What are the treatment options for Irritable Bowel Syndrome (IBS)?

Treatment Options for Irritable Bowel Syndrome (IBS)

The treatment of IBS should follow a symptom-based approach, starting with lifestyle and dietary modifications, followed by targeted pharmacological interventions based on predominant symptoms (constipation, diarrhea, or pain). 1

Diagnostic Approach

• Positive diagnosis can be made in patients <45 years meeting three or more Rome criteria without alarm symptoms, without extensive testing 2
• Limited investigations are appropriate; avoid excessive testing 1

First-Line Treatments

Lifestyle and Dietary Modifications

• Healthy lifestyle recommendations:
  • Regular exercise (improves overall symptoms despite weak evidence) 1
  • Balanced diet with adequate fiber intake 2
  • Establish regular time for defecation 2

Dietary Interventions

• For IBS with constipation (IBS-C):

  • Increase soluble fiber (ispaghula/psyllium) starting at 3-4g/day with gradual increase 1
  • Avoid insoluble fiber (wheat bran) as it may worsen symptoms 1

• For IBS with diarrhea (IBS-D):

  • Decrease fiber intake 2
  • Identify and reduce excessive lactose, fructose, sorbitol, caffeine, or alcohol 2
  • Trial of lactose/fructose/alcohol exclusion if appropriate 2

• For all IBS subtypes:

  • Consider low FODMAP diet under dietitian supervision (particularly effective for bloating and gas) 1
  • Trial of probiotics for up to 12 weeks (discontinue if no improvement) 1

Pharmacological Approach Based on Predominant Symptoms

For Abdominal Pain

1. Antispasmodics: Anticholinergic agents like dicyclomine 2
2. Peppermint oil: Effective for pain relief and ranked highly for global symptom improvement 1
3. Tricyclic antidepressants (TCAs): Particularly effective for right-sided intestinal pain
   • Start with amitriptyline 10mg at bedtime, gradually increase if needed 1
   • Caution: may worsen constipation 2

For IBS with Constipation (IBS-C)

1. Polyethylene glycol (PEG): First-line therapy for constipation symptoms 1
2. Lubiprostone: 8 mcg twice daily for women ≥18 years old 3
   • Adjust dose for hepatic impairment 3
   • Common side effects: nausea (29%), diarrhea (12%), headache (11%) 3
3. Linaclotide: 72-290mcg daily for inadequate response to other treatments 1

For IBS with Diarrhea (IBS-D)

1. Loperamide: 4-12 mg daily either regularly or prophylactically 2
2. Cholestyramine: May benefit a small number but often less well tolerated than loperamide 2
3. 5-HT3 receptor antagonists: (e.g., ondansetron) highly effective for IBS-D 1

Psychological Interventions

• For patients with severe symptoms or when physical treatments fail:
  • Cognitive behavioral therapy (CBT) 1
  • Gut-directed hypnotherapy 1
  • Mindfulness-based stress reduction 1
  • Simple relaxation therapy using audiotapes 2

Treatment Algorithm

1. Initial approach (4-6 week trial):

   • Lifestyle modifications + dietary changes
   • Symptom-specific medication:
     • Pain: antispasmodics or peppermint oil
     • Constipation: PEG or soluble fiber
     • Diarrhea: loperamide

2. If inadequate response after 4-6 weeks:

   • Add TCA (amitriptyline 10mg at bedtime)
   • For IBS-C: consider lubiprostone or linaclotide
   • For IBS-D: consider 5-HT3 antagonists or rifaximin

3. If still inadequate response after 12 weeks:

   • Consider psychological interventions
   • Refer to gastroenterology specialist

Important Cautions

• Avoid ineffective treatments:

  • Conventional analgesics and opioids (may worsen constipation) 1
  • Continuing ineffective treatments beyond 12 weeks 1
  • Starting TCAs at too high a dose 1

• Medication side effects to monitor:

  • Lubiprostone: nausea (take with food), diarrhea, syncope and hypotension 3
  • TCAs: constipation, dry mouth, drowsiness 2

• Discontinue treatments that don't show benefit after an appropriate trial period 1

By following this structured approach to IBS management, focusing on the predominant symptoms and adjusting therapy based on response, patients can achieve significant improvement in quality of life and reduction in morbidity.