Longterm treatment of irritable bowel syndrome with cimetropium bromide: a double blind placebo controlled clinical trial

The Role of Bovine Kappa-Casein Glycomacropeptide in Modulating the Microbiome and Inflammatory Responses of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder marked by chronic abdominal pain, bloating, and irregular bowel habits. Effective treatments are still actively sought. Kappa-casein glycomacropeptide (GMP), a milk-derived peptide, holds promise because it can modulate the gut microbiome, immune responses, gut motility, and barrier functions, as well as binding toxins. These properties align with the recognized pathophysiological aspects of IBS, including gut microbiota imbalances, immune system dysregulation, and altered gut barrier functions. This review delves into GMP's role in regulating the gut microbiome, accentuating its influence on bacterial populations and its potential to promote beneficial bacteria while inhibiting pathogenic varieties. It further investigates the gut microbial shifts observed in IBS patients and contemplates GMP's potential for restoring microbial equilibrium and overall gut health. The anti-inflammatory attributes of GMP, especially its impact on vital inflammatory markers and capacity to temper the low-grade inflammation present in IBS are also discussed. In addition, this review delves into current research on GMP's effects on gut motility and barrier integrity and examines the changes in gut motility and barrier function observed in IBS sufferers. The overarching goal is to assess the potential clinical utility of GMP in IBS management.

Chinese herbal medicine versus antispasmodics in the treatment of irritable bowel syndrome: A network meta-analysis

BACKGROUND

Chinese herbal medicine (CHM) is gaining popularity in treating irritable bowel syndrome (IBS). Although its efficacy was shown in recent randomized controlled trials (RCTs), it is rarely compared with antispasmodics to confirm its effectiveness. We aimed to resolve this uncertainty through a network meta-analysis.

METHODS

We searched for RCTs that compared CHM or antispasmodics with placebo or one of them in the treatment of IBS. The primary outcomes were adequate relief of global IBS symptoms and abdominal pain. The data were pooled using a random-effects model. The effect size measure was pooled relative risk (RR), and treatments were ranked according to their P-scores.

KEY RESULTS

We included 57 RCTs (n = 8869). After completion of treatment, drotaverine, individual CHM, otilonium, cimetropium, standard CHM, and pinaverium were efficacious in adequate relief of global IBS symptoms, and drotaverine ranked the first (RR, 2.33 [95% CI, 1.31-4.14], P-score =0.91); no difference was found between these treatments. After completion of treatment, drotaverine, standard CHM, pinaverium, and individual CHM were efficacious in abdominal pain, and drotaverine ranked the first (RR, 2.71 [95% CI, 1.69-4.36], P-score =0.91); no difference was found between these treatments. Standard CHM had significantly more adverse events than placebo (RR, 1.82 [95% CI, 1.12-2.94]) and other treatments.

CONCLUSIONS

CHM and antispasmodics were efficacious for improvement of global IBS symptoms and abdominal pain. The adverse events of CHM were higher than antispasmodics; however, the heterogeneity of CHM formulas and the very low quality of the evidence warrants further investigation.

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.

Evidence-based clinical practice guidelines for irritable bowel syndrome 2020

Managing irritable bowel syndrome (IBS) has attracted international attention because single-agent therapy rarely relieves bothersome symptoms for all patients. The Japanese Society of Gastroenterology (JSGE) published the first edition of evidence-based clinical practice guidelines for IBS in 2015. Much more evidence has accumulated since then, and new pharmacological agents and non-pharmacological methods have been developed. Here, we report the second edition of the JSGE-IBS guidelines comprising 41 questions including 12 background questions on epidemiology, pathophysiology, and diagnostic criteria, 26 clinical questions on diagnosis and treatment, and 3 questions on future research. For each question, statements with or without recommendations and/or evidence level are given and updated diagnostic and therapeutic algorithms are provided based on new evidence. Algorithms for diagnosis are requisite for patients with chronic abdominal pain or associated symptoms and/or abnormal bowel movement. Colonoscopy is indicated for patients with one or more alarm symptoms/signs, risk factors, and/or abnormal routine examination results. The diagnosis is based on the Rome IV criteria. Step 1 therapy consists of diet therapy, behavioral modification, and gut-targeted pharmacotherapy for 4 weeks. For non-responders, management proceeds to step 2 therapy, which includes a combination of different mechanistic gut-targeted agents and/or psychopharmacological agents and basic psychotherapy for 4 weeks. Step 3 therapy is for non-responders to step 2 and comprises a combination of gut-targeted pharmacotherapy, psychopharmacological treatments, and/or specific psychotherapy. These updated JSGE-IBS guidelines present best practice strategies for IBS patients in Japan and we believe these core strategies can be useful for IBS diagnosis and treatment globally.

Pharmacological Therapies and Their Clinical Targets in Irritable Bowel Syndrome With Diarrhea

Irritable bowel syndrome (IBS) is one of the most common disorders of the gut-brain axis, which affects approximately 4% of the global population. The Rome IV criteria define IBS as chronic or recurrent abdominal pain associated with altered bowel habits. Patients can be categorized in four subtypes: IBS with predominant constipation (IBS-C), predominant diarrhea (IBS-D), mixed bowel habits (IBS-M), and unclassified (IBS-U). IBS is associated with a lower quality of life, reduced work productivity, and high healthcare costs. When comparing subtypes, patients with IBS-D report lower disease related quality of life. Due to the scope of this review, we have solely focused on patients with IBS-D. Choosing the right pharmacological treatment in these patients remains challenging due to the heterogeneous patient population, patients' expectation of the treatment outcome, unavailability of efficacious drugs, and the multifactorial and incompletely understood underlying pathophysiology. Currently, pharmacological treatment options target individual symptoms, such as abdominal pain, altered bowel habits, and bloating. In this review, we aimed to summarize the current and recent pharmacological treatment options in IBS-D, targeting the predominant gastrointestinal symptoms. Additionally, we proposed a pharmacological treatment algorithm which healthcare professionals could use when treating individual patients with 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.

Choi C, Kim SJ, Nam HS, Ryu DG, Hong JB, Kim DJ. Cimetropium bromide does not improve polyp and adenoma detection during colonoscope withdrawal: A randomized, double-blind, placebo-controlled study

BACKGROUND

Endoscopic inspection of colonic mucosa is disturbed by colonic folds and peristalsis, which may result in missed polyps. Cimetropium bromide, an antispasmodic agent, inhibits peristalsis and colonic spasms, which may improve polyp detection. The purpose of this randomized, double-blind, placebo-controlled study was to investigate whether cimetropium bromide could improve polyp and adenoma detection in the colorectum and right colon.

