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

Treatment Options for Irritable Bowel Syndrome (IBS)

The most effective approach to treating IBS involves a step-wise algorithm starting with dietary modifications, followed by targeted pharmacological interventions based on predominant symptoms, and psychological therapies for refractory cases. 1

First-Line Treatments

Dietary Interventions

• Low FODMAP diet: Recommended for moderate to severe symptoms, implemented by a trained dietitian 1
• Soluble fiber supplementation: Start with ispaghula 3-4g/day and gradually increase for constipation-predominant IBS 1
• Eliminate trigger foods: Reduce intake of gas-producing foods high in fiber, lactose, or fructose 1
• Consider Mediterranean diet for patients with psychological-predominant symptoms 1

Symptom-Specific Medications

For Abdominal Pain

• Antispasmodics (e.g., dicyclomine): First-line treatment for abdominal pain 1
• Peppermint oil: Effective for pain relief with high efficacy compared to other interventions 1, 2

For IBS with Constipation (IBS-C)

• Lubiprostone: FDA-approved for IBS-C in women at least 18 years old at a dose of 8 mcg twice daily 3
• Polyethylene glycol for inadequate response to fiber 1
• Secretagogues (linaclotide preferred) for persistent symptoms 1

For IBS with Diarrhea (IBS-D)

• Loperamide: Initial dose of 4 mg followed by 2 mg every 4 hours or after every unformed stool (max 16 mg/day) 1
• Alosetron: For severe IBS-D that hasn't responded to other treatments (women only) 1
• Rifaximin (550mg twice daily for 1-2 weeks) if small intestinal bacterial overgrowth (SIBO) is suspected 1

Second-Line Treatments

Neuromodulators

• Tricyclic antidepressants (e.g., amitriptyline 10-50mg at bedtime): For pain with sleep disturbance 1
• SNRIs (e.g., duloxetine): Consider for visceral pain 1
• SSRIs: May be used for predominant anxiety/depression, though less effective for pain 1
• Mirtazapine: Consider for refractory nausea and vomiting 1

Psychological Therapies

• Cognitive Behavioral Therapy (CBT): Effective in 4-12 sessions, focusing on pain catastrophizing and visceral anxiety 1
• Gut-directed hypnotherapy: Focuses on somatic awareness and down-regulation of pain sensations 1
• Mindfulness-based stress reduction: Improves specific symptoms like constipation, diarrhea, bloating 1
• Acceptance and commitment therapy: Pairs acceptance strategies with behavior change techniques 1

Treatment Algorithm

1. Start with dietary modifications and lifestyle changes
2. Add soluble fiber and/or peppermint oil
3. If inadequate response, add polyethylene glycol for constipation or loperamide for diarrhea
4. For persistent symptoms, add secretagogues for constipation (linaclotide preferred)
5. Consider adding antispasmodics or gut-brain neuromodulators for ongoing symptoms
6. For severe or refractory symptoms, implement psychological therapies 1

Important Considerations

Monitoring and Follow-up

• Use a symptom diary to identify triggers and monitor treatment response 1
• Review efficacy after 3 months and discontinue ineffective treatments 1
• Complete symptom resolution is often not achievable; set realistic expectations 1

When to Refer

• Refer to a gastroenterologist when diagnostic uncertainty exists, symptoms are severe or refractory to first-line treatments 1
• Consider referral to a dietitian for patients with high intake of trigger foods, dietary deficits, or food-related fear 1

Cautions

• Lubiprostone: May cause nausea (take with food), diarrhea, syncope, and hypotension 3
• Antispasmodics: Anticholinergic side effects may limit use in some patients 4
• Alosetron: Limited by risk of severe constipation and ischemic colitis 4

Remember that the brain-gut axis plays a crucial role in symptom perception, with factors such as anxiety and hypervigilance contributing to symptom severity 1. Coordinating care between gastroenterology and mental health providers is essential for patients with mental health comorbidities 1.