Treatment of Irritable Bowel Syndrome (IBS)

Initial Management

• The American Gastroenterological Association recommends making a positive diagnosis for patients under 45 years meeting diagnostic criteria without alarming symptoms, avoiding extensive testing 1, 2, 3
• The British Society of Gastroenterology suggests listening to patient concerns, identifying beliefs, and considering using a symptom diary to track triggers 1, 2, 3
• The National Institute for Health and Care Excellence advises providing clear explanation about IBS as a disorder of gut-brain interaction with a benign but relapsing/remitting course 1, 2, 3
• The American College of Gastroenterology recommends a healthy lifestyle with regular exercise, which provides significant benefits for symptom management 4, 5

Dietary Interventions

• The National Institute for Health and Care Excellence recommends establishing patient's habitual fiber intake and modifying accordingly: increase for constipation, decrease for diarrhea 1, 2, 3
• The American Gastroenterological Association suggests identifying and reducing excessive intake of lactose, fructose, sorbitol, caffeine, or alcohol for diarrhea-predominant IBS (IBS-D) 4
• The British Society of Gastroenterology advises increasing soluble fiber (ispaghula/psyllium) starting with low doses (3-4g/day) and gradually increasing to avoid bloating for constipation-predominant IBS (IBS-C) 4, 5
• The American College of Gastroenterology recommends considering a trial of low FODMAP diet under supervision of a trained dietitian for persistent symptoms 4

Pharmacological Treatment by Predominant Symptom

For Abdominal Pain

• The American College of Gastroenterology recommends antispasmodics: anticholinergic agents like dicyclomine for pain relief 1, 2, 3
• The National Institute for Health and Care Excellence suggests peppermint oil may be useful as an antispasmodic, though evidence is limited 5

For Diarrhea-Predominant IBS (IBS-D)

• The American Gastroenterological Association recommends loperamide 4-12 mg daily either regularly or prophylactically to effectively slow intestinal transit and reduce stool frequency 1, 2, 3, 4
• The British Society of Gastroenterology advises codeine 30-60 mg, 1-3 times daily can be tried but central nervous system effects often limit use 1, 2, 3
• The National Institute for Health and Care Excellence suggests cholestyramine may benefit a small subset of patients with bile salt malabsorption but is often less well tolerated than loperamide 1, 2, 3, 4

For Constipation-Predominant IBS (IBS-C)

• The American College of Gastroenterology recommends increasing dietary fiber or using soluble fiber supplements like ispaghula/psyllium 1, 2, 3

For Bloating

• The National Institute for Health and Care Excellence advises trying reducing intake of fiber/lactose/fructose as relevant 1, 2, 3
• The American Gastroenterological Association recommends probiotics may improve global symptoms and bloating; recommend a 12-week trial and discontinue if no improvement 4, 5

Second-Line Treatments

• The American College of Gastroenterology recommends tricyclic antidepressants (TCAs) like amitriptyline/trimipramine are effective for pain and global symptoms, especially when insomnia is prominent, but may aggravate constipation 1, 2, 3, 4
• The National Institute for Health and Care Excellence advises starting TCAs at low doses (10 mg once daily) and increase slowly to maximum 30-50 mg once daily 5
• The British Society of Gastroenterology suggests selective serotonin reuptake inhibitors (SSRIs) may be considered if TCAs are not tolerated 4, 5

Psychological Therapies

• The American Gastroenterological Association recommends initially offering explanation, reassurance, and simple relaxation therapy 1, 2, 3
• The National Institute for Health and Care Excellence advises considering IBS-specific cognitive behavioral therapy or gut-directed hypnotherapy for symptoms refractory to pharmacological treatment for 12 months 4, 5
• The British Society of Gastroenterology suggests biofeedback may be especially helpful for disordered defecation 1, 2, 3

Treatment Monitoring

• The American College of Gastroenterology recommends reviewing treatment efficacy after 3 months and discontinue ineffective medications 4, 5
• The National Institute for Health and Care Excellence advises TCAs should be continued for at least 6 months if the patient reports symptomatic improvement 5
• The American Gastroenterological Association suggests recognizing that symptoms may relapse and remit over time, requiring periodic adjustment of treatment strategy 4

Important Considerations

• The American Gastroenterological Association recommends avoiding extensive testing once IBS diagnosis is established 4, 5

Management of Irritable Bowel Syndrome with Lifestyle and Pharmacological Interventions

First-Line Management: Lifestyle and Dietary Modifications

• For patients with moderate to severe gastrointestinal symptoms, the American Gastroenterological Association recommends a supervised trial of low FODMAP diet delivered in three phases: restriction, reintroduction, and personalization, as this approach is particularly effective but requires professional guidance to avoid nutritional deficits 6