METHODS

Patients undergoing screening or diagnostic colonoscopy were randomized to receive intravenous cimetropium bromide (5 mg) or placebo after cecal intubation. The primary outcomes were the number of polyps per patient (PPP) and adenomas per patient (APP); secondary outcomes were the polyp detection rate (PDR), adenoma detection rate (ADR), and advanced neoplasm detection rate (ANDR).

RESULTS

A total of 181 patients were analyzed; 91 patients received cimetropium bromide and 90 patients received placebo. Cimetropium bromide and placebo groups did not significantly differ in the PPP and APP for the colorectum (1.38 ± 1.58 vs 1.69 ± 2.28, P = .298; 0.96 ± 1.27 vs 1.11 ± 1.89, P = .517, respectively) and right colon (0.70 ± 0.95 vs 0.78 ± 1.21, P = .645; 0.47 ± 0.81 vs 0.51 ± 0.81, P = .757, respectively). Two groups also did not significantly differ in the PDR, ADR, and ANDR for the colorectum and right colon. Furthermore, there were no difference between groups in the PPP, APP, PDR, ADR, and ADNR in a sub-analysis of expert and non-expert endoscopists.

CONCLUSIONS

Cimetropium bromide did not improve polyp and adenoma detection in the colorectum and right colon during colonoscope withdrawal, regardless of the expertness of the endoscopist. However, its use may be helpful in patients with active peristalsis or for beginning endoscopists during standard colonoscopy without a transparent cap.

Abdominal bloating: pathophysiology and treatment

Abdominal bloating is a very common and troublesome symptom of all ages, but it has not been fully understood to date. Bloating is usually associated with functional gastrointestinal disorders or organic diseases, but it may also appear alone. The pathophysiology of bloating remains ambiguous, although some evidences support the potential mechanisms, including gut hypersensitivity, impaired gas handling, altered gut microbiota, and abnormal abdominal-phrenic reflexes. Owing to the insufficient understanding of these mechanisms, the available therapeutic options are limited. However, medical treatment with some prokinetics, rifaximin, lubiprostone and linaclotide could be considered in the treatment of bloating. In addition, dietary intervention is important in relieving symptom in patients with bloating.

IBS and the role of otilonium bromide

INTRODUCTION

Awareness of the seriousness of irritable bowel disorder (IBS) remains low among clinicians. In this review, we summarize the current knowledge of IBS and highlight the major personal, economic, and social burden of the disease, and the importance of adequate treatment of what is still often viewed as a trivial disorder. In fact, IBS is a major reason for referral.

PATHOPHYSIOLOGY

It is crucial that the varied pathophysiologies of this complex heterogeneous disease are understood in order to be able to treat both the presenting symptoms (pain, bloating, flatulence, abnormal defecation, diarrhea, constipation) and the underlying disorder effectively. Low-grade inflammatory and immune activation has been observed, but the precise triggers and mechanisms, and the relevance to symptom generation, remain to be established.

TREATMENT

IBS patients require different treatment strategies according to the pattern, severity, frequency, and symptoms. While initial therapy traditionally targets the most bothersome symptom, long-term therapy aims at maintaining symptom control and preventing recurrence. In addition to dietary/lifestyle interventions and psychosocial strategies, a wide range of pharmacologic therapies are approved for use in IBS depending on the symptoms reported. Musculotropic spasmolytics, which act directly on intestinal smooth muscle contractility, such as otilonium bromide, are effective, particularly in the relief of abdominal pain and bloating, and are well tolerated in IBS. THE OBIS TRIAL: The recent large placebo-controlled Otilonium Bromide in Irritable Bowel Syndrome study demonstrated the superiority of otilonium bromide versus placebo not only in the reduction of pain and bloating, but also in protection from relapse due to the long-lasting effect.

Incidence of propofol injection pain and effect of lidocaine pretreatment during upper gastrointestinal endoscopy

BACKGROUND/AIMS

Propofol has been used in the past for sedation in upper gastrointestinal (GI) endoscopic procedures. This study aimed to measure the incidence of propofol injection pain and evaluate the effect of lidocaine on pain caused during sedative upper GI endoscopic examinations.

METHODS

Subjects scheduled to undergo sedative diagnostic upper GI endoscopy were randomly assigned to lidocaine and placebo groups. Pretreatment with a bolus of 1% lidocaine 2 ml or normal saline 2 ml into the largest dorsal vein of the non-dominant hand was followed by propofol administration. Pain intensity was estimated by an examiner blinded to the group assignment using a four-point verbal rating scale. A score of 1-3 was regarded as pain.

RESULTS

A total of 121 patients (males, 69; age, 58.6 ± 12.1 years) completed the study; 61 and 60 subjects were randomly assigned to the lidocaine and placebo groups, respectively. The incidence of pain during upper GI endoscopy was 60%. The lidocaine group showed a lower incidence of pain than the placebo group (37.7% vs. 60.0%, P = 0.018). The lidocaine group perceived significantly less pain than the placebo group (median pain score, 0 vs. 1, P = 0.008). Only lidocaine pretreatment was an independently associated factor against pain perception (OR, 0.380; 95% CI, 0.177-0.815; P = 0.013).

CONCLUSIONS

Pretreatment using lidocaine was found to be effective in reducing propofol injection-induced pain. However, its usefulness for GI endoscopic procedures in daily clinical practice needs further evaluation because of the low intensity of pain.

Bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder. The role of pharmacotherapy for IBS is limited and focused mainly on symptom control.

OBJECTIVES

The objective of this systematic review was to evaluate the efficacy of bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome.

SEARCH STRATEGY

Computer assisted structured searches of MEDLINE, EMBASE, The Cochrane library, CINAHL and PsychInfo were conducted for the years 1966-2009. An updated search in April 2011 identified 10 studies which will be considered for inclusion in a future update of this review.

