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

Management of Irritable Bowel Syndrome (IBS)

Start all IBS patients on regular physical exercise and soluble fiber supplementation (psyllium 3-4 g/day, gradually increased), then add symptom-specific pharmacotherapy based on the predominant subtype, reserving psychological therapies for refractory cases after 12 months of failed medical management. 1

Initial Patient Education and Expectation Setting

• Explain to patients that IBS is a disorder of gut-brain interaction with a benign but relapsing/remitting course to establish realistic expectations and reduce anxiety 1
• Address patient fears directly and identify their beliefs about the condition rather than ordering extensive testing once diagnosis is established 1
• Avoid pursuing extensive diagnostic workup in patients under 45 without alarm features (unintentional weight loss ≥5%, blood in stool, fever, anemia, family history of colon cancer or inflammatory bowel disease) 1

First-Line Management: Lifestyle and Dietary Modifications (For All Patients)

Exercise

• Recommend regular physical activity to all IBS patients as this provides significant benefits for symptom management 1

Fiber Supplementation

• Start soluble fiber (ispaghula/psyllium) at low doses of 3-4 g/day and gradually increase to avoid bloating and gas 1
• Avoid insoluble fiber (wheat bran) as it consistently worsens symptoms, particularly bloating 1

Low FODMAP Diet (Second-Line Dietary Intervention)

• Refer to a trained dietitian for a supervised trial of low FODMAP diet delivered in three phases: restriction, reintroduction, and personalization 1, 2
• This diet should only be implemented under supervision to prevent nutritional deficiencies 1
• Do not recommend gluten-free diets unless celiac disease has been confirmed 1

Probiotics

• Trial probiotics for 12 weeks for global symptoms and bloating; discontinue if no improvement occurs 1

Pharmacological Treatment by IBS Subtype

IBS with Diarrhea (IBS-D)

First-line: Loperamide 4-12 mg daily (either regularly or prophylactically before activities) to reduce stool frequency, urgency, and fecal soiling 1

Second-line: Rifaximin 550 mg three times daily for 14 days is effective for adequate relief of IBS symptoms (41% vs 31% placebo, p=0.0125) and can be repeated for symptom recurrence 3

Antispasmodics: Use anticholinergic agents like dicyclomine for meal-related abdominal pain 1

IBS with Constipation (IBS-C)

First-line: Soluble fiber (psyllium) 3-4 g/day, gradually increased 1

Second-line: Polyethylene glycol (osmotic laxative), titrating dose according to symptoms 4

Third-line: Linaclotide is the most effective secretagogue for IBS-C when first-line therapies fail 4

Antispasmodics: Dicyclomine for abdominal pain, though anticholinergic side effects (dry mouth, visual disturbance, dizziness) are common 1

IBS with Mixed Symptoms (IBS-M)

First-line: Tricyclic antidepressants (amitriptyline 10 mg once daily at bedtime, titrated slowly to 30-50 mg daily) are the most effective pharmacological treatment for mixed symptoms 1, 4

Alternative: Selective serotonin reuptake inhibitors (SSRIs) may be effective when TCAs are not tolerated 4

Symptom-specific agents: Use loperamide for diarrhea episodes and fiber/osmotic laxatives for constipation episodes 4

Pain Management Across All Subtypes

• Antispasmodics (dicyclomine) are first-line for abdominal pain, particularly when symptoms are meal-related 1
• Peppermint oil may be useful as an alternative antispasmodic 1
• Tricyclic antidepressants (amitriptyline 10-50 mg daily) are effective for refractory abdominal pain after first-line therapies fail 1

Psychological Therapies (For Refractory Cases)

• Consider IBS-specific cognitive behavioral therapy or gut-directed hypnotherapy when symptoms persist despite pharmacological treatment for 12 months 1, 2
• These therapies modify maladaptive cognitive or affective processes that amplify symptom perception 2

Critical Pitfalls to Avoid

• Do not order IgG-based food allergy testing, as true food allergy is rare in IBS 1
• Avoid recommending gluten-free diets without confirmed celiac disease 1
• Do not prescribe opioids for chronic abdominal pain, as they can worsen IBS symptoms and lead to narcotic bowel syndrome 5
• Recognize that TCAs may worsen constipation in IBS-C patients; ensure adequate laxative therapy is in place if using TCAs in this subtype 4
• Avoid implementing restrictive diets without dietitian supervision, which can lead to nutritional deficiencies 5

Treatment Algorithm Summary

1. All patients: Exercise + soluble fiber (psyllium 3-4 g/day, gradually increased) 1
2. Add symptom-specific therapy:
   • IBS-D: Loperamide 4-12 mg daily → Rifaximin 550 mg TID × 14 days if inadequate response 1, 3
   • IBS-C: Polyethylene glycol → Linaclotide if inadequate response 4
   • IBS-M: Tricyclic antidepressants (amitriptyline 10-50 mg daily) 1
3. For abdominal pain: Antispasmodics (dicyclomine) or peppermint oil 1
4. If symptoms persist after 12 months: Refer for IBS-specific cognitive behavioral therapy or gut-directed hypnotherapy 1