rule out inflammatory bowel disease. We recommend a limited trial of a low fermentable oligosaccharides, disacchardies, monosaccharides, polyols (FODMAP) diet in patients with IBS to improve global symptoms. We recommend the use of chloride channel activators and guanylate cyclase activators to treat global IBS with constipation symptoms. We recommend the use of rifaximin to treat global IBS with diarrhea symptoms. We suggest that gut-directed psychotherapy be used to treat global IBS symptoms. Additional statements and information regarding diagnostic strategies, specific drugs, doses, and duration of therapy can be found in the guideline.

Diarrhea-Predominant Irritable Bowel Syndrome: Medical Management Update

Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder, which impacts the quality of life, work productivity and social activities of patients. Diarrhea-predominant IBS (IBS-D) is one of several subtypes, and accounts for approximately one third of all cases. Currently available treatments are typically unable to alleviate the cardinal symptoms of IBS-D, including abdominal pain and diarrhea, and a clinical unmet need remains for an effective treatment which simultaneously relieves multiple symptoms. Patients may benefit from a multipronged, individualized approach, including dietary modifications, and psychological and pharmacological therapies. The aim of this review is to provide an update on the available and upcoming treatment options for IBS-D in Canada, with reference to the recently updated Canadian IBS consensus guidelines. Initial treatment approaches include lifestyle modifications, dietary modifications, and non-prescription therapies such as peppermint oil. While some medications such as tricyclic antidepressants are also used to treat IBS-D symptoms, eluxadoline and rifaximin are the only two pharmacological therapies approved for the treatment of IBS-D in Canada. Key clinical trial data for the currently available pharmacological options are presented to provide an overview of the efficacy and safety of these agents.

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.

Abdominal Pain Response to Rifaximin in Patients With Irritable Bowel Syndrome With Diarrhea

INTRODUCTION

Abdominal pain is the principal symptom of irritable bowel syndrome (IBS). This analysis examined abdominal pain response in adults with IBS with diarrhea (IBS-D) receiving the nonsystemic antibiotic rifaximin.

METHODS

In the Targeted Nonsystemic Antibiotic Rifaximin Gut-Selective Evaluation of Treatment for IBS-D 3 trial, adults with IBS-D received open-label rifaximin 550 mg 3 times daily for 2 weeks, followed by the 4-week post-treatment phase assessing abdominal pain and stool consistency response. Responders were followed for up to 18 additional weeks; patients with recurrence were randomly assigned to receive two 2-week courses of double-blind rifaximin 550 mg 3 times daily or placebo, separated by 10 weeks. Analyses evaluated mean weekly improvements from baseline (e.g., ≥30%, ≥40%, and ≥50%) in abdominal pain during the 4-week post-repeat-treatment phases.

RESULTS

Of the 2,438 evaluable patients, 1,384 (56.8%) had abdominal pain response to open-label rifaximin (≥30% improvement from baseline in the mean weekly abdominal pain score during ≥2 of the first 4 weeks post-treatment). Weekly decrease (improvement) in responders' mean abdominal pain score (scale range, 0-10) from baseline ranged from -2.6 to -3.3 points during the 18-week follow-up. After the first double-blind repeat treatment, a significantly higher percentage of rifaximin-treated patients were abdominal pain responders (53.9% [172/319]) vs placebo (44.4% [134/302], P = 0.02), with similar results after the second repeat treatment (52.9% [155/293] vs 44.7% [123/275], respectively, P = 0.047). A significantly higher percentage of rifaximin-treated patients were weekly abdominal pain responders for ≥50% of the 18-week double-blind repeat treatment phase (47.9% [138/288] vs 35.9% [97/270], P = 0.004).

DISCUSSION

Rifaximin is efficacious in improving abdominal pain in adults with IBS-D.