SELECTION CRITERIA

Randomized controlled trials comparing bulking agents, antispasmodics or antidepressants with a placebo treatment in patients with irritable bowel syndrome aged over 12 years were considered for inclusion. Only studies published as full papers were included. Studies were not excluded on the basis of language. The primary outcome had to include improvement of abdominal pain, global assessment or symptom score.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from the selected studies. Risk Ratios (RR) and Standardized Mean Differences (SMD) with 95% confidence intervals (CI) were calculated. A proof of practice analysis was conducted including sub-group analyses for different types of  bulking agents, spasmolytic agents or antidepressant medication. This was followed by a proof of principle analysis where only the studies with adequate allocation concealment were included.

MAIN RESULTS

A total of 56 studies (3725 patients) were included in this review. These included 12 studies of bulking agents (621 patients), 29 of antispasmodics (2333 patients), and 15 of antidepressants (922 patients). The risk of bias was low for most items. However, selection bias is unclear for many of the included studies because the methods used for randomization and allocation concealment were not described. No beneficial effect for bulking agents over placebo was found for improvement of abdominal pain (4 studies; 186 patients; SMD 0.03; 95% CI -0.34 to 0.40; P = 0.87), global assessment (11 studies; 565 patients; RR 1.10; 95% CI 0.91 to 1.33; P = 0.32) or symptom score (3 studies; 126 patients SMD -0.00; 95% CI -0.43 to 0.43; P = 1.00). Subgroup analyses for insoluble and soluble fibres also showed no statistically significant benefit. Separate analysis of the studies with adequate concealment of allocation did not change these results. There was a beneficial effect for antispasmodics over placebo for improvement of abdominal pain (58% of antispasmodic patients improved compared to 46% of placebo; 13 studies; 1392 patients; RR 1.32; 95% CI 1.12 to 1.55; P < 0.001; NNT = 7), global assessment (57% of antispasmodic patients improved compared to 39% of placebo; 22 studies; 1983 patients; RR 1.49; 95% CI 1.25 to 1.77; P < 0.0001; NNT = 5) and symptom score (37% of antispasmodic patients improved compared to 22% of placebo; 4 studies; 586 patients; RR 1.86; 95% CI 1.26 to 2.76; P < 0.01; NNT = 3). Subgroup analyses for different types of antispasmodics found statistically significant benefits for cimteropium/ dicyclomine, peppermint oil, pinaverium and trimebutine. Separate analysis of the studies with adequate allocation concealment found a significant benefit for improvement of abdominal pain. There was a beneficial effect for antidepressants over placebo for improvement of abdominal pain (54% of antidepressants patients improved compared to 37% of placebo; 8 studies; 517 patients; RR 1.49; 95% CI 1.05 to 2.12; P = 0.03; NNT = 5), global assessment (59% of antidepressants patients improved compared to 39% of placebo; 11 studies; 750 patients; RR 1.57; 95% CI 1.23 to 2.00; P < 0.001; NNT = 4) and symptom score (53% of antidepressants patients improved compared to 26% of placebo; 3 studies; 159 patients; RR 1.99; 95% CI 1.32 to 2.99; P = 0.001; NNT = 4). Subgroup analyses showed a statistically significant benefit for selective serotonin releasing inhibitors (SSRIs) for improvement of  global assessment and for tricyclic antidepressants (TCAs) for improvement of abdominal pain and symptom score. Separate analysis of studies with adequate allocation concealment found a significant benefit for improvement of symptom score and global assessment. Adverse events were not assessed as an outcome in this review.

AUTHORS' CONCLUSIONS

There is no evidence that bulking agents are effective for treating IBS.  There is evidence that antispasmodics are effective for the treatment of IBS. The individual subgroups which are effective include: cimetropium/dicyclomine, peppermint oil, pinaverium and trimebutine. There is good evidence that antidepressants are effective for the treatment of IBS. The subgroup analyses for SSRIs and TCAs are unequivocal and their effectiveness may depend on the individual patient. Future research should use rigorous methodology and valid outcome measures.

[Guidelines for the treatment of irritable bowel syndrome]

Traditional symptom-based therapies of irritable bowel syndrome (IBS) are directed at the relief of individual IBS symptoms, but they are often of limited efficacy in addressing the entire symptom complex. Combinations of drugs to target bothersome symptoms are suggested as the first-line pharmacologic treatment. Increasing knowledge of the pathophysiology and molecular mechanisms of IBS has resulted in the development of several new therapeutic approaches. Thirteen consensus statements for the treatment of IBS were developed using the modified Delphi approach. Exclusion diets have modest efficacy in improving symptoms in some IBS patients. Symptom-based therapies with dietary fiber, bulking agents, laxatives, antispasmodics and laxatives are effective in the improvement of some individual symptoms, e.g. dietary fiber and bulking agents for constipation, laxatives for constipation, antispasmodics for abdominal pain and discomfort, antidiarrheals for diarrhea. 5HT3 receptor antagonists and 5HT((4)) receptor agonists are effective in the relief of global IBS symptoms and individual symptoms such as abdominal pain and abnormal bowel habits. A short term course of nonabsorbable antibiotics may improve global IBS symptoms, particularly in patients with diarrhea- predominant IBS. Some probiotics appear to have the potential benefit in improving global IBS symptoms. Selective C-2 chloride channel activator is more effective than placebo at relieving global IBS symptoms in patients with constipation-predominant IBS. Both tricyclic antidepressants and selective serotonin reuptake inhibitors are equally effective in relieving global IBS symptoms, and have some benefits in treating abdominal pain. Certain types of psychologic therapy may be effective in improving global symptoms in some IBS patients. Further studies are strongly needed to develop better treatment strategies for Korean patients with IBS.

Meta-analysis: factors affecting placebo response rate in the irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract with a significant placebo response.

AIM

To conduct a systematic review and meta-analysis examining the magnitude of placebo response rate in treatment trials for IBS.

METHODS

MEDLINE, EMBASE and the Cochrane central register of controlled trials were searched to identify randomized controlled trials (RCTs) comparing pharmacological therapies with placebo in adult IBS patients. Studies reported either global assessment of IBS symptom cure or improvement or abdominal pain cure or improvement. Data were extracted as intention-to-treat analyses with drop-outs assumed to be treatment failures and pooled using a random-effects model. Proportion of placebo patients experiencing symptom improvement or resolution was reported with a 95% confidence interval (CI). Effect of trial characteristics on magnitude of placebo response was examined.

