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Irritable Bowel Syndrome? Clinical Trials Offer Hope

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Irritable bowel syndrome

Irritable Bowel Syndrome (IBS) is characterized by abnormal stooling frequency and consistency along with abdominal pain in the absence of any medical or surgical problem in the gut. About 15% of the population is affected by this problem at some point of time in their life but only 10% of these get a physician consultation. Women are 2-3 times more affected than men. Some coexisting conditions with IBS are chronic fatigue syndrome, painful menstrual bleeding, fibromyalgia, and non-ulcer dyspepsia.

Causes of IBS

The exact cause of this condition is unknown but some factors that have been implicated are biopsychosocial factors, alteration in normal gut flora, and changes in diet. About half of the patients referred to a gastroenterology clinic also have psychiatric illnesses such as anxiety, depression, and neurosis. Some patients cannot tolerate short-chain carbohydrates (fructose, lactose, and sorbitol) collectively called as FODMAPs (fermentable, oligo, di and monosaccharides and polyols). The fermentation of these kinds of foods leads to abdominal bloating, pain, and altered bowel habits.

Clinical Features of Irritable Bowel Syndrome

Most patients report recurrent abdominal discomfort that is relieved after passing stool. Due to the accumulation of excessive gases in the gut, abdominal bloating worsens throughout the day. Some patients are frequently constipated while others report frequent diarrhea. Based on that, IBS is classified into two types: constipation-predominant IBS and diarrhea-predominant IBS. Most patients report the passage of mucus in stool but blood in stool is not seen. On physical examination, there is no significant finding except for mild tenderness of the lower abdomen.

Diagnosing IBS

The diagnosis of IBS is made after ruling out all pathological conditions that mimic the symptoms of IBS.  Complete blood count, fecal calprotectin, and sigmoidoscopy are commonly done and are normal in IBS. If a patient is older than 40 years of age, then a colonoscopy is done to rule out colorectal cancer. Some medical conditions that should be ruled out in patients with diarrhea-predominant IBS include celiac disease, microscopic colitis, lactose intolerance, and parasitic infection (if a patient has recently traveled to developing countries). Clinicians also use ROME III criteria for the diagnosis of IBS.

ROME III Criteria for Clinical Diagnosis of IBS

Recurrent abdominal discomfort on at least 3 days per month in the last 3 months, associated with 2 or more of the following:
  • Onset associated with a change in frequency of stool
  • Onset associated with a change in form (consistency) of stool
  • Improvement with defecation
 

Management of Irritable Bowel Syndrome

It is important to reassure people who display IBS symptoms, as many are worried that they might have cancer. The patient should be reassured that this condition is not due to any pathological disease but instead is due to some behavioral and psychosocial factors.

Some of the dietary measures that may help include a low FODMAPs diet, a low gluten diet, elimination of lactose from the daily diet, and reducing intake of caffeine, alcohol, and artificial sweeteners, such as sorbitol. Drinking plenty of water to maintain optimum hydration and taking time while eating food is also important.

Probiotic capsules are also effective if taken for several months. Patients who do not respond to the above measures may be prescribed drugs such as amitriptyline or imipramine. For constipation-predominant IBS, 5-HT4 agonist prucalopride, chloride channel activators (Lubiprostone), and the guanylate cyclase-C receptor agonist (linaclotide) have shown to be effective. For intractable cases, psychological interventions should be tried. In patients with difficult-to-treat symptoms, trials of anti-inflammatory agents, such as ketotifen or mesalazine and the antibiotic rifaximin can be considered.

Recent IBS Advances and Clinical Trials

  • Olorinab: Olorinab is a potent and selective agonist of the cannabinoid receptor. A phase Ib study is underway to assess the effect of oral Olorinab on gastrointestinal transit in patients with constipation-predominant IBS.
  • A study to evaluate the relationship between the bile acids, short-chain fatty acids, and bacteria inside the gut is currently underway. The target study population is patients with IBS (both diarrhea-predominant and constipation-predominant) and healthy controls.
  • A low FODMAP diet for 4 weeks: This study is being done to know if a low FODMAP diet causes an alteration in the gut lining which mediates improvement in clinical features of IBS.
  • Low FODMAP plus PEG 3350: A clinical trial is being conducted to assess the efficacy of PEG 3350 plus low FODMAP diet vs PEG 3350 plus sham diet in constipation-predominant IBS. This study is in the early phase 1 stage.
  • Hydrogen breath test as an instrument to predict Rifaximin-response in diarrhea-predominant IBS: The objective of this study is to determine whether hydrogen breath testing can be used to identify patients with diarrhea-predominant IBS who are more likely to show response to rifaximin.
  • Curcumin food supplement: This study aims to evaluate the effect of a curcumin food supplement on the gut microbiota of children with IBS.
  • Combined Rifaximin plus N-acetylcysteine (NAC): The objective of this study is to determine the efficacy of combined Rifaximin plus NAC vs. Rifaximin in decreasing clinical symptoms in patients with diarrhea-predominant IBS.
  • Yogic breathing: A clinical trial is undergoing to assess the effect of yogic breathing in improving the symptoms of IBS.
  • BMS-562086: A study to evaluate the effectiveness of BMS-562086 in patients with diarrhea-predominant IBS is being conducted currently and its clinical trial is in phase 2.
 
References
  1. Barbara G et al: The immune system in irritable bowel syndrome.
    J Neurogastroenterol Motil 17:349, 2011
  2. Drossman DA: Functional gastrointestinal disorders: History, pathophysiology, clinical features, and Rome IV. Gastroenterology 150:1262,
    2016.
  3. Eswaran SL et al: A randomized controlled trial comparing the low 2283
    FODMAP diet vs. modified NICE guidelines in US adults with IBS-D.
    Am J Gastroenterol 111:1824, 2016

     

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This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. CenTrial Data Ltd. does not take responsibility for possible health consequences of any person or persons reading or following the information in this educational content. Treatments and clinical trials mentioned may not be appropriate or available for all trial participants. Outcomes from treatments and clinical trials may vary from person to person. Consult with your doctor as to whether a clinical trial is a suitable option for your condition.