Second-Line Treatment: Neuromodulators

• The European Society of Gastroenterology recommends prescribing tricyclic antidepressants (TCAs) starting with amitriptyline 10 mg once daily and titrating to 30-50 mg once daily for patients with mixed symptoms or refractory pain, as low-dose TCAs are preferred for gastrointestinal symptoms, particularly pain, and are the most effective first-line pharmacological treatment for mixed IBS 6
• The American College of Gastroenterology suggests that if there is a concurrent mood disorder, a selective serotonin reuptake inhibitor (SSRI) should be used instead of low-dose TCAs, because low-dose TCAs are unlikely to address psychological symptoms 6

Psychological Therapies for Refractory Cases

• The British Society of Gastroenterology recommends considering IBS-specific cognitive behavioral therapy or gut-directed hypnotherapy when symptoms persist despite pharmacological treatment for 12 months, as these brain-gut behavior therapies are specifically designed for IBS and differ from psychological therapies that target depression and anxiety alone 6

Multidisciplinary Care Coordination

• The World Gastroenterology Organisation suggests building collaborative links with gastroenterology dietitians and gastropsychologists to coordinate high-quality care, and referring patients to a dietitian if they report considerable intake of foods that trigger IBS symptoms, or have dietary deficits or nutrition red flags 6
• The American Gastroenterological Association recommends referring patients to a gastropsychologist if IBS symptoms or their impact are moderate to severe, and the patient accepts that symptoms are related to gut-brain dysregulation, and has time to devote to learning new coping strategies 6

Enhancing Patient Self-Management

• The European Society of Gastroenterology recommends promoting patient empowerment through education and psychoeducation using handouts, self-help books, websites, and apps, targeting physical activity, sleep hygiene, mindful eating, and assertive communication, as self-management techniques improve IBS symptoms and quality of life in the short term 6

Treatment for Irritable Bowel Syndrome (IBS)

Dietary Interventions

• The American Gastroenterological Association recommends starting with soluble fiber (ispaghula/psyllium) at 3-4 g/day and gradually increasing to avoid bloating, as this is effective for global symptoms and abdominal pain in patients with IBS 7
• Avoiding insoluble fiber (wheat bran) is recommended as it exacerbates symptoms, particularly bloating, in patients with IBS 7
• Food elimination diets based on IgG antibodies are not recommended for patients with IBS, according to the American Gastroenterological Association 7
• A gluten-free diet is not recommended in IBS, unless the patient has a confirmed diagnosis of celiac disease or non-celiac gluten sensitivity, as stated by the American Gastroenterological Association 7

Pharmacological Treatment

• Common side effects of antispasmodics with anticholinergic properties include dry mouth, visual disturbance, and dizziness, in patients with IBS 7
• Loperamide may be prescribed at a dose of 4-12 mg daily to reduce stool frequency, urgency, and fecal soiling in patients with diarrhea-predominant IBS (IBS-D), with careful titration to avoid abdominal pain, bloating, nausea, and constipation 7

Second-Line Treatment

• The American Gastroenterological Association recommends considering a supervised trial of low FODMAP diet for patients with persistent symptoms refractory to first-line measures, which requires supervision by a trained dietitian to avoid nutritional deficits and ensure proper reintroduction according to tolerance 7

Second-Line Pharmacological Treatment

• Tricyclic antidepressants (TCAs) are the most effective first-line pharmacological treatment for global symptoms, abdominal pain, and mixed IBS symptoms refractory to first-line measures, with a recommended starting dose of amitriptyline 10 mg once daily and titration to a maximum of 30-50 mg once daily, as stated by the American Gastroenterological Association 7
• TCAs should be continued for at least 6 months if the patient reports symptomatic improvement, and patients should be counseled about the rationale for their use and side-effect profile, according to the American Gastroenterological Association 7
• Selective serotonin reuptake inhibitors (SSRIs) may be effective for global symptoms and can be considered if TCAs are not tolerated or if there is concurrent mood disorder, with careful monitoring for anxiety and disturbed sleep, as recommended by the American Gastroenterological Association 7

Important Caveats

• The American Gastroenterological Association recommends avoiding colonoscopy in IBS except in those with alarm symptoms or signs, or those with IBS-D who have atypical features that increase likelihood of microscopic colitis, such as nocturnal or severe watery diarrhea, age ≥50 years, coexistent autoimmune disease, or weight loss 7
• In IBS-D with atypical features such as nocturnal diarrhea or prior cholecystectomy, the American Gastroenterological Association recommends considering testing for bile acid malabsorption 7