RESULTS

In all, 73 RCTs were eligible, including 8364 patients with IBS allocated to placebo. Pooled placebo response rate across all RCTs was 37.5% (95% CI 34.4-40.6%). Rates were higher in European RCTs, RCTs that used physician-reported outcomes and RCTs using shorter duration of therapy.

CONCLUSIONS

Placebo response rates across RCTs of pharmacological therapies in IBS were high. Future research should identify patient characteristics predicting placebo response.

Systematic review: the efficacy of treatments for irritable bowel syndrome--a European perspective

BACKGROUND

Irritable bowel syndrome (IBS) is a common, chronic disorder, characterized by abdominal pain/discomfort, bloating and altered bowel habit.

AIM

To conduct a systematic evidence-based review of pharmacological therapies currently used, or in clinical development, for the treatment of IBS in Europe. The safety and tolerability of these therapies are the subject of an accompanying review.

METHODS

A literature search was completed for randomized controlled studies which included adult patients with IBS and an active or placebo control, assessed IBS symptoms, and were published in English between January 1980 and June 2005. The level of evidence for efficacy was graded according to the quality of the trial design and the study outcome.

RESULTS

There is some evidence for improvement of individual IBS symptoms with antidiarrhoeals (diarrhoea), antispasmodics (abdominal pain/discomfort), bulking agents (constipation), tricyclic antidepressants (abdominal pain/discomfort) and behavioural therapy. In contrast, there is strong evidence for the improvement of global IBS symptoms with two new serotonergic agents: the 5-HT4 selective agonist tegaserod (IBS with constipation) and the 5-HT3 antagonist alosetron (IBS with diarrhoea). Further data are required for the 5-HT3 antagonist, cilansetron, and the mixed 5-HT3 antagonist/5-HT4 agonist renzapride before their utility in IBS can be appraised.

CONCLUSIONS

There is limited evidence for the efficacy, safety and tolerability of therapies currently available in Europe for the treatment of IBS. Overall, there is an absence of pharmacological agents licensed specifically for the treatment of IBS subtypes, and new agents are awaited in Europe that will allow changes in clinical practice to focus on and improve global IBS symptoms.

Systematic review: the safety and tolerability of pharmacological agents for treatment of irritable bowel syndrome--a European perspective

AIM

To use an evidence-based approach to evaluate the safety and tolerability of the treatments available for irritable bowel syndrome (IBS), or in clinical development, in Europe. A separate review appraises the evidence for the efficacy of these therapies.

METHODS

A literature search (for 1980 to 2005) was completed for all relevant clinical trial data and other articles which included safety information on the use of pharmacological IBS therapies. Clinical trials were scored according to the level of safety information, and adverse event incidence reported when possible.

RESULTS

The tolerability of many of the agents used to treat IBS in Europe is poorly understood. However, serotonergic agents, such as tegaserod and alosetron, which are currently unavailable in Europe, have undergone rigorous assessment in IBS and their benefits have been established. Following initial marketing of alosetron for use in patients with IBS with diarrhoea, concerns about severe constipation and ischaemic colitis resulted in restriction of its use to women with severe IBS symptoms. This highlights the importance of post-marketing surveillance and post-marketing studies in refining the therapeutic indication of new IBS therapies, which will help to identify appropriate recipients for the drug and establish the impact of adverse reactions in clinical practice.

CONCLUSIONS

There is a significant lack of data on the safety and tolerability of the therapies currently used routinely to treat IBS in Europe. The newer agents have undergone rigorous assessment, such that their benefits and risks in treating IBS are established. Defining their place among the spectrum of available therapies remains challenging when the benefits and risks of the older treatments are so poorly characterized.

The placebo effect in irritable bowel syndrome trials: a meta-analysis

BACKGROUND

Despite the apparent high placebo response rate in randomized placebo-controlled trials (RCT) of patients with irritable bowel syndrome (IBS), little is known about the variability and predictors of this response.

OBJECTIVES

To describe the magnitude of response in placebo arms of IBS clinical trials and to identify which factors predict the variability of the placebo response.

METHODS

We performed a meta-analysis of published, English language, RCT with 20 or more IBS patients who were treated for at least 2 weeks. This analysis is limited to studies that assessed global response (improvement in overall symptoms). The variables considered as potential placebo modifiers were study design, study duration, use of a run-in phase, Jadad score, entry criteria, number of office visits, number of office visits/study duration, use of diagnostic testing, gender, age and type of medication studied.

FINDINGS

Forty-five placebo-controlled RCTs met the inclusion criteria. The placebo response ranged from 16.0 to 71.4% with a population-weighted average of 40.2%, 95% CI (35.9-44.4). Significant associations with lower placebo response rates were fulfillment of the Rome criteria for study entry (P=0.049) and an increased number of office visits (P=0.026).

CONCLUSIONS

Placebo effects in IBS clinical trials measuring a global outcome are highly variable. Entry criteria and number of office visits are significant predictors of the placebo response. More stringent entry criteria and an increased number of office visits appear to independently decrease the placebo response.

Efficacy of current drug therapies in irritable bowel syndrome: what works and does not work

Based on current evidence, bulking agents are not more effective than placebo at improving global irritable bowel syndrome (IBS)symptoms, although they may increase stool frequency in large doses. Tricyclic antidepressants are more effective than placebo for patients with diarrhea-predominant IBS. Imodium is more effective than placebo at improving stool consistency and decreasing stool frequency in patients with IBS, and it may be an important component for treating diarrhea-predominant IBS. Antispasmodics agents available in the United States are not more effective than placebo for treating IBS, although the studies are small and poorly designed. There are no randomized controlled trials examining the efficacy of laxatives for managing IBS. Tegaserod is more effective than placebo at improving global IBS symptoms in women with nondiarrhea-predominant IBS. Alosetron is more effective than placebo in women with diarrhea-predominant IBS, although its use should be limited to patients who have failed conventional therapy because of its adverse event profile.

Bulking agents, antispasmodic and antidepressant medication for the treatment of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common health problem, often presenting in primary care as well as in internal medicine and gastroenterology outpatient clinics. Therapeutic options are dominated by drug therapies but there is uncertainty about their effectiveness.

OBJECTIVES

The primary objective of this review was to evaluate the efficacy of bulking agents, antispasmodic and antidepressant medication for the treatment of IBS.

