What are the treatment options for irritable bowel syndrome (IBS)?

Treatment of Irritable Bowel Syndrome (IBS)

The treatment of irritable bowel syndrome should follow a stepwise approach that begins with lifestyle and dietary modifications, followed by symptom-specific pharmacological interventions, and psychological therapies for refractory cases. 1, 2

Initial Management

• Make a positive diagnosis for patients <45 years meeting diagnostic criteria without alarming symptoms, avoiding extensive testing 3
• Listen to patient concerns, identify beliefs, and consider using a symptom diary to track triggers 3
• Provide clear explanation about IBS as a disorder of gut-brain interaction with a benign but relapsing/remitting course 3
• Recommend healthy lifestyle with regular exercise, which provides significant benefits for symptom management 1, 2

Dietary Interventions

• Establish patient's habitual fiber intake and modify accordingly: increase for constipation, decrease for diarrhea 3
• For diarrhea-predominant IBS (IBS-D): identify and reduce excessive intake of lactose, fructose, sorbitol, caffeine, or alcohol 1
• For constipation-predominant IBS (IBS-C): increase soluble fiber (ispaghula/psyllium) starting with low doses (3-4g/day) and gradually increasing to avoid bloating 1, 4
• Consider a trial of low FODMAP diet under supervision of a trained dietitian for persistent symptoms 1, 5
• Avoid recommending insoluble fiber (wheat bran) as it may worsen symptoms 2, 4

Pharmacological Treatment by Predominant Symptom

For Abdominal Pain

• Antispasmodics: anticholinergic agents like dicyclomine for pain relief 3
• Peppermint oil may be useful as an antispasmodic, though evidence is limited 2, 4

For Diarrhea-Predominant IBS (IBS-D)

• Loperamide 4-12 mg daily either regularly or prophylactically effectively slows intestinal transit and reduces stool frequency 3, 1
• Codeine 30-60 mg, 1-3 times daily can be tried but central nervous system effects often limit use 3
• Cholestyramine may benefit a small subset of patients with bile salt malabsorption but is often less well tolerated than loperamide 3, 1

For Constipation-Predominant IBS (IBS-C)

• Increase dietary fiber or use soluble fiber supplements like ispaghula/psyllium 3
• Lubiprostone is indicated for IBS-C in women at least 18 years old at a dose of 8 mcg twice daily 6
• Osmotic laxatives like polyethylene glycol may increase bowel frequency but overall efficacy against IBS symptoms is unclear 4

For Bloating

• Try reducing intake of fiber/lactose/fructose as relevant 3
• Probiotics may improve global symptoms and bloating; recommend a 12-week trial and discontinue if no improvement 1, 2

Second-Line Treatments

• Tricyclic antidepressants (TCAs) like amitriptyline/trimipramine are effective for pain and global symptoms, especially when insomnia is prominent, but may aggravate constipation 3, 1
• Start TCAs at low doses (10 mg once daily) and increase slowly to maximum 30-50 mg once daily 2
• Selective serotonin reuptake inhibitors (SSRIs) may be considered if TCAs are not tolerated 1, 2

Psychological Therapies

• Initially offer explanation, reassurance, and simple relaxation therapy 3
• Consider IBS-specific cognitive behavioral therapy or gut-directed hypnotherapy for symptoms refractory to pharmacological treatment for 12 months 1, 2
• Biofeedback may be especially helpful for disordered defecation 3
• Refer to psychiatric services for serious psychiatric disease 3

Treatment Monitoring

• Review treatment efficacy after 3 months and discontinue ineffective medications 1, 2
• TCAs should be continued for at least 6 months if the patient reports symptomatic improvement 2
• Recognize that symptoms may relapse and remit over time, requiring periodic adjustment of treatment strategy 1

Important Considerations

• Personalized dietary therapy under supervision of a qualified health practitioner can significantly improve symptoms and quality of life 7
• A multipronged approach considering the nature of symptoms (diarrhea-predominant or constipation-predominant) should guide pharmacological treatment choices 8
• Avoid extensive testing once IBS diagnosis is established 1, 2
• Monitor for side effects of medications, particularly nausea and diarrhea with lubiprostone 6