What are the management options for Irritable Bowel Syndrome with Constipation (IBS-C)?

Management of Irritable Bowel Syndrome with Constipation (IBS-C)

Linaclotide, a guanylate cyclase-C agonist, is the most efficacious second-line drug for IBS-C in secondary care, although diarrhea is a common side effect. 1

First-Line Management Options

Dietary and Lifestyle Modifications

• Low-FODMAP diet: 50-60% of patients experience significant symptom improvement; should be implemented under supervision of a trained gastroenterology dietitian 2
• Fiber supplementation:
  • Soluble fiber (e.g., psyllium) may be beneficial for IBS-C symptoms 3
  • Start with low dose and increase slowly to minimize adverse effects like bloating 3
  • Insoluble fiber has less evidence of benefit and may worsen symptoms in some patients 4
• Regular exercise: Recommended as a first-line treatment despite limited evidence 2
• Establish regular defecation schedule 2

Over-the-Counter Options

• Polyethylene glycol: May be effective for constipation in IBS, though abdominal pain is a common side effect 1
• Peppermint oil: May be effective for global symptoms and abdominal pain; gastroesophageal reflux is a common side effect 1

Second-Line Pharmacological Options

Secretagogues (strongest evidence)

1. Linaclotide:

   • FDA-approved for IBS-C in adults 5
   • Strong recommendation, high-quality evidence 1
   • Likely the most efficacious secretagogue for IBS-C 1
   • Common side effect: diarrhea

2. Lubiprostone:

   • FDA-approved for IBS-C in women ≥18 years old 6
   • Strong recommendation, moderate-quality evidence 1
   • Less likely to cause diarrhea than other secretagogues 1
   • Common side effect: nausea 1

3. Tenapanor:

   • Strong recommendation, high-quality evidence 1
   • Sodium-hydrogen exchange inhibitor 1
   • Common side effect: diarrhea 1
   • May not be available in many countries 1

4. Plecanatide:

   • Guanylate cyclase-C agonist (similar to linaclotide) 1
   • Weak recommendation, very low-quality evidence 1
   • Common side effect: diarrhea 1

Antispasmodics

• May be effective for global symptoms and abdominal pain 1
• Weak recommendation, very low-quality evidence 1
• Common side effects: dry mouth, visual disturbance, dizziness 1

Gut-Brain Neuromodulators

• Tricyclic antidepressants: Effective for IBS pain but should be avoided if constipation is a major feature 2
• Consider when symptoms have not improved after 12 months of drug treatment 1

Psychological Therapies

• IBS-specific cognitive behavioral therapy: Strong recommendation for global symptoms, low-quality evidence 1
• Gut-directed hypnotherapy: Strong recommendation for global symptoms, low-quality evidence 1
• Consider when symptoms have not improved after 12 months of drug treatment 1

Management of Severe or Refractory IBS-C

1. Review diagnosis and consider further targeted investigation 1
2. Implement integrated multidisciplinary approach 1
3. Consider combination gut-brain neuromodulators (augmentation) for severe symptoms, with vigilance for risks of serotonin syndrome 1
4. Avoid iatrogenic harms from opioid prescribing, unnecessary surgery, and unproven therapeutic approaches 1

Treatment Algorithm

1. Start with dietary modifications (low-FODMAP diet) and lifestyle changes (exercise, regular defecation schedule)
2. Add soluble fiber and/or peppermint oil
3. If inadequate response, add polyethylene glycol
4. If still inadequate response, add a secretagogue (linaclotide preferred based on efficacy)
5. For persistent symptoms, consider adding an antispasmodic or gut-brain neuromodulator
6. For severe or refractory symptoms, consider psychological therapies and multidisciplinary approach

Important Considerations

• Medication side effects may transform IBS subtype (e.g., constipation-predominant to diarrhea-predominant) 2
• Engage in shared decision-making with patients when choosing therapy 1
• Consider cost and insurance coverage when selecting medications, as newer agents may have limited coverage 1