Current US Food and Drug Administration-Approved Pharmacologic Therapies for the Treatment of Irritable Bowel Syndrome with Diarrhea

Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by abdominal pain and alterations in stool form and/or frequency, leading to reduced quality of life. Pharmacologic agents currently approved by the US Food and Drug Administration for treatment of IBS with diarrhea (IBS-D) in adults are the nonsystemic antibiotic rifaximin, the mixed µ- and κ-opioid receptor agonist/δ-opioid antagonist eluxadoline, and the selective serotonin 5-HT₃ antagonist alosetron (the last of which is indicated only in women with severe IBS-D refractory to conventional therapy). Both eluxadoline and alosetron are administered as chronic daily therapies; rifaximin is given as a 2-week course of treatment with repeat courses administered as needed for symptom recurrence. Presumed mechanisms of action of rifaximin include modulation of the gut microbiota, anti-inflammatory activity, normalization of visceral hypersensitivity, and reduction in intestinal permeability. Eluxadoline targets opioid receptors in the gastrointestinal (GI) tract, resulting in decreased GI motility, fluid secretion, and visceral pain perception. Alosetron antagonizes serotonergic afferent neural signals and also slows GI motility. The efficacy and safety of these agents have been investigated in several rigorous clinical trials, and it has been demonstrated that they improve global and individual IBS symptoms. This review highlights the pivotal efficacy and safety data of the three pharmacologic agents currently indicated in the USA for the management of IBS-D in adults.Funding: Salix Pharmaceuticals.

Management of irritable bowel syndrome with diarrhea: a review of nonpharmacological and pharmacological interventions

Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) condition involving numerous potential causative factors (e.g. alterations in gut microbiota, motility, brain-gut axis). Several interventions are available for the management of patients with IBS, but no universal management algorithm currently exists. The aim of this article is to review interventions that may be considered in the management of patients with IBS with diarrhea (IBS-D). Nonpharmacological interventions include dietary and lifestyle modification, which are generally used as first-line therapy. Probiotics have demonstrated efficacy and safety in patients with IBS, but studies are inconsistent in strains examined, dosing, and treatment duration. Psychological therapies (e.g. cognitive behavioral therapy, hypnotherapy) also may improve IBS symptoms. Pharmacological interventions for the management of IBS-D include the US Food and Drug Administration-approved agents eluxadoline, rifaximin, and alosetron, as well as loperamide, smooth muscle antispasmodics, bile acid sequestrants, and antidepressants (i.e. tricyclic antidepressants, selective serotonin reuptake inhibitors). Eluxadoline and rifaximin have been shown to improve abdominal pain and stool consistency in patients with IBS-D. In addition, data indicate that alosetron improves IBS symptoms; however, it is approved only for women with severe IBS-D. Of the three approved agents, rifaximin has the most favorable safety profile. The risk-benefit ratio is an important consideration with every medication, but is especially important in the treatment of functional GI disorders such as IBS-D. Thus, the most troublesome symptoms, quality of life, symptom intensity, and individual patient preferences should be considered when formulating a management plan for patients with IBS-D.

Bacillus spp. Spores-A Promising Treatment Option for Patients with Irritable Bowel Syndrome

Dysbiosis is a condition that can cause various clinical disorders, from gastrointestinal problems to allergies or even cancer. Resetting the microbiota using antibiotics and/or probiotics could be a possible therapy for many diseases. The aim of this study was to evaluate the effects of three treatment regimens in patients with irritable bowel syndrome (IBS). The regimens were short-term rifaximin treatment (10 days) followed by either a nutraceutical agent (G1) or a low- Fermentable, Oligo-, Di-, Monosaccharide and Polyol (FODMAP) diet (24 days) (G3) or treatment with MegaSporeBiotic a mixture of spores of five Bacillus spp. for medium-term (34 days) (G2). Ninety patients with IBS without constipation were enrolled and divided into three groups (G1, G2, G3). Patients in G1 and G3 were evaluated over four visits (baseline/first day (V1), 10 days (V2), 34 days (V3), 60 days (V4)), and, those in G2 over three visits (V1, V3, V4). Severity score, quality of life, and parameters from the rectal volume sensation test were determined. The results demonstrated that patients treated with MegaSporeBiotic, compared with those treated with rifaximin followed by nutraceutical or low-FODMAP diet, had similar severity scores and rectal volume sensation test results for all parameters tested and statistically significant improvement in measurements of quality of life.