SEARCH STRATEGY

A computer assisted search of MEDLINE, EMBASE, PsychInfo and the Cochrane Library was performed for the years 1966-2001; local and national databases were searched in 10 European countries.

SELECTION CRITERIA

Randomised trials comparing bulking agents, antispasmodic or antidepressant medications with a placebo, in IBS patients over 12 years of age. Only studies published as a full paper were included. No language criterion was applied.

DATA COLLECTION AND ANALYSIS

The search identified 687 studies, 66 of which fulfilled all eligibility criteria. After removal of cross-over studies that did not report separately on the first phase, data from 40 studies remained for analysis. Relative risk (RR), risk difference (RD) and standardized mean difference (SMD) along with 95% confidence intervals were calculated for all subgroups. The number needed to treat (NNT) was also calculated where appropriate.

MAIN RESULTS

Forty-one study reports from 40 studies, comprising 78 comparisons, were analysed. These included 11 reports on bulking agents, 6 on antidepressants, and 24 on spasmolytics.BULKING AGENTS: Three studies comprising 159 patients reported a dichotomous outcome for relief of abdominal pain. The pooled RR using a random effects model was 1.22 (95% CI 0.86 - 1.73). Three studies comprising 128 patients reported a continuous outcome for relief of abdominal pain. Using the random effects model, the SMD was 0.68 (95% CI -0.86 - 2.33). Nine studies comprising 482 patients reported a dichotomous outcome for global assessment of improvement. The pooled RR was 1.09 (95% CI 0.78 - 1.50). Five studies comprising 253 patients reported a dichotomous outcome for improvement of symptom score. The pooled RR using a random effects model was 0.93 (95% CI 0.56 - 1.54). Two studies comprising 70 patients reported a continuous outcome for improvement of symptom score; the SMD using a fixed effects model was -0.44 (95% CI -1.20 - 0.31). SPASMOLYTIC AGENTS: Eleven studies comprising 1260 patients reported a dichotomous outcome for relief of abdominal pain. The pooled RR using a random effects model was 1.34 (95% CI 1.13 - 1.59; RD=0.17, 95% CI 0.06 -0.28; NNT=6, 95% CI 4 - 15). Seven studies comprising 467 patients reported a continuous outcome for relief of abdominal pain. Using a fixed effects model the pooled SMD was -0.65 (95% CI -0.94 to -0.35). Sixteen studies comprising 1236 patients reported a dichotomous outcome for global assessment of improvement. The pooled RR using a random effects model was 1.42 (95% CI 1.17 - 1.72; RD=0.20, 95% CI 0.09 -0.30; NNT=5, 95% CI 3 - 11). One study comprising 34 patients reported a dichotomous variable for improvement of symptom score. The RR was 1.33 (95% CI 0.96 - 1.85). Three studies reported a continuous outcome for improvement of symptom score; two studies comprising 66 patients could be pooled. Using a fixed effects model, the SMD was -0.37 (95% CI -0.85 - 0.12). ANTIDEPRESSANTS: Two studies comprising 81 patients reported a dichotomous outcome for relief of abdominal pain. Using the random effects model, the pooled RR was 0.83 (95% CI 0.33 - 2.12). Two studies comprising 101 patients reported a continuous outcome for relief of abdominal pain. The SMD using a random effects model was -0.53 (95% CI -2.29 - 1.23). Four studies comprising 241 patients reported a dichotomous variable for global assessment of improvement. The pooled RR was 1.16 (95% CI 0.78 - 1.73).

AUTHORS' CONCLUSIONS

The evidence for efficacy of drug therapies for IBS is weak. Although there is evidence of benefit for antispasmodic drugs for abdominal pain and global assessment of symptoms; it is unclear whether anti-spasmodic subgroups are individually effective. There is no clear evidence of benefit for antidepressants or bulking agents. The physician should be aware that global assessment is a construct containing various dimensions. For each individual, these will have a different weighting and treatment should be aimed at the most debilitating symptom. Stool problems are by definition part of the IBS symptom complex. Bulking agents may improve constipation and can be used empirically, but should be evaluated at an early stage for individual benefit. Future research should pay attention to study methodology and the use of valid outcome measures.

Meta-analysis: The treatment of irritable bowel syndrome

To evaluate therapies available for the treatment of irritable bowel syndrome, and provide consensus recommendations for their use, a total of 51 double-blind clinical trials using bulking agents, prokinetics, antispasmodics, alosetron, tegaserod and antidepressants were selected. The quality of studies was assessed using 5-point scale. Meta-analyses were performed on all studies, and on 'high-quality studies'. The efficacy of fibre in the global irritable bowel syndrome symptoms relief (OR: 1.9; 95% CI:1.5-2.4) was lost after exclusion of low-quality trials (OR: 1.4; 95% CI: 1.0-2.0, P = 0.06). When excluding the low-quality trials, an improvement of global irritable bowel syndrome symptoms with all antispasmodics (OR: 2.1; 95% CI:1.8-2.9) was maintained only for octylonium bromide, but on the basis of only two studies. Antidepressants were effective (OR: 2.6, 95% CI: 1.9-3.5), even after exclusion of low-quality studies (OR: 1.9, 95% CI: 1.3-2.7). Alosetron (OR: 2.2; 95% CI: 1.9-2.6) and tegaserod (OR: 1.4; 95% CI: 1.2-1.5) showed a significant effect in women. We recommend the use of tegaserod for women with irritable bowel syndrome with constipation and alosetron for women with severe irritable bowel syndrome with diarrhoea. Antidepressants can be beneficial for irritable bowel syndrome with diarrhoea patients with severe symptoms. Loperamide can be recommended in painless diarrhoea. Evidence is weak to recommend the use of bulking agents in the treatment of irritable bowel syndrome with constipation.

