Treatment Options for Diarrhea-Predominant Irritable Bowel Syndrome (IBS-D)

Loperamide at doses of 4-12 mg daily is the most effective first-line treatment for IBS-D, significantly reducing stool frequency and urgency. 1

First-Line Treatments

Regular exercise should be recommended to all IBS-D patients as it provides significant benefits for symptom management 1
Provide clear dietary advice, including identification and reduction of excessive intake of lactose, fructose, sorbitol, caffeine, or alcohol in patients with diarrhea 1
Consider a trial of low FODMAP diet under supervision of a trained dietitian for patients with persistent symptoms 2
Soluble fiber (ispaghula/psyllium) may be beneficial, starting with low doses (3-4g/day) and gradually increasing to avoid bloating 2
Avoid insoluble fiber (wheat bran) as it may worsen symptoms in IBS-D patients 2

Loperamide at doses of 4-12 mg daily effectively slows intestinal transit and reduces stool frequency and urgency 1
Loperamide can be used both regularly or prophylactically (e.g., before going out) based on patient needs 1
Codeine (15-30 mg, 1-3 times daily) is effective for diarrhea but more likely to cause sedation and dependency 1

Antispasmodics with anticholinergic properties (like dicyclomine) show greater efficacy for pain relief compared to direct smooth muscle relaxants 1
Peppermint oil acts as an antispasmodic and may provide symptom relief 2
Common side effects include dry mouth, visual disturbances, and dizziness 2

Tricyclic antidepressants (TCAs) are effective for pain and global symptoms in IBS-D 1
Start TCAs at low doses (10 mg of amitriptyline at night) and titrate slowly by 10 mg/week according to response and tolerability 1
Continue TCAs for at least 6 months if the patient reports symptomatic improvement 2
Selective serotonin reuptake inhibitors (SSRIs) may be considered if TCAs are not tolerated 1

Rifaximin (Xifaxan) is FDA-approved for IBS-D in adults 3
- Non-absorbable antibiotic that modulates gut microbiota and reduces