Second Asian Consensus on Irritable Bowel Syndrome

BACKGROUND/AIMS

There has been major progress in our understanding of the irritable bowel syndrome (IBS), and novel treatment classes have emerged. The Rome IV guidelines were published in 2016 and together with the growing body of Asian data on IBS, we felt it is timely to update the Asian IBS Consensus.

METHODS

Key opinion leaders from Asian countries were organized into 4 teams to review 4 themes: symptoms and epidemiology, pathophysiology, diagnosis and investigations, and lifestyle modifications and treatments. The consensus development process was carried out by using a modified Delphi method.

RESULTS

Thirty-seven statements were developed. Asian data substantiate the current global viewpoint that IBS is a disorder of gut-brain interaction. Socio-cultural and environmental factors in Asia appear to influence the greater overlap between IBS and upper gastrointestinal symptoms. New classes of treatments comprising low fermentable oligo-, di-, monosacharides, and polyols diet, probiotics, non-absorbable antibiotics, and secretagogues have good evidence base for their efficacy.

CONCLUSIONS

Our consensus is that all patients with functional gastrointestinal disorders should be evaluated comprehensively with a view to holistic management. Physicians should be encouraged to take a positive attitude to the treatment outcomes for IBS patients.

Systematic review with meta-analysis: the efficacy of prebiotics, probiotics, synbiotics and antibiotics in irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a chronic functional bowel disorder. Disturbances in the gastrointestinal microbiome may be involved in its aetiology.

AIM

To perform a systematic review and meta-analysis to examine the efficacy of prebiotics, probiotics, synbiotics and antibiotics in IBS.

METHODS

MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to July 2017). Randomised controlled trials (RCTs) recruiting adults with IBS, comparing prebiotics, probiotics, synbiotics or antibiotics with placebo or no therapy were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% confidence interval (CI). Continuous data were pooled using a standardised mean difference with a 95% CI.

RESULTS

The search identified 4017 citations. Data for prebiotics and synbiotics were sparse. Fifty-three RCTs of probiotics, involving 5545 patients, were eligible. Particular combinations of probiotics, or specific species and strains, appeared to have beneficial effects on global IBS symptoms and abdominal pain, but it was not possible to draw definitive conclusions about their efficacy. There were five trials of similar design that used rifaximin in non-constipated IBS patients, which was more effective than placebo (RR of symptoms persisting = 0.84; 95% CI 0.79-0.90). Adverse events were no more common with probiotics or antibiotics.

CONCLUSIONS

Which particular combination, species or strains of probiotics are effective for IBS remains, for the most part, unclear. Rifaximin has modest efficacy in improving symptoms in non-constipated IBS.

Review article: an analysis of safety profiles of treatments for diarrhoea-predominant irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is multifactorial in nature, and a wide range of therapies is available to manage symptoms of this common disorder.

AIM

To provide an overview of the safety of interventions that may be used to manage patients with diarrhoea-predominant IBS (IBS-D).

METHODS

Medline and Embase database searches (through 02 May 2018) to identify clinical studies that evaluated treatment safety and/or efficacy in adults with IBS-D.