Benefit-Risk Assessment of Tegaserod in Irritable Bowel Syndrome

Tegaserod is a new partial agonist of serotonin 5-HT4 receptors specifically developed for the treatment of nondiarrhoeal forms of irritable bowel syndrome (IBS). Among its various effects is the stimulation of the peristaltic reflex with its promotility action appearing to affect the whole length of the gastrointestinal tract. Tegaserod has been assessed in a number of international multicentre trials and its use leads to an improvement in abdominal pain and bowel dysfunction as well as global well-being, at the expense of remarkably few adverse effects. It is noteworthy that it also appears to improve bloating, a benefit that has not been previously reported for a medication used in IBS. The optimal dose is 6 mg twice daily and the advantage of tegaserod over placebo in different trials varies from 5-20% with the number needed to treat ranging from 5-15 depending on the time at which this effect is calculated during the course of a trial. Recent experience with other drugs acting on 5-HT receptors has focused attention on possible safety issues such as prolongation of the QTc interval on the electrocardiogram and ischaemic colitis. However, data from efficacy trials and studies specifically designed to address the safety of tegaserod have not revealed any evidence of cardiotoxicity or the potential for causing ischaemic colitis. Furthermore, investigation of possible interactions with other drugs such as warfarin or the oral contraceptive have not resulted in any prescribing restrictions. Inappropriate prescription of tegaserod to a subgroup of IBS patients for which the drug was not designed, does not appear to have any serious consequences. Most of the efficacy data on tegaserod has been accumulated in females, simply as a result of the failure to recruit adequate numbers of males or restriction of trials to females. There is therefore insufficient information to assess whether there might be any potential gender differences in responsiveness. For this reason, the drug is currently only licensed for use in females.

Evaluation of drug treatment in irritable bowel syndrome

The irritable bowel syndrome (IBS) remains a therapeutic challenge in part because of the limited understanding of the pathophysiology. The placebo response rate varies in randomized controlled trials from 20 to 70%, and can persist for up to at least 1 year. It is contentious whether dietary fibre and bulking agents relieve the symptoms of IBS; constipation probably improves. Anticholinergic and antispasmodic agents are of questionable benefit in IBS despite positive meta-analyses of poor quality trials. A meta-analysis concluded that the tricyclic antidepressants were superior to placebo in IBS, although the individual trial results were variable. Selective serotonin reuptake inhibitors are of uncertain benefit. Laxatives are used for constipation but probably poorly control the IBS symptom complex. Loperamide is superior to placebo in improvement of diarrhoea but not abdominal pain in IBS. Tegaserod is a well- tolerated aminoguanidine indole derivative of serotonin that is a partial 5HT4-receptor agonist with prokinetic properties; a therapeutic gain over placebo of 5% to 15% has been observed in constipation-predominant IBS in females. Alosetron is a 5HT3-receptor antagonist that is efficacious in females with diarrhoea-predominant IBS, with a 12% to 17% therapeutic gain; the risk of ischaemic colitis is 1 in 350, with very severe constipation occurring in about 1 in 1000. Optimizing study design remains a challenge in IBS. New visceral analgesic and motility modifying agents, as well as anti-inflammatory agents are in trials, and hopefully additional efficacious therapeutic options for patients with IBS will soon emerge.

Comorbidity of irritable bowel syndrome in psychiatric patients: a review

Irritable bowel syndrome (IBS), a functional gastrointestinal disorder, is present in 10% to 20% of the U.S. adult population. The syndrome is best defined as chronic abdominal discomfort with changes in stool frequency, consistency, and passage, with associated symptoms such as abdominal bloating or presence of mucus in stools. Several studies have shown that up to 70% to 90% of patients with IBS who seek treatment have psychiatric comorbidity, most notably mood and anxiety disorders. Recent studies have shown a high prevalence of IBS in psychiatric patients who seek treatment, with a prevalence of 19% in schizophrenia, 29% in major depression, and 46% in panic disorder among other disorders. Our article reviews the comorbidity of IBS in psychiatric patients and discusses implications for treatment.

Long-term safety of tegaserod in patients with constipation-predominant irritable bowel syndrome

BACKGROUND

Tegaserod is a 5-hydroxytryptamine-4 receptor partial agonist. Oral administration causes gastrointestinal effects resulting in increased gastrointestinal motility and attenuation of visceral sensation.

AIM

: To determine the long-term safety and tolerability of tegaserod in patients suffering from irritable bowel syndrome with constipation as the predominant symptom of altered bowel habits.

METHOD

A multicentre, open-label study with flexible dose titration of tegaserod in out-patients suffering from constipation-predominant irritable bowel syndrome.

RESULTS

A total of 579 patients with constipation-predominant irritable bowel syndrome were treated with tegaserod. Of these, 304 (53%) completed the trial. The most common adverse events, classified as related to tegaserod for any dose, were mild and transient diarrhoea (10.1%), headache (8.3%), abdominal pain (7.4%) and flatulence (5.5%). Forty serious adverse events were reported in 25 patients (4.4% of patients) leading to discontinuation in six patients. There was one serious adverse event, acute abdominal pain, classified as possibly related to tegaserod. There were no consistent differences in adverse events between patients previously exposed to tegaserod and those treated de novo. No pattern-forming tegaserod-related abnormalities in haematological and biochemical laboratory tests, urinalysis, blood pressure, pulse rate or electrocardiograms were found.

CONCLUSIONS

Tegaserod appears to be well tolerated in the treatment of patients with constipation-predominant irritable bowel syndrome. The adverse event profile, clinical laboratory evaluations, vital signs and electrocardiogram recordings revealed no evidence of any unexpected adverse events, and suggest that treatment is safe over a 12-month period.

The treatment of irritable bowel syndrome

The efforts of clinical researchers, lay organizations and pharmaceutical companies have increased the public profile of irritable bowel syndrome and made it a respectable diagnosis. Diagnostic symptom criteria encourage a firm clinical diagnosis, which is the foundation of a logical management strategy. This begins with education. Reassurance that no structural disease threatens should be tempered with the reality that symptoms are likely to recur over many years. Patients expect diet and lifestyle advice, even if this is not specific to irritable bowel syndrome. Only a few of those with irritable bowel syndrome see doctors, and even fewer see specialists. Therefore, the treating physician should ascertain the reason for the visit, the patient's fears and the presence of any comorbid illness, such as depression, that might require treatment in its own right. No drug treatment is useful for all of the symptoms of irritable bowel syndrome, and many patients require no drug at all. If used, drugs should target the predominant symptom. Alosetron, a 5-HT3 antagonist, is effective in treating women with irritable bowel syndrome who also have diarrhoea. Tegaserod, a 5-HT4 agonist, is useful for women with irritable bowel syndrome who are constipated. Most patients with irritable bowel syndrome need psychological support. Reassurance, discussion and relaxation techniques can be provided by the family doctor. Difficult psychopathology may require referral to a mental health professional, and the gastroenterologist can settle diagnostic uncertainties. In all cases, successful treatment depends on a confident diagnosis and the strength of the doctor-patient relationship.

