Efficacy of tandospirone in patients with irritable bowel syndrome-diarrhea and anxiety

Efficacy of gut-brain neuromodulators in irritable bowel syndrome: an updated systematic review and meta-analysis

BACKGROUND

Gut-brain neuromodulators might be efficacious for irritable bowel syndrome (IBS), but there has been no synthesis of evidence from randomised controlled trials (RCTs) of some drug classes, and whether they have pain-modifying properties in IBS is unclear. We updated a previous systematic review and meta-analysis of RCTs examining these questions.

METHODS

We searched MEDLINE (from Jan 1, 1946, to Jan 1, 2025), Embase and Embase Classic (from Jan 1, 1947, to Jan 1, 2025), and the Cochrane Central Register of Controlled Trials (from database inception to Jan 1, 2025). Trials recruiting adults with IBS and that compared gut-brain neuromodulators versus placebo over at least 4 weeks of treatment were eligible. Dichotomous symptom data were pooled using a random effects model to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% CI.

FINDINGS

The search strategy identified 3625 citations. 28 RCTs were eligible containing 2475 patients. Ten RCTs were identified since our previous meta-analysis, containing 1348 patients. The RR of global IBS symptoms not improving with gut-brain neuromodulators versus placebo in 22 RCTs (2222 patients) was 0·77 (95% CI 0·69-0·87). The best evidence in terms of persistence of global IBS symptoms was for tricyclic antidepressants (TCAs) in 11 trials (1144 patients; RR 0·70, 0·62-0·80). The RR of abdominal pain not improving with gut-brain neuromodulators versus placebo in 19 RCTs (1792 patients) was 0·72 (95% CI 0·62-0·83). The best evidence was for TCAs in seven trials (708 patients; RR 0·69, 0·54-0·87), but there was also a benefit of selective serotonin reuptake inhibitors in seven RCTs (324 patients; RR 0·74, 0·56-0·99), and serotonin and norepinephrine reuptake inhibitors in two trials (94 patients; RR 0·22, 0·08-0·59). Adverse events were not significantly more common with gut-brain neuromodulators, although rates of withdrawal due to adverse events were significantly higher. The certainty in the evidence for tricyclic antidepressants for global IBS symptoms was moderate, but it was low to very low for all other endpoints and drug classes studied.

INTERPRETATION

Some gut-brain neuromodulators are efficacious in reducing global symptoms and abdominal pain in IBS. The findings support guidelines that recommend use of tricyclic antidepressants for ongoing global symptoms or abdominal pain but also highlight a potential for SSRIs to be modestly effective for abdominal pain. More data for SNRIs, azapirones, and tetracyclic antidepressants in IBS are required.

FUNDING

None.

Pharmacotherapy for gastric and intestinal cramping pain: ‎ current and emerging therapies

INTRODUCTION

Acute gastrointestinal cramping pain (GICP) is a debilitating condition that affects many people worldwide, significantly reducing their quality of life. As such, prompt treatment is crucial.

AREAS COVERED

This article will explore relevant literature from databases such as PubMed, Scopus, Google Scholar, Cochrane Library, and Web of Science. Additionally, we searched ClinicalTrials.gov and the WHO ICTRP database for the latest clinical trials.

EXPERT OPINION

Consensus dictates that antispasmodics such as hyoscine-N-butyl bromide and mebeverine should be the primary treatment for GICP. If these prove ineffective, patients can switch to an antispasmodic with a different mode of action or add acetaminophen/NSAIDs for more severe cases. Currently, several antispasmodics are undergoing clinical trials, including drotaverine, alverine, pinaverium, otilonium bromide, fenoverine, tiropramide, otilonium bromide, trimebutine, and peppermint oil. Well-designed head-to-head studies are necessary to evaluate current antispasmodics' safety, efficacy, pharmacokinetic, and pharmacoeconomics profiles. Recent studies have shown that fixed-dose combinations of antispasmodics + NSAIDs or two different antispasmodics can improve patient compliance and synergistically reduce GICP. Therefore, it is recommended that the global availability and accessibility of these products be enhanced.