RESULTS

IBS-D treatments include dietary modification, probiotics, serotonin receptor antagonists, opioid receptor agonists and antagonists, nonsystemic antibiotics, bile acid sequestrants, antidepressants, and complementary and alternative therapies. These treatments vary in administration frequency (eg, daily; short-course therapy) and target various pathophysiologic factors. Safety profiles vary considerably by treatment among IBS-D therapies. The number needed to harm (defined as the number of patients treated to encounter an adverse event) was lowest (worse) for antidepressants (8.5) and highest (best) for probiotics (35), and the number needed to harm (defined as the number of patients who discontinued due to an adverse event) was lowest for tricyclic antidepressants (9) and highest for rifaximin (8971). Notable safety concerns with IBS-D treatments include pancreatitis with eluxadoline, ischaemic colitis and serious complications of constipation with alosetron, and cardiac adverse events with loperamide and tricyclic antidepressants. Treatment decisions need to account for medication risks and adverse events for each patient.

CONCLUSIONS

Multiple treatment options are now available for patients with IBS-D. However, the safety profiles of these agents vary widely by number needed to harm value. Providers should consider both safety and efficacy of a specific intervention when determining how best to manage patients' IBS-D symptoms.

Short-course therapy for diarrhea-predominant irritable bowel syndrome: understanding the mechanism, impact on gut microbiota, and safety and tolerability of rifaximin

Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) disorder characterized by abdominal pain that occurs with defecation or alterations in bowel habits. Further classification is based on the predominant bowel habit: constipation-predominant IBS, diarrhea-predominant IBS (IBS-D), or mixed IBS. The pathogenesis of IBS is unclear and is considered multifactorial in nature. GI dysbiosis, thought to play a role in IBS pathophysiology, has been observed in patients with IBS. Alterations in the gut microbiota are observed in patients with small intestinal bacterial overgrowth, and overgrowth may occur in a subset of patients with IBS. The management of IBS includes therapies targeting the putative factors involved in the pathogenesis of the condition. However, many of these interventions (eg, eluxadoline and alosetron) require long-term, daily administration and have important safety considerations. Agents thought to modulate the gut microbiota (eg, antibiotics and probiotics) have shown potential benefits in clinical studies. However, conventional antibiotics (eg, neomycin) are associated with several adverse events and/or the risk of bacterial antibiotic resistance, and probiotics lack uniformity in composition and consistency of response in patients. Rifaximin, a nonsystemic antibiotic administered as a 2-week course of therapy, has been shown to be safe and efficacious for the treatment of IBS-D. Rifaximin exhibits a favorable benefit-to-harm ratio when compared with daily therapies for IBS-D (eg, alosetron and tricyclic antidepressants), and rifaximin was not associated with the emergence of bacterial antibiotic resistance. Thus, short-course therapy with rifaximin is an appropriate treatment option for IBS-D.

Guidelines on the management of irritable bowel syndrome: In memory of Professor Witold Bartnik

These guidelines constitute an update of the previous "Recommendations on the management of irritable bowel syndrome" issued in 2008. They have been developed by a Task Force organized by the Governing Board of the Polish Society of Gastroenterology. They discuss, with particular emphasis on new scientific data covering papers published since 2008, the aetiology, epidemiology, clinical presentation, diagnostic principles and criteria for the diagnosis, and recommendations for the treatment of irritable bowel syndrome (IBS). The English-language acronym for the syndrome (IBS) has become popular in medical and popular scientific language. It is also widely recognized by patients who identify with this diagnosis. Therefore, in the discussed guidelines, this is what we will use.

Reduction of the frequency of recurrent diverticulitis episodes under treatment with the integrative medicine therapies Carpellum Mali comp. and Kalium aceticum comp.-A case report

BACKGROUND

Colonic diverticula develop in at least 60% of elderly patients. Less than 25% of these develop diverticulitis. Recurrent episodes are experienced by about 13% of the symptomatic patients. The effect on prevention of recurrent diverticulitis of currently used therapies is controversial. Surgical colon resection is used in some patients in emergency or to prevent future episodes and complications. Carpellum Mali comp. (Juglans regia, Testa; Pirus malus, Carpellum) and Kalium aceticum comp. (Kalium carbonicum, Acetum vini destillatum, Antimonit, Crocus sativus, Spiritus e vino, Corallium rubrum) - preparations of Integrative Anthroposophic Medicine - have been used for at least 60 years to improve chronic abdominal pain and to treat obstipation, irritable bowel syndrome and colitis.