Irritable bowel syndrome

Irritable bowel syndrome is a biopsychosocial disorder characterized by dysregulation of intestinal motor, sensory, and central nervous system functions. It is associated with significant disability and health-care costs. The traditional diagnostic approach leads to excessive investigation for many patients. A reductionist approach of focusing on evaluation and treatment of a single mechanism is unlikely to prove effective. Identification of the characteristic symptom pattern is the key to cost-effective management. A strong patient-physician relationship is essential for a successful outcome. Optimal outcome is predicated on an individualized treatment plan that integrates pharmacologic and behavioral modalities.

Diarrhea- and Constipation-predominant Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) has a reputation for being hard to treat, trivial, and often psychologic in origin. Furthermore, there currently appears to be almost more of a stigma attached to being diagnosed as having IBS than a depressive illness. Thus, it is not surprising that patients with this syndrome become distressed by the attitudes they encounter, particularly as we now know that this condition can substantially impair one's quality of life. The problem with effective management is that there is no "standard treatment" and therapy has to be targeted to the symptoms of the individual patient. This frequently proves to be time consuming and also may involve some degree of trial and error. However, when all the issues surrounding IBS are addressed in a sympathetic and positive manner, these patients can be surprisingly rewarding to treat.

Meta-analysis of smooth muscle relaxants in the treatment of irritable bowel syndrome

AIM

To update previous overviews of placebo-controlled double-blind trials assessing the efficacy and tolerance of smooth muscle relaxants in irritable bowel syndrome. METHODS AND TRIALS: A total of 23 randomized clinical trials were selected for meta-analyses of their efficacy and tolerance. Six drugs were analysed: cimetropium bromide (five trials), hyoscine butyl bromide (three trials), mebeverine (five trials), otilium bromide (four trials), pinaverium bromide (two trials) and trimebutine (four trials). The total number of patients included was 1888, of which 945 received an active drug and 943 a placebo.

RESULTS

The mean percentage of patients with global improvement was 38% in the placebo group (n=925) and 56% in the myorelaxant group (n=927), in favour of myorelaxants with a mean odds ratio of 2.13, P < 0.001 (95% CI: 1.77--2.58) and a mean risk difference of 22% P < 0.001 (95% CI: 13--32%). The percentage of patients with pain improvement was 41% in the placebo group (n=568) and 53% in the myorelaxant group (n=567): odds ratio 1.65, P < 0.001 (95% CI: 1.30--2.10) and risk difference 18%, P < 0.001 (95% CI: 7--28%). There was no significant difference for adverse events.

CONCLUSION

Myorelaxants are superior to placebo in the management of irritable bowel syndrome.

Treatment of irritable bowel syndrome: a review of randomised controlled trials

Irritable bowel syndrome (IBS) is a common chronic disorder that is associated with significant disability and health care costs. The purpose of this paper is to review and assess published randomised controlled trials examining the clinical effectiveness of interventions for IBS for 1987-1998. A literature search was conducted to identify randomised controlled trials of IBS treatments: 45 studies were identified that described randomised controlled trials and of these, six fulfilled all three criteria used to assess the quality of randomised controlled trials, as described by Jadad and colleagues.(1) These criteria are: adequate description of randomisation, double blinding, and description of withdrawals and dropouts. It is concluded that there are few studies which offer convincing evidence of effectiveness in treating the IBS symptom complex. This review strongly suggests that future work should include well designed trials that: describe the randomisation method; use internationally approved diagnostic criteria; and are double blinded and placebo controlled. Clear well defined outcome measures are necessary. Inclusion of quality of life measures allows comparison between trials in different therapeutic areas. Conducting such studies will help to overcome some of the difficulties identified in this review.

Problems and challenges in the design of irritable bowel syndrome clinical trials: experience from published trials

The last two decades have seen many studies that are of inadequate design and power. This report focuses on what we have learned from the 25 randomized, controlled studies that included at least 30 patients during the period 1976-1998. The most important finding has been that the median placebo response was 47% (range, 0-84%), which is approximately three times the size of the difference between placebo and drug response, median 16% (range, -17-64%). This tells us the importance of reassurance and the powerful nonspecific therapeutic effects of entering patients into clinical trials in irritable bowel syndrome (IBS). Patients should be stratified according to the dominant symptoms that are relevant to the drug's intended effect. A randomized, double-blind, controlled, parallel group study appears the most robust design. Minimizing the placebo response reduces the numbers needed to detect a significant difference. The optimum length of trial is probably >3 months, because the placebo effect takes approximately 12 weeks to start to recede. Dose titration should maximize the chance of detecting a benefit.

Review article: clinical evidence to support current therapies of irritable bowel syndrome

This review summarizes the clinical evidence to support current therapies in irritable bowel syndrome (IBS). Fibre is indicated at a dose of at least 12 g per day in patients with constipation-predominant IBS. Loperamide (and probably other opioid agonists) are of proven benefit in diarrhoea-predominant IBS; loperamide may also aid continence by enhancing resting anal tone. In general, smooth muscle relaxants are best used sparingly, on an 'as needed' basis, as their overall efficacy is unclear. Psychotropic agents are important in relieving depression and of proven benefit for pain and diarrhoea in patients with depression associated with IBS. Further trials with selective serotonin reuptake inhibitors (SSRIs) are awaited. Psychological treatments including hypnotherapy are less widely available, but may play an important role in relief of pain. In summary, current therapies targeted on the predominant symptoms in IBS are moderately successful. New therapies are needed to more effectively relieve this syndrome, not just symptoms.

Otilonium bromide in irritable bowel syndrome: a double-blind, placebo-controlled, 15-week study

AIM

To evaluate the efficacy of otilonium bromide, a spasmolytic agent, in the treatment of irritable bowel syndrome using modern and validated diagnostic criteria.

METHODS

Three hundred and seventy-eight patients with irritable bowel syndrome were enrolled in the study. At entry, endoscopy/barium enema, clinical examination and laboratory tests were used to rule out organic diseases. After a 2-week placebo run-in, 325 patients were randomly assigned to receive either otilonium bromide 40 mg t.d.s. or placebo for 15 weeks. Abdominal pain, abdominal distension and disturbed defecation were scored at the beginning of the study and every 5 weeks. A global determination of well-being by visual analogue scale and the tenderness of the sigmoid colon were also scored.

