What are the treatment options for Irritable Bowel Syndrome (IBS) with constipation (IBS-C)?

Treatment Options for Irritable Bowel Syndrome with Constipation (IBS-C)

For IBS-C treatment, soluble fiber supplementation should be used as first-line therapy, followed by secretagogues like linaclotide or lubiprostone for patients with inadequate response. 1, 2

First-Line Treatments

Dietary Modifications

• Soluble fiber supplementation:

  • Start with 3-4g/day of ispaghula (psyllium) and gradually increase 1, 2
  • Strong recommendation based on systematic reviews showing benefit for IBS-C symptoms 1
  • Avoid insoluble fiber (wheat bran, whole grains) as it may worsen bloating and abdominal pain 1

• Low FODMAP Diet (LFD):

  • Consider for motivated patients willing to follow the 3-phase approach 1:
    1. Restriction phase (4-6 weeks maximum)
    2. Reintroduction phase
    3. Personalization phase
  • Implementation should be guided by a registered dietitian 2
  • While evidence is stronger for IBS-D, it may help reduce bloating in IBS-C 1

Second-Line Treatments

Pharmacological Options

• Secretagogues (for inadequate response to fiber):

  • Linaclotide: 290 μg once daily - FDA-approved for IBS-C in adults 2, 3

    • Guanylate cyclase-C agonist that increases intestinal fluid secretion
    • Moderate evidence for improvement in abdominal bloating 2

  • Lubiprostone: 8 μg twice daily - FDA-approved for IBS-C in women ≥18 years 2, 4

    • Take with food to reduce nausea 4
    • Contraindicated in patients with severe diarrhea or mechanical GI obstruction 4

• Polyethylene glycol (PEG):

  • Add if inadequate response to fiber and/or peppermint oil 2
  • Safe for long-term use

• Peppermint oil:

  • Can improve global symptoms and abdominal pain 2
  • Consider as adjunct therapy

Third-Line Treatments

For Persistent or Refractory Symptoms

• Antispasmodics:

  • For management of abdominal pain 2
  • Examples include dicyclomine

• Gut-brain neuromodulators:

  • Tricyclic antidepressants (TCAs) like amitriptyline
  • Start at low doses and continue for at least 6 months in responders 2
  • Note: SSRIs are not recommended based on AGA guidelines 2

• Psychological therapies (for severe or refractory symptoms):

  • Cognitive Behavioral Therapy (CBT): 4-12 sessions 2
  • Gut-directed hypnotherapy 2
  • Mindfulness-based stress reduction 2

Treatment Algorithm

1. Start with dietary modifications:

   • Soluble fiber supplementation (ispaghula/psyllium)
   • Consider low FODMAP diet with dietitian guidance

2. If inadequate response after 4 weeks, add:

   • Peppermint oil and/or polyethylene glycol

3. If still inadequate response after 4 weeks, add a secretagogue:

   • Linaclotide (preferred based on efficacy) or
   • Lubiprostone (for women ≥18 years)

4. For persistent symptoms, consider:

   • Antispasmodics or gut-brain neuromodulators (TCAs)

5. For severe or refractory symptoms:

   • Psychological therapies
   • Multidisciplinary approach

Monitoring and Follow-up

• Use a symptom diary to identify triggers and monitor treatment response 2
• Assess treatment response after 4+ weeks for first-line treatments 2
• Review efficacy after 3 months and discontinue if no response 2

Important Considerations

• Avoid insoluble fiber as it may worsen symptoms in IBS-C patients 1
• Secretagogues have the strongest evidence for efficacy in IBS-C but should be reserved for patients who fail first-line therapy 2, 3, 4
• Lubiprostone is only approved for women with IBS-C, while linaclotide is approved for all adults 3, 4
• Syncope and hypotension have been reported with lubiprostone, particularly at higher doses 4