What is the initial treatment approach for adult males with irritable bowel syndrome (IBS)?

Treatment of Irritable Bowel Syndrome in Men

Begin with lifestyle modifications and dietary interventions, then escalate to pharmacological therapy based on predominant symptoms (pain, diarrhea, or constipation), reserving neuromodulators and psychological therapies for refractory cases. 1

Initial Management and Patient Education

Establish the diagnosis positively in men under 45 meeting Rome criteria without alarm features to avoid unnecessary testing. 1 Provide clear explanation that IBS is a disorder of gut-brain interaction with a benign but relapsing/remitting course. 1 Address specific concerns directly—particularly fears about cancer or serious disease—as this therapeutic relationship forms the foundation of successful management. 1

Consider using a symptom diary for 2 weeks to identify triggers and guide treatment decisions, as this actively involves patients in disease management. 1, 2

First-Line Treatment: Lifestyle and Dietary Modifications

Recommend regular physical exercise to all men with IBS, as this provides significant benefits for global symptom management. 1 This should be the foundation of treatment before pharmacological interventions. 1

Dietary Approach

• Start with soluble fiber (ispaghula/psyllium) at 3-4 g/day, building up gradually to avoid bloating and gas. 1 This is effective for both global symptoms and abdominal pain. 1
• Avoid insoluble fiber (wheat bran) as it consistently worsens symptoms, particularly bloating. 1
• Identify and reduce excessive intake of lactose, fructose, sorbitol, caffeine, or alcohol if diarrhea is predominant. 1
• If symptoms persist after 4-6 weeks of first-line measures, consider a supervised trial of low FODMAP diet delivered in three phases (restriction, reintroduction, personalization) by a trained dietitian. 1 This approach is particularly effective for moderate to severe symptoms but requires professional guidance to avoid nutritional deficits. 1

Do not recommend IgG antibody-based food elimination diets or gluten-free diets unless celiac disease has been confirmed. 1

Pharmacological Treatment Based on Predominant Symptoms

For Abdominal Pain

Use antispasmodics with anticholinergic properties (dicyclomine) as first-line therapy for abdominal pain, particularly when symptoms are meal-related. 1 Common side effects include dry mouth, visual disturbance, and dizziness. 1

Peppermint oil may be useful as an alternative antispasmodic, though evidence is more limited. 1

For Diarrhea-Predominant IBS (IBS-D)

Prescribe loperamide 4-12 mg daily either regularly or prophylactically to effectively slow intestinal transit and reduce stool frequency, urgency, and fecal soiling. 1 Use divided doses, preferably with a morning dose before breakfast (2-6 mg) and potentially again later in the day when symptoms are prominent. 1, 2

For refractory diarrhea, use rifaximin 550 mg three times daily for 14 days as a second-line agent. 3 In clinical trials, 47% of men responded to rifaximin with improvement in both abdominal pain (≥30% reduction) and stool consistency (≥50% reduction in loose/watery stools) during the month following treatment. 3 The median time to symptom recurrence after initial response was 10 weeks. 3 Upon recurrence, repeat treatment with rifaximin showed 38% response rate versus 31% with placebo. 3

Consider 5-HT3 receptor antagonists as additional second-line options for refractory diarrhea. 1

For Constipation-Predominant IBS (IBS-C)

Start with increasing dietary fiber or soluble fiber supplements (ispaghula/psyllium) at 3-4 g/day, gradually increased. 1

If constipation persists, start polyethylene glycol (osmotic laxative), titrating the dose according to symptoms. 1 Abdominal pain is the most common side effect. 1

For refractory constipation after first-line therapies fail, prescribe linaclotide 290 mcg once daily on an empty stomach as the preferred second-line agent. 1 This is the most effective FDA-approved secretagogue for IBS-C, addressing both abdominal pain and constipation. 1 Diarrhea is a common side effect as the mechanism of action. 1

Lubiprostone 8 mcg twice daily is an alternative secretagogue if linaclotide is not tolerated, though nausea is more common. 1

Second-Line Treatment: Neuromodulators for Refractory Symptoms

Prescribe tricyclic antidepressants (TCAs) starting with amitriptyline 10 mg once daily at bedtime, titrated slowly to 30-50 mg daily, for men with refractory abdominal pain and global symptoms despite first-line therapies. 1, 4 TCAs are the most effective first-line pharmacological treatment for mixed IBS symptoms and refractory pain. 1

Start at low doses (10 mg once daily) and increase slowly to maximum 30-50 mg once daily. 1 Explain clearly that these are used for pain modulation via gut-brain interaction, not for depression. 1 Continue TCAs for at least 6 months if the patient reports symptomatic improvement. 1

Important caveat: TCAs may worsen constipation through anticholinergic effects, so use cautiously in IBS-C and ensure adequate laxative therapy is in place. 1

If there is concurrent mood disorder, use a selective serotonin reuptake inhibitor (SSRI) at therapeutic doses instead of low-dose TCAs, because low-dose TCAs are unlikely to address psychological symptoms. 4 SSRIs may be effective as an alternative when TCAs are not tolerated or worsen constipation. 1

Psychological Therapies for Persistent Symptoms

Refer for IBS-specific cognitive behavioral therapy or gut-directed hypnotherapy when symptoms persist despite pharmacological treatment for 12 months. 1 These brain-gut behavior therapies are specifically designed for IBS and differ from psychological therapies that target depression and anxiety alone. 1

Refer to a gastropsychologist if IBS symptoms or their impact are moderate to severe, the patient accepts that symptoms are related to gut-brain dysregulation, and has time to devote to learning new coping strategies. 1

Multidisciplinary Care Coordination

Build collaborative links with gastroenterology dietitians and gastropsychologists to coordinate high-quality care. 1 Refer to a dietitian if the patient reports considerable intake of foods that trigger IBS symptoms, requests dietary advice, or has dietary deficits or nutrition red flags (avoidance of multiple food groups, unintentional weight loss ≥5% in previous 6 months, or nutrient deficiency). 4

Promote patient empowerment through education and psychoeducation using handouts, self-help books, websites, and apps, targeting physical activity, sleep hygiene, mindful eating, and assertive communication. 4 Self-management techniques improve IBS symptoms and quality of life in the short term. 4

Treatment Monitoring and Adjustment

Review treatment efficacy after 3 months and discontinue ineffective medications. 1 Recognize that symptoms may relapse and remit over time, requiring periodic adjustment of treatment strategy. 1

Critical Pitfalls to Avoid

• Avoid extensive testing once IBS diagnosis is established in men under 45 without alarm features. 1
• Do not prescribe anticholinergic antispasmodics like dicyclomine for IBS-C, as they reduce intestinal motility and will worsen constipation. 1
• Avoid opioids for chronic abdominal pain management due to risks of dependence and complications. 4
• Do not continue ineffective therapies indefinitely; reassess at 3 months. 1