RESULTS

The reduction in the number of abdominal pain episodes was significantly higher (P < 0.01) in otilonium bromide patients (55.3%) than in those taking placebo (39.9%) as was the severity of abdominal distension (42.0%, vs. 30.2%; P < 0.05). Bowel disturbance improved in both groups. but without any statistically significant difference. The visual analogue scale of well-being revealed a significant improvement (P < 0.05) in patients taking otilonium bromide. The investigators' global positive assessment was in favour of otilonium bromide (65.2%) compared with placebo (49.6%) (P < 0.01).

CONCLUSIONS

Otilonium bromide may represent an effective treatment for irritable bowel syndrome because it reduces its predominant symptom (abdominal pain/ discomfort) more than placebo does.

Effects of cisapride on symptoms and postcibal small-bowel motor function in patients with irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome is a common cause of abdominal pain and discomfort and may be related to disordered gastrointestinal motility. Our aim was to assess the effects of long-term treatment with a prokinetic agent, cisapride, on postprandial jejunal motility and symptoms in the irritable bowel syndrome (IBS).

METHODS

Thirty-eight patients with IBS (constipation-predominant, n = 17; diarrhoea-predominant, n = 21) underwent 24-h ambulatory jejunal manometry before and after 12 week's treatment [cisapride, 5 mg three times daily (n = 19) or placebo (n = 19)].

RESULTS

In diarrhoea-predominant patients significant differences in contraction characteristics were observed between the cisapride and placebo groups. In cisapride-treated diarrhoea-predominant patients the mean contraction amplitude was higher (29.3 +/- 3.2 versus 24.9 +/- 2.6 mm Hg, cisapride versus placebo (P < 0.001); pretreatment, 25.7 +/- 6.0 mm Hg), the mean contraction duration longer (3.4 +/- 0.2 versus 3.0 +/- 0.2 sec, cisapride versus placebo (P < 0.001); pretreatment, 3.1 +/- 0.5 sec), and the mean contraction frequency lower (2.0 +/- 0.2 versus 2.5 +/- 0.4 cont./min, cisapride versus placebo (P < 0.001); pretreatment, 2.5 +/- 1.1 cont./min] than patients treated with placebo. No significant differences in jejunal motility were found in the constipation-predominant IBS group. Symptoms were assessed by using a visual analogue scale before and after treatment. Symptom scores relating to the severity of constipation were lower in cisapride-treated constipation-predominant IBS patients [score, 54 +/- 5 versus 67 +/- 14 mm, cisapride versus placebo (P < 0.05); pretreatment, 62 +/- 19 mm]. Diarrhoea-predominant IBS patients had a higher pain score after cisapride therapy [score, 55 +/- 15 versus 34 +/- 12 mm, cisapride versus placebo (P < 0.05); pretreatment, 67 +/- 19 mm].

CONCLUSION

Cisapride affects jejunal contraction characteristics and some symptoms in IBS.

Review article: irritable bowel syndrome

Irritable bowel syndrome is a disease that can be diagnosed positively on the basis of an established series of criteria and limited exclusion of organic disease. It is the most common disease diagnosed by gastroenterologists and affects about 20% of all people at any one time. Symptoms fluctuate, and the overall prevalence rate is relatively constant in Western communities. Ten per cent of patients present to their physicians; the illness has a large economic impact on health-care utilization and absenteeism. Irritable bowel syndrome is a biopsychosocial disorder in which three major mechanisms interact: psychosocial factors; altered motility; and/or sensory function of the intestine. Management of patients is based on positive diagnosis of the symptom complex, limited exclusion of underlying organic disease and institution of a therapeutic trial. If patient symptoms are intractable, further investigations are needed to exclude significant motility or other disorders. Symptomatic treatment includes fibre for constipation, loperamide for diarrhoea and low-dose antidepressants or infrequent use of antispasmodics for pain; novel pharmacological agents, psychotherapy and hypnotherapy are being evaluated.

Therapeutic strategies for motility disorders. Medications, nutrition, biofeedback, and hypnotherapy

Gastrointestinal motility is regulated by a complex balance of inhibitory and excitatory neuronal, humoral, and mechanical factors. The goal in the management of motility disorders is to maintain adequate nutrition while decreasing symptoms. This can be accomplished by medications and support of nutrition and biofeedback; the application of these therapeutic strategies to patients with gut motility disorders is reviewed.

Irritable bowel syndrome. Managing the patient with abdominal pain and altered bowel habits

Irritable bowel syndrome is a common complex of syndromes thought to be generated by a motility or sensory disturbance of the gastrointestinal tract. It is a frequent cause of chronic abdominal pain and altered bowel habits. Patients who seek medical attention for irritable bowel syndrome often do so because of psychosocial factors. Therapy remains largely empirical, directed toward the relief of symptoms in the context of a supportive physician-patient relationship.

Meta-analysis of smooth muscle relaxants in the treatment of irritable bowel syndrome

AIM

To assess the efficacy of smooth muscle relaxants in the treatment of patients with irritable bowel syndrome, a meta-analysis of 26 selected double-blind randomized trials vs. placebo was performed.

METHODS

Five end-points were assessed: global assessment, abdominal pain, constipation, abdominal distension and the absence of adverse reactions. Analyses were performed according to the intention-to-treat method. For each end-point, the drug efficacy was assessed by the Der Simonian and Peto methods. When a significant difference was observed, sensitivity analyses were performed by successive stratifications according to the type of drug, the treatment duration, the prevalence of constipated patients, the trial design and the methodological quality.

RESULTS

All myorelaxants analysed were significantly better than placebo for the improvement of global assessment (62% improvement rate vs. 35% on placebo, that is 27% improvement rate, P < 0.01) and for pain improvement (64% improvement rate vs. 45% on placebo, that is 19% improvement rate, P < 0.01). No significant differences were observed for constipation and abdominal distension. The percentage of patients with adverse reactions was significantly higher in patients receiving myorelaxants than placebo (6% mean difference, P < 0.01).

CONCLUSION

According to this overview five drugs have proved their clinical efficacy in patients with irritable bowel syndrome, without significant adverse reactions: cimetropium bromide, pinaverium bromide, trimebutine, octilium bromide and mebeverine.