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

Treatment Guidelines for Irritable Bowel Syndrome (IBS)

The management of IBS should follow a stepwise approach beginning with lifestyle modifications and dietary changes, progressing to targeted pharmacological interventions based on predominant symptoms, and incorporating psychological therapies for refractory cases. 1

Diagnosis and Initial Approach

• Confidently diagnose IBS in patients under 45 years meeting Rome criteria without alarm symptoms
• Provide patient education on the benign but chronic nature of IBS, emphasizing brain-gut interaction
• Consider using a symptom diary to help patients identify triggers and patterns

First-Line Interventions

Dietary and Lifestyle Modifications

• Implement balanced diet with appropriate fiber adjustments:
  • Increase soluble fiber (ispaghula/psyllium) for IBS-C
  • Reduce insoluble fiber for IBS-D
  • Ensure adequate hydration
• Identify and eliminate food triggers (lactose, fructose, caffeine, alcohol)
• Consider a low-FODMAP diet under dietitian supervision (50-60% of patients experience significant improvement) 1
• Encourage regular physical activity and stress reduction techniques

First-Line Pharmacological Treatment

• For IBS with abdominal pain: Antispasmodics (anticholinergic agents like dicyclomine) 1
• For IBS-D: Loperamide 4-12 mg daily 1
• For IBS-C: Soluble fiber supplements or osmotic laxatives like polyethylene glycol 1
• For general symptoms: Consider peppermint oil (caution with GERD) 1

Second-Line Interventions

For Persistent Symptoms

• For IBS-C:

  • Linaclotide 290 mcg once daily (take on empty stomach, 30 minutes before first meal) 2
  • Other secretagogues: lubiprostone (FDA-approved for women ≥18 years) or plecanatide 1

• For IBS-D:

  • Cholestyramine (for bile acid malabsorption) 1
  • Consider 5-HT3 receptor antagonists (alosetron) with caution due to risk of ischemic colitis 3, 4

• For persistent pain:

  • Tricyclic antidepressants (TCAs) starting at low doses (10 mg at night), titrating slowly by 10 mg/week 3
  • Continue for at least 6 months if symptomatic response occurs 3
  • SSRIs can be considered as alternatives 3

Third-Line Interventions

For Refractory Symptoms

• Psychological therapies:

  • Cognitive behavioral therapy (CBT)
  • Gut-directed hypnotherapy
  • Biofeedback
  • Relaxation therapy 1

• Other pharmacological options:

  • For severe, persistent diarrhea: Consider octreotide 100 μg three times daily 1
  • For IBS-D: Consider antibiotics (rifaximin) for short courses 5
  • For IBS-C with severe symptoms: Consider combining secretagogues with osmotic laxatives 1

Treatment Algorithm

1. Initial approach: Dietary modifications + lifestyle changes
2. Add: Soluble fiber and/or peppermint oil
3. If inadequate response: Add symptom-specific medication
   • IBS-C: Polyethylene glycol → secretagogue (linaclotide preferred)
   • IBS-D: Loperamide → cholestyramine
4. For persistent symptoms: Add antispasmodic or gut-brain neuromodulator (TCA)
5. For refractory symptoms: Consider psychological therapies and multidisciplinary approach 1

Important Considerations and Caveats

• Medication timing: Linaclotide must be taken on an empty stomach, at least 30 minutes before the first meal of the day 2
• Monitoring: Review efficacy after 3 months and discontinue if no response 3
• Safety warning: Linaclotide is contraindicated in patients less than 2 years of age due to risk of serious dehydration 2
• Treatment expectations: Set realistic expectations as IBS is typically a chronic, relapsing condition requiring ongoing management 6
• Integrated care: An approach addressing both gastrointestinal symptoms and psychological aspects is considered the gold standard, especially for patients with comorbid anxiety or depression 1

When to Refer

• Consider referral to gastroenterology specialist for:
  • Atypical IBS presentations
  • Diagnostic uncertainty
  • Severe or refractory symptoms
  • Patient request for specialist opinion 1
• Consider referral to dietitian when:
  • Patient reports significant trigger foods
  • Dietary deficits are present
  • Food-related fear is pathological 1