CASE PRESENTATION

A 72-year-old retired physician presented in 2013 with a 7-year history of recurrent diverticulitis. During the first 6 years, three to four episodes each year required antibiotic therapy. In 2013 the episodes became more frequent, occurring approximately every 2 months. The patient was concerned about risks from repeated antibiotic treatment and the potential need for surgery. Oral Carpellum Mali comp. and subcutaneous Kalium aceticum comp. treatments were added to the therapy in March. The patient experienced improvement over 4 months without any symptoms. In the following 28 months she had 4 minor diverticulitis episodes, followed by 11-months without any flares; she reported no side effects in the 41-month follow-up period.

CONCLUSION

Carpellum Mali comp. and Kalium aceticum comp. seem to have been helpful in the case presented here. Experiences with theses remedies in recurrent diverticulitis should be collected to determine whether it would be meaningful to carry out further investigations.

New concepts on intestinal microbiota and the role of the non-absorbable antibiotics with special reference to rifaximin in digestive diseases

Digestive diseases are a broad range of chronic disorders that substantially and negatively impact the patients' quality of life. Here, we review our current understanding on the pathophysiology of hepatic encephalopathy, irritable bowel syndrome, and diverticular disease, with a special focus on the gut microbiota composition associated with these disorders. Furthermore, we review the current clinical practice for their therapeutic treatments, including probiotics, diet change, non-adsorbable disaccharides, and antibiotics. We highlight that broad-spectrum non-adsorbable antibiotics, such as rifaximin, are quite effective and safe for the treatment of all essayed digestive diseases.

Comparative effectiveness of pharmacological treatments for patients with diarrhea-predominant irritable bowel syndrome: Protocol of a systematic review and network meta-analysis

BACKGROUND

Several pharmacological treatments are recommended by guidelines with moderate to high evidence for the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D), but the comparative effectiveness and safety among these treatments are unknown. The review is to assess the comparative effectiveness and safety of pharmacological treatments for IBS-D using network meta-analysis.

METHODS

We will search Ovid Medline, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) for relevant randomized controlled trials (RCTs) that compare guideline-recommended pharmacological treatments with placebo or one of the treatments. We will include RCTs that recruit patients with IBS-D, RCTs that assess the improvement in IBS-D global symptoms, abdominal pain, stool frequency, or stool consistency, and RCTs that assess the responder rate and adverse event rate. We will use standardized mean difference to synthesize continuous variables and use odds ratio to synthesize categorical variables. Traditional meta-analysis will be performed to assess the comparative effectiveness of the pharmacological treatments in direct evidence, and network meta-analysis will be performed to combine both direct and indirect evidence. Transitivity of the evidence in the network will be assessed by using a generalized Cochrane Q statistic and net-heat plot.

CONCLUSIONS

The result of the review will inform clinical decisions for clinicians, patients, and police makers in the treatment of IBS-D.

RESULTS

Ethical approval and informed consent are not required for this systematic review. We will disseminate the result through a peer-reviewed journal and conference abstracts.

PROSPERO REGISTRATION NUMBER

PROSPERO CDR42018099294.