Tandospirone prevents stress-induced anxiety-like behavior and visceral hypersensitivity by suppressing theta oscillation enhancement via 5-HT1A receptors in the anterior cingulate cortex in rats

Tandospirone, a third-generation of antianxiety agent with fewer side effects, has been widely used in the treatment of anxiety. Moreover, it is interesting that tandospirone has been found to relieve gastrointestinal symptoms in patients with refractory irritable bowel syndrome who also have psychological dysfunctions. However, the underlying mechanism remains unclear. In this study, using a visceral hypersensitivity rat model induced by chronic water avoidance stress to mimic the symptoms of irritable bowel syndrome, we found that tandospirone relieved anxiety-like behavior and visceral hypersensitivity induced by stress. Meanwhile, stressed rats had increased 5-HT concentration, less 5-HT_1A receptor expression, and enhanced theta oscillations in the anterior cingulate cortex (ACC). Furthermore, the power of the theta band in ACC is positively correlated with the level of visceral sensitivity. Activation of 5-HT_1A receptors by its agonist, 8-OH-DPAT, to compensate for their effect in ACC reduced the enhancement of theta oscillations in ACC slices in stressed rats, whereas 5-HT_1A receptor antagonist, WAY100135, facilitates theta oscillations in slices of normal rats. Tandospirone reduced the enhancement of theta band power in ACC in vitro and in vivo, thus alleviating anxiety-like behavior and visceral hypersensitivity through 5-HT_1A receptors in stressed rats. These results suggest a novel mechanism by which tandospirone activates 5-HT_1A receptors to relieve stress-induced anxiety and visceral hypersensitivity by suppressing theta oscillation enhancement in ACC.

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.

Up-regulation of HTR1A reverses stress-induced visceral hypersensitivity through modulating interactions among the anterior cingulate cortex, insular cortex and hippocampus

Background: This study aimed to explore the effect of 5-HT1A receptors (HTR1A) on activation of the anterior cingulate cortex and simultaneous regulation of neural activity in the insular cortex and hippocampus.

Methods: The IBS rat model was established via chronic water avoidance stress (WAS). Visceral sensitivity was measured by electromyogram, and anxiety-like behaviours were evaluated by the open field test. HTR1A-specific lentivirus expressing green fluorescent protein was used to overexpress or down-regulate HTR1A expression. Protein expression levels were detected by western blot.

Results: Up-regulation of HTR1A in ACC could inhibit ACC sensitization and reverse the visceral hypersensitivity and anxiety-like behaviours induced by chronic psychological stress. In contrast, down-regulation of HTR1A in ACC might promote these behaviors in IBS rats. Additionally, up-regulation of HTR1A in ACC could inhibit IC and hippocampus sensitization, while down-regulation might have the opposite effect.

Conclusions: In IBS rats, HTR1A could modulate ACC activation and interactions among the ACC, IC and hippocampus. These effects might in turn contribute to the development of visceral hypersensitivity and anxiety-like behaviours induced by chronic psychological stress.

Comparison of the Efficacy of Buspirone and Placebo in Childhood Functional Abdominal Pain: A Randomized Clinical Trial

INTRODUCTION

Pharmacological interventions have not been successful in the treatment of childhood functional abdominal pain (FAP) hitherto. Buspirone is suggested to be efficacious in some of the abdominal pain-related functional gastrointestinal disorders based on evidences from the studies on adults. We aim to investigate the efficacy of buspirone on childhood FAP.

METHODS

This randomized clinical trial was conducted on 117 patients with childhood FAP aged 6-18 years. We randomly assigned patients to receive buspirone or placebo for 4 weeks, with the adjusted dosage for age. Participants completed the questionnaires assessing pain, depression, anxiety, somatization, and sleep disturbances at baseline, at the end of the 4-week therapy (first follow-up), and at 8 weeks after medication discontinuation (second follow-up). The primary outcome was treatment response rate, defined as reduced pain score of ≥2 or reporting no pain at the follow-up assessments.

RESULTS

Ninety-five patients completed the 4-week therapy (48 and 47 in buspirone and placebo groups, respectively). Both buspirone and placebo reduced pain after 4 weeks of treatment, and these effects were persistent 8 weeks after medication discontinuation (P < 0.001 for both groups at weeks 4 and 12). Treatment response rates for buspirone and placebo were 58.3% and 59.6% at week 4 (P = 0.902) and 68.1% and 71.1% at week 12 (P = 0.753), respectively.

DISCUSSION

Buspirone effectively improves pain and associated psychological symptoms including depressive symptoms, anxiety, somatization, and sleep disturbances in childhood FAP but has no superiority over placebo. Further studies, with the higher doses of buspirone and longer follow-ups are recommended.

Down-regulation of HTR1A-modulated ACC activation contributes to stress-induced visceral hyperalgesia in rats

BACKGROUND

Long-term stress was suggested to cause visceral hypersensitivity and promote functional gastrointestinal disorders (FGIDs). Some brain regions such as the anterior cingulate cortex (ACC) may play an important role for generating visceral hypersensitivity; however, its molecular mechanisms are not clear. This study aimed to explore the role of 5-HT1A receptors (HTR1As) in activating ACC and corresponding mechanism, in stress-induced visceral hyperalgesia rats.

