What are the recommended treatments for managing Irritable Bowel Syndrome (IBS) onset?

Management of Irritable Bowel Syndrome at Onset

Begin with regular exercise and first-line dietary advice for all patients, followed by soluble fiber supplementation (ispaghula 3-4 g/day, titrated gradually), and reserve pharmacological treatments for symptom-specific management when initial measures fail after 4-6 weeks.

Initial Patient Education and Expectations

• Explain 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 rather than ordering extensive testing once diagnosis is established 2
• Introduce the concept of the gut-brain axis and how it is affected by diet, stress, and emotional responses to symptoms 3

First-Line Lifestyle Modifications (For All Patients)

• Prescribe regular physical exercise to all patients with IBS as the foundation of treatment 1, 3, 2, 4
• Provide first-line dietary advice including balanced diet with adequate fiber intake, regular time for defecation, and proper sleep hygiene 1, 2
• Avoid IgG antibody-based food elimination diets as they lack evidence and may lead to unnecessary dietary restrictions 1, 2

First-Line Dietary Interventions

• Start soluble fiber (ispaghula/psyllium) at 3-4 g/day and build up gradually to avoid bloating for global symptoms and abdominal pain 1, 3, 4
• Avoid insoluble fiber (wheat bran) as it consistently worsens symptoms, particularly bloating 1, 2, 4
• Do not recommend gluten-free diets unless celiac disease has been confirmed 1, 3

Second-Line Dietary Therapy (If First-Line Fails After 4-6 Weeks)

• Refer to a trained dietitian for a supervised low FODMAP diet delivered in three phases: restriction, reintroduction, and personalization 1, 3, 4
• Reintroduce FODMAPs according to tolerance under dietitian supervision 1

Symptom-Specific Pharmacological Treatment

For Abdominal Pain and Cramping

• Use antispasmodics (such as dicyclomine or mebeverine) as first-line pharmacological therapy for abdominal pain, particularly when symptoms are meal-related 1, 2, 4
• Common side effects include dry mouth, visual disturbance, and dizziness 1
• Peppermint oil may be used as an alternative antispasmodic 3, 2, 4

For Diarrhea-Predominant Symptoms (IBS-D)

• Prescribe loperamide 2-4 mg up to four times daily (either regularly or prophylactically) to reduce stool frequency, urgency, and fecal soiling 1, 3, 2
• Titrate the dose carefully as abdominal pain, bloating, nausea, and constipation are common and may limit tolerability 1

For Constipation-Predominant Symptoms (IBS-C)

• Increase dietary fiber to 25 g/day or use ispaghula/psyllium as described above 3, 2
• Consider polyethylene glycol (osmotic laxative) if fiber supplementation is insufficient, titrating the dose according to symptoms 3

Probiotics as Adjunctive First-Line Therapy

• Trial probiotics for 12 weeks for global symptoms and abdominal pain, though no specific species or strain can be recommended 1, 3, 2
• Discontinue if there is no improvement in symptoms after 12 weeks 1, 3

Second-Line Pharmacological Treatment (For Refractory Symptoms After 3 Months)

For Persistent Abdominal Pain and Global Symptoms

• Initiate tricyclic antidepressants (amitriptyline 10 mg once daily at bedtime) and titrate slowly to a maximum of 30-50 mg once daily 1, 3, 2, 4
• Provide careful explanation that these are used as gut-brain neuromodulators, not for depression 1, 3
• Counsel patients about side effects including dry mouth, drowsiness, and constipation 1
• Continue for at least 6 months if the patient reports symptomatic response 3

For IBS-D Refractory to Loperamide

• Consider 5-HT3 receptor antagonists (ondansetron titrated from 4 mg once daily to maximum 8 mg three times daily) in secondary care 1, 3
• Constipation is the most common side effect 1
• Rifaximin is an alternative second-line option, though its effect on abdominal pain is limited 1, 3

For IBS-C Refractory to Fiber and Osmotic Laxatives

• Prescribe linaclotide as the most efficacious secretagogue available for IBS-C in secondary care 1, 3
• Warn patients that diarrhea is a common side effect 1
• Lubiprostone (8 mcg twice daily with food) is an alternative that is less likely to cause diarrhea 1, 5

Alternative Neuromodulator

• Consider selective serotonin reuptake inhibitors (SSRIs) if tricyclic antidepressants are not tolerated or if comorbid anxiety/depression is present 1, 3, 4

Psychological Therapies (For Symptoms Persisting After 12 Months of Pharmacological Treatment)

• Refer for IBS-specific cognitive behavioral therapy or gut-directed hypnotherapy when symptoms persist despite 12 months of pharmacological treatment 1, 3, 2, 4
• Consider earlier referral for patients who relate symptom exacerbations to stressors or have associated anxiety/depression 3, 2

Critical Pitfalls to Avoid

• Do not pursue colonoscopy or extensive testing 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, 2
• Avoid opioids for chronic abdominal pain management due to risks of dependence and complications 3
• Do not recommend IgG-based food allergy testing as true food allergy is rare in IBS 2
• Recognize that complete symptom resolution is often not achievable; the goal is symptom relief and improved quality of life 3

Follow-Up and Monitoring

• Review treatment efficacy after 3 months and discontinue if no response 3
• Periodically assess the need for continued therapy 5
• Build collaborative links with gastroenterology dietitians and gastropsychologists to coordinate care 2