Rifaximin is associated with modest, transient decreases in multiple taxa in the gut microbiota of patients with diarrhoea-predominant irritable bowel syndrome

Rifaximin, a non-systemic antibiotic, is efficacious for the treatment of diarrhoea-predominant irritable bowel syndrome (IBS-D). Given the emerging association between the gut microbiota and IBS, this study examined potential effects of rifaximin on the gastrointestinal microbial community in patients with IBS-D. TARGET 3 was a randomised, double-blind, placebo-controlled, phase 3 study. Patients with IBS-D initially received open-label rifaximin 550 mg 3 times daily (TID) for 2 weeks. Patients who responded to the initial treatment and then relapsed were randomised to receive 2 repeat courses of rifaximin 550 mg TID or placebo for 2 weeks, with each course separated by 10 weeks. Stool samples were collected at the beginning and end of open-label treatment, at the beginning and end of the first double-blind treatment, and at the end of the study. As a secondary analysis to the TARGET 3 trial, the composition and diversity of the gut microbiota were assessed, from a random subset of patients, using variable 4 hypervariable region 16S ribosomal RNA gene sequencing. Samples from 103 patients were included. After open-label rifaximin treatment for 2 weeks, 7 taxa (e.g. Peptostreptococcaceae, Verrucomicrobiaceae, Enterobacteriaceae) had significantly lower relative abundance at a 10% false discovery rate threshold. The effects of rifaximin were generally short-term, as there was little evidence of significantly different changes in taxa relative abundance at the end of the study (up to 46 weeks) versus baseline. The results suggest that rifaximin has a modest, largely transient effect across a broad range of stool microbes. Future research may determine whether the taxa affected by rifaximin are causally linked to IBS-D. ClinicalTrials.gov identifier number: NCT01543178.

The gut microbiome and irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders encountered in clinical practice. It is a heterogeneous disorder with a multifactorial pathogenesis. Recent studies have demonstrated that an imbalance in gut bacterial communities, or "dysbiosis", may be a contributor to the pathophysiology of IBS. There is evidence to suggest that gut dysbiosis may lead to activation of the gut immune system with downstream effects on a variety of other factors of potential relevance to the pathophysiology of IBS. This review will highlight the data addressing the emerging role of the gut microbiome in the pathogenesis of IBS and review the evidence for current and future microbiome based treatments.

Pharmacokinetic drug evaluation of rifaximin for treatment of diarrhea-predominant irritable bowel syndrome

INTRODUCTION

Rifaximin is a poorly absorbable antibiotic with a broad-spectrum activity against both Gram-negative and -positive bacteria. It is active in the small intestine due to its high bile solubility, whereas in the aqueous environment of the colon, it shows limited efficacy against highly susceptible bacteria. These unique pharmacokinetic properties limit its systemic effects and can correct gut microflora imbalances. Thus, rifaximin has become a major therapeutic agent in several gastrointestinal diseases in which an imbalance in gut microflora may play a role, including diarrhea predominant irritable bowel syndrome (IBS-D). Area covered: This is an up-to-date review focusing on the efficacy of rifaximin in the treatment of IBS-D in both adult and pediatric populations. We will review the pharmacokinetic properties of rifaximin, including its absorption in health and disease, mechanisms of action, and interactions with other drugs. Expert opinion: Given its safety profile and its negligible absorption, rifaximin is a suitable treatment for IBS-D, in both adults and children. The possibility of modulating gut microbiota composition without side effects has made this drug an appealing therapeutic agent in highly prevalent gastrointestinal diseases. However, to date, monitoring for the development of resistant bacterial strains during long-term rifaximin use is still lacking.

Gut Microbiota-Based Therapies for Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common, heterogeneous disorder characterized by abdominal pain associated with changes in bowel habits. The pathogenesis of IBS is multifactorial and may relate to alterations in the gut microbiota, changes in visceral sensation and motility, and genetic and environmental factors. Administration of systemic antibiotics may increase the risk of IBS by altering gastrointestinal homeostasis. Therapeutic interventions for IBS with diarrhea that are thought to target alterations in the gut microbiota include the nonsystemic antibiotic rifaximin, the medical food serum-derived bovine immunoglobulin, prebiotics, probiotics, and dietary modification. SYN-010 is a modified-release statin formulation that reduces methane production by Methanobrevibacter smithii and is currently in development for the treatment of patients with constipation-predominant IBS. Use of these interventions in the management of patients with IBS may function to restore a healthy gut microbiota and ameliorate symptoms of IBS.