METHODS

The VH rat model was established by chronic water avoidance stress (WAS), and the visceral sensitivity was measured by electromyogram. Rat's anxiety-like behaviors were evaluated by the open field test (OFT) and elevated plus maze (EPM). To overexpress or down-regulate HTR1A expression, HTR1A-specific lentivirus expressing the green fluorescent protein was administered into the ACC. Protein expression levels were observed by Western blot.

RESULTS

The protein expression of HTR1A in bilateral ACC in WAS group was significantly lower than that in normal control (NC) and Sham-WAS groups, while the levels of c-fos in the ACC of WAS rats were significantly higher. Down-regulation of HTR1As could induce VH in control rats with the increased expression of c-fos, p-ERK, and p-Akt in ACC, while up-regulation of HTR1As in the ACC could partly inhibit ACC sensitization and stress-induced visceral hyperalgesia.

CONCLUSIONS & INFERENCES

Down-regulation of HTR1As modulates ACC activation probably through activating ERK and Akt pathways, thus contributes to the formation of stress-induced visceral hyperalgesia.

Psychotropics, Antidepressants, and Visceral Analgesics in Functional Gastrointestinal Disorders

Purpose of Review

The functional gastrointestinal disorders, or disorders of gut-brain interaction as defined by the Rome IV criteria, are the most common diagnostic entities in gastroenterology. Treatments that address the dysregulation of gut-brain interaction with these disorders are increasingly gaining interest as a better option than for example traditional analgesics, particularly opioids. Antidepressants, antianxiety and antipsychotic medications, and visceral analgesics, now termed neuromodulators, are included in this update addressing the evidence of treatment benefit in disorders of brain-gut interaction.

Recent Findings

By a careful selection based on a multidimensional clinical profile, a decreased symptom burden, particularly regarding abdominal pain, nausea, and vomiting, as well as improved social function and quality of life, can be obtained by use of neuromodulators. There is good evidence for the peripheral neuromodulators from studies in bowel disorders, and the central neuromodulators both from indirect evidence in chronic pain disorders as well as selected disorders of brain-gut interaction.

Summary

Basic knowledge about the pharmacologic properties and clinical use of neuromodulators in disorders of brain-gut interaction improves the treatment outcome and avoids use of traditional analgesics.

Treatment of irritable bowel syndrome with neurotransmitter mediators

Irritable bowel syndrome (IBS), characterized by chronically recurring abdominal pain or discomfort and altered bowel habits and/or stool characters, is a chronic functional gastrointestinal disorder. Patients with IBS are more likely to suffer from coexistent mood disorder, depression, anxiety, and neuroticism. The mechanism of IBS may be related to such factors as abnormal intestinal motility, visceral hypersensitivity, disorder of brain-gut interactions, psychological disturbance and so on. General measures, such as antispasmodics, prokinetic agents, antidiarrheal agents, cathartic agent, and antidepressants are essential for effective IBS management. Anticholinergic agents and monoamine neurotransmitters, including their receptor agonists and antagonists, are all effective treatments for IBS; low-dose therapy can not only mitigate gastrointestinal motility, spasmolysis, and analgesia but also reduce psychological symptoms including anxiety and depression and improve the quality of life. Further larger-scale, long-term, randomized controlled clinical trials are warranted to confirm therapeutic effect and safety of neurotransmitter mediators for treatment of IBS.

Centrally Targeted Pharmacotherapy for Chronic Abdominal Pain: Understanding and Management

Chronic abdominal pain has a widespread impact on the individual and the society. Identifying and explaining mechanisms of importance for the pain experience within a biopsychosocial context are central in order to select treatment that has a chance for symptom reduction. With current knowledge of brain-gut interactions, chronic abdominal pain, which mostly appears in functional gastrointestinal disorders, to a large extent involves pain mechanisms residing within the brain. As such, the use of centrally targeted pharmacotherapy as an effective treatment option is obvious in a selected number of patients. The antidepressants are most common, but also other classes of medications can be used, either alone or in combination. The latter option refers to when there is insufficient effect of one drug alone or side effects limiting dosage, and when combined in lower doses, certain drugs give rise to augmentation effects. This chapter outlines basic mechanisms of importance for the understanding of chronic abdominal pain and the pharmacologic treatment options.

Empirically Supported Use of Psychiatric Medications in Adolescents and Adults with IBD

BACKGROUND

The use of psychotropic medications, particularly antidepressants, is common in patients with inflammatory bowel disease (IBD) in spite of a lack of their robust efficacy in this population. This review provides an overview of the use trends of different classes of antidepressant and anti-anxiety medication and their effects on mood, nervous system function, gastrointestinal physiology and immunity drawing from the literature available in the general population, other medical conditions, and when available, patients with IBD. It also covers the evidence base for the actions, efficacy, and potential complications of antidepressants organized by different classes.

