What is the treatment for Irritable Bowel Syndrome with Diarrhea (IBS-D)?

Treatment of Irritable Bowel Syndrome with Diarrhea (IBS-D)

For IBS-D treatment, start with lifestyle modifications and dietary changes, then progress to antispasmodics or peppermint oil for pain and loperamide for diarrhea, followed by tricyclic antidepressants if symptoms persist, and consider 5-HT3 antagonists, rifaximin, or eluxadoline for refractory cases. 1

First-Line Approaches

Dietary and Lifestyle Modifications

• Regular exercise should be recommended to all IBS patients as it can provide benefits, particularly for constipation 2, 1
• Dietary modifications:
  • Decrease fiber intake for IBS-D patients 1
  • Identify and reduce excessive lactose, fructose, sorbitol, caffeine, and alcohol 1
  • Consider a trial of low FODMAP diet under dietitian supervision to reduce bloating and pain 1
  • Establish a regular time for defecation 1

First-Line Pharmacological Treatments

• Antidiarrheals: Loperamide 4-12 mg daily to control diarrhea symptoms 1
  • Effective for stool frequency but limited effect on abdominal pain
  • Better tolerated than cholestyramine
• Antispasmodics (e.g., dicyclomine) or peppermint oil for abdominal pain 1
  • Peppermint oil ranks highly for global symptom improvement

Second-Line Approaches (if inadequate response after 4-6 weeks)

Pharmacological Options

• Tricyclic antidepressants (TCAs): Start with amitriptyline 10 mg at bedtime, gradually increase if needed 1

  • Most effective for right-sided intestinal pain
  • Caution: May cause side effects including constipation, dry mouth, and drowsiness
  • Avoid in patients with severe constipation

• 5-HT3 receptor antagonists (e.g., ondansetron): Highly effective for IBS-D 1

  • Start at 4 mg once daily and titrate up to 8 mg three times daily
  • Main side effect is constipation

• Rifaximin (non-absorbable antibiotic): Effective for global symptoms in IBS-D 1, 3

  • FDA-approved for IBS-D
  • Limited effect on abdominal pain specifically
  • Has the most favorable safety profile among FDA-approved agents 3

• Eluxadoline (mixed mu-opioid receptor agonist): FDA-approved for IBS-D 4, 5

  • Dosage: 100 mg twice daily with food
  • Reduced dose (75 mg twice daily) for patients:
    • Unable to tolerate 100 mg dose
    • Receiving concomitant OATP1B1 inhibitors
    • With mild/moderate hepatic impairment
    • With moderate/severe renal impairment
  • Contraindicated in patients:
    • Without a gallbladder (increased risk of pancreatitis)
    • With biliary duct obstruction or sphincter of Oddi disease
    • With alcoholism or who drink >3 alcoholic beverages daily
    • With history of pancreatitis
    • With severe hepatic impairment
    • With history of chronic/severe constipation

• Bile acid sequestrants (e.g., cholestyramine): Consider in patients with suspected bile acid diarrhea 2, 1

  • Consider 23-seleno-25-homotaurocholic acid scanning or serum 7α-hydroxy-4-cholesten-3-one to exclude bile acid diarrhea in patients with atypical features like nocturnal diarrhea or prior cholecystectomy

Third-Line Approaches (for persistent symptoms)

Psychological Interventions

• Cognitive behavioral therapy (CBT), gut-directed hypnotherapy, or mindfulness-based stress reduction 2, 1
  • Recommended for patients with severe symptoms that impair quality of life
  • Consider when physical treatments fail

Important Caveats and Pitfalls

1. Avoid excessive investigation in typical IBS patients 1

   • Colonoscopy only indicated with alarm symptoms/signs or atypical features suggesting microscopic colitis

2. Avoid ineffective treatments:

   • Conventional analgesics or opioids are ineffective and may worsen symptoms 1
   • Discontinue ineffective treatments after 12 weeks 1

3. Monitor for complications:

   • Discontinue eluxadoline if severe constipation develops 4
   • Be aware of the risk of pancreatitis with eluxadoline, especially in patients without a gallbladder 4

4. Consider psychological factors that may contribute to symptom severity 1

5. Explain the condition to patients as a disorder of gut-brain interaction, including how it's impacted by diet, stress, and emotional responses to symptoms 2

By following this structured approach to IBS-D management, clinicians can effectively address both diarrhea and abdominal pain symptoms while minimizing risks and improving quality of life for patients.