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

Treatment Options for Irritable Bowel Syndrome (IBS)

Treatment of IBS should follow a step-wise approach, beginning with dietary modifications and lifestyle changes, followed by targeted pharmacotherapy based on predominant symptoms, and advancing to neuromodulators and psychological therapies for refractory cases. 1

First-Line Treatments

Dietary Modifications

• Establish baseline fiber intake and gradually increase to 25g/day for constipation 1
• Consider a low FODMAP diet implemented by a trained dietitian for significant symptom reduction 1
• Reduce intake of trigger foods such as:
  • Spicy foods
  • Caffeine
  • Alcohol
  • Gas-producing foods high in fiber, lactose, or fructose 1
• Mediterranean diet may benefit patients with psychological-predominant symptoms 1
• BRAT diet (bread, rice, applesauce, toast) can help manage mild to moderate diarrhea 1

Symptom-Specific Pharmacotherapy

For IBS with Constipation (IBS-C)

1. Add soluble fiber and/or peppermint oil
2. If inadequate response, add polyethylene glycol
3. If still inadequate, add a secretagogue (linaclotide preferred based on efficacy) 1

For IBS with Diarrhea (IBS-D)

• Antidiarrheals for symptom control
• Antispasmodics for abdominal pain (dicyclomine)
• Tricyclic antidepressants (TCAs) are particularly effective 1
• 5-HT3 receptor antagonists like alosetron for women with severe diarrhea-predominant IBS who have not responded to conventional therapy 2
  • Caution: Alosetron carries a boxed warning for serious gastrointestinal adverse reactions including ischemic colitis and serious complications of constipation 2
• Other options include rifaximin, eluxadoline, and cholestyramine (for bile salt malabsorption) 1

Second-Line Treatments

Neuromodulators

• Tricyclic antidepressants (TCAs) are strongly recommended as second-line therapy with moderate quality evidence 1
  • Particularly effective for IBS-D and pain-predominant symptoms
  • Show significant efficacy for both IBS symptoms and depression
  • Continue for at least 6 months in responders 1
• The American Gastroenterological Association explicitly suggests against using SSRIs for IBS management (conditional recommendation, low certainty) 1
• Serotonin-norepinephrine reuptake inhibitors (SNRIs) may have greater effects on abdominal pain than SSRIs 1

Additional Pharmacotherapy

• Peppermint oil may improve global symptoms and abdominal pain in patients with IBS-D 1
• Short-term course of nonabsorbable antibiotics may improve global IBS symptoms, particularly in diarrhea-predominant IBS 3
• Some probiotics appear to have potential benefit in improving global IBS symptoms 3

Third-Line Treatments

Psychological Therapies

• Cognitive Behavioral Therapy (CBT) can be effective in 4-12 sessions 1
• Gut-directed hypnotherapy can focus on somatic awareness and down-regulation of pain sensations 1
• Mindfulness-based stress reduction can improve specific symptoms like constipation, diarrhea, bloating, and gastrointestinal-specific anxiety 1
• Acceptance and commitment therapy pairs acceptance and mindfulness strategies with behavior change techniques 1

Treatment Algorithm

1. Dietary modifications and lifestyle changes
2. Add soluble fiber and/or peppermint oil
3. If inadequate response, add symptom-specific medications:
   • For IBS-C: polyethylene glycol, then secretagogues
   • For IBS-D: antidiarrheals, antispasmodics
4. For persistent symptoms, add neuromodulators (preferably TCAs)
5. For severe or refractory symptoms, consider psychological therapies and multidisciplinary approach 1

Monitoring and Follow-up

• Use a symptom diary to identify triggers and monitor response to treatment 1
• Assess treatment response after 4+ weeks for first-line treatments 1
• Review efficacy after 3 months of treatment and discontinue if no response 1
• Consider referral to a gastroenterologist when:
  • Diagnostic uncertainty exists
  • Symptoms are severe or refractory to first-line treatments
  • The patient requests a specialist opinion 1

Important Cautions

• Discontinue alosetron immediately if constipation or symptoms of ischemic colitis develop 2
• Never resume alosetron in patients who develop ischemic colitis 2
• Monitor patients on TCAs for side effects
• For patients on low FODMAP diet, ensure nutritional adequacy through careful monitoring 1
• Alosetron is indicated only for women with severe diarrhea-predominant IBS who have not responded adequately to conventional therapy 2