METHODS

We conducted a PubMed search of articles relating the different drug classes probed to the terms above in different populations of interest. All types of articles were accepted including case reports and series, open and randomized trials, reviews, and expert opinion. We also examined the reference lists of the publications found.

RESULTS

Selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) are the most commonly prescribed agents for anxiety and depression in patients with IBD, though their efficacy for these conditions in the general population are mild to moderate at best. SSRIs are generally well tolerated, though at higher doses, they, like most antidepressant classes, can be associated with activation, serotonergic syndrome, and increased suicidal ideation. TCAs have many more serious side effects but have some shown efficacy for functional GI symptoms. A newer class, the serotonin noradrenergic reuptake inhibitors (SNRIs), can be effective for refractory depression, anxiety and chronic pain syndromes with a side effect profile similar to both SSRIs and more mild manifestations of TCAs. Mirtazapine has moderate efficacy for depression if sedation and weight gain side effects are tolerated and some small support for use in nausea and vomiting. Bupropion targets dopamine and noradrenaline reuptake and has moderate efficacy for depression, and some small support for use in fatigue and smoking cessation. Buspirone has an indication for generalized anxiety disorder though studies show only a minimal benefit. It has some growing evidence for use in functional dyspepsia. Most of these agents have physiological effects on the brain, immune system, and gastrointestinal tract (with the exception of bupropion) hence their therapeutic and side effects manifested in these systems.

CONCLUSION

Antidepressant medications are frequently prescribed for depression, anxiety disorders, and chronic pain syndromes, but overall support for their efficacy is modest at best. Psychological interventions have growing support for having much more robust effects without the side effects of antidepressants and should be considered first-line treatment or at least an adjunct to psychotropic medications for these conditions.

Inhibitory effect of TongXie-YaoFang formula on colonic contraction in rats

AIM: To investigate the pharmacological effect of TongXie-YaoFang (TXYF) formula and its underlying mechanisms.

METHODS: A neonatal maternal separation plus restraint stress (NMS + RS) model of diarrhea-predominant irritable bowel syndrome was developed by subjecting male Sprague-Dawley rats to daily maternal separation from postnatal days 2 to 21 plus restraint stress from days 50 to 59. Rats were randomly divided into two groups (NMS + RS and TXYF formula), and rats with no handling or separation were used as normal controls. Starting from postnatal day 60, rats were administered TXYF formula (9.84 g/100 g body weight) orally twice daily for 14 consecutive days, while the normal and NMS + RS groups were given distilled water. The distinctions of movement index (MI, area under the curve of contraction intensity/min, mg/min) and contraction frequency (CF, number of contractions/min, times/min) of isolated colonic longitudinal smooth muscle strips (CLSMs) in the three groups before and after treatment were observed with a Power Lab system. Different inhibitors were applied, and then 10^-4 mol/L acetylcholine chloride (Ach) was added to CLSMs to induce muscle contraction.

RESULTS: Before treatment, the MI of CLSMs in the NMS + RS and TXYF formula groups was similar and both higher than that in the normal group (545.49 ± 73.66 mg/min vs 245.76 ± 34.44 mg/min and 551.09 ± 54.29 mg/min vs 245.76 ± 34.44 mg/min, P < 0.01, respectively). After treatment, the MI in the TXYF formula group was lower than that in the NMS + RS group (261.39 ± 38.59 mg/min vs 533.9 ± 61.63 mg/min, P < 0.01). In the same way, the CF of CLSMs in the NMS + RS and TXYF formula groups was similar and both higher than that in the normal group (3.42 ± 0.25 times/min and 3.31 ± 0.21 vs 1.1 ± 0.17 times/min, P < 0.01) before treatment. After treatment, the CF in the TXYF formula group was lower than that in the NMS + RS group (1.42 ± 0.87 times/min vs 3.11 ± 0.82 times/min, P < 0.01) and similar to that in the normal group (1.42 ± 0.87 times/min vs 1.09 ± 0.13 times/min). When 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride and 4-aminopyridine were added to the bath and equilibrated for 30 min, respectively, and 10^-4 mol/L Ach was added to CLSMs to induce muscle contraction, MI of the CLSMs in the TXYF formula group was lower than that in the normal group (666 ± 36.32 mg/min vs 747.77 ± 49.47 mg/min, and 686.53 ± 39.17 mg/min vs 750.45 ± 29.39 mg/min; P < 0.01, respectively). The MI of CLSMs in the TXYF formula group was lower than that in the normal group after treatment with nifedipine (689.48 ± 30.84 mg/min vs 741.65 ± 32.41 mg/min; P < 0.05).

CONCLUSION: TXYF formula inhibits colon contraction in rats. This may be related to activation of specific potassium channels and inhibition of extracellular calcium internal flow.