Modulation of the gut microbiota: a focus on treatments for irritable bowel syndrome

Irritable bowel syndrome (IBS), which is characterized by recurrent abdominal pain and disordered bowel habits, is one of the most common functional bowel disorders. IBS is a substantial burden on both patient health-related quality of life and healthcare costs. Several pathophysiologic mechanisms have been postulated for the occurrence of IBS, including altered gastrointestinal motility, visceral hypersensitivity, changes in gut permeability, immune activation, gut-brain dysregulation, central nervous system dysfunction, and changes in the gut microbiota. Of note, both qualitative and quantitative differences have been observed in the gut microbiota of a population with IBS versus a healthy population. Because of the substantial interest in the gut microbiota and its role as a therapeutic target in IBS, this article provides an overview of specific interventions with the potential to modulate the gut microbiota in IBS, including elimination diets, prebiotics, probiotics, synbiotics, and nonsystemic antibiotics. Although probiotics and synbiotics are generally well tolerated, differences in the composition and concentration of different bacterial species and inclusion or exclusion of prebiotic components varies widely across studies and has prevented strong recommendations on their use in IBS. For nonsystemic antibiotics, rifaximin is indicated in the United States for the treatment of IBS with diarrhea in adults and has been shown to be efficacious and well tolerated in well-designed clinical trials. Overall, more consistent evidence is needed regarding the efficacy and safety of elimination diets, prebiotics, probiotics, and synbiotics for the treatment of patients with IBS. Furthermore, additional well-designed studies are needed that examine alterations in the gut microbiota that occur with these interventions and their potential associations with clinical symptoms of IBS.

Diarrhea-predominant irritable bowel syndrome: Diagnosis, etiology, and new treatment considerations

PURPOSE

To provide an overview of irritable bowel syndrome (IBS), specifically the efficacy and tolerability of treatment options for diarrhea-predominant IBS (IBS-D).

DATA SOURCES

Research articles available via PubMed were reviewed.

CONCLUSIONS

IBS is a chronic multifactorial disorder that has a negative impact on patient-related quality of life. Genetic factors, psychosociologic factors, alterations in the gut microbiota, and changes in immune, motor, and sensory responses to various stimuli all may be involved in the development of IBS. While pharmacologic therapies for IBS-D have historically been limited (e.g., alosetron), newer therapies (eluxadoline and rifaximin), both approved in the United States in 2015, may be considered for appropriate patients for the management of IBS-D.

IMPLICATIONS FOR PRACTICE

Nurse practitioners play an important role in the diagnosis, care, and management of patients with IBS-D. The goals of therapy should be to reach a correct diagnosis before initiating therapy, provide reassurance to the patient, educate the patient on potential treatment options, improve IBS-D symptoms, minimize risk of harm with treatment, and maximize patient-related quality of life. The authors present a treatment algorithm to guide nurse practitioners on the management of patients with IBS-D.

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.

Identification and Treatment of New Inflammatory Triggers for Complex Regional Pain Syndrome: Small Intestinal Bacterial Overgrowth and Obstructive Sleep Apnea

Complex regional pain syndrome (CRPS) is evoked by conditions that may be associated with local and/or systemic inflammation. We present a case of long-standing CRPS in a patient with Ehlers-Danlos syndrome in which prolonged remission was attained by directing therapy toward concomitant small intestinal bacterial overgrowth, obstructive sleep apnea, and potential increased microglia activity. We theorize that cytokine production produced by small intestinal bacterial overgrowth and obstructive sleep apnea may act as stimuli for ongoing CRPS symptoms. CRPS may also benefit from the properties of low-dose naltrexone that blocks microglia Toll-like receptors and induces production of endorphins that regulate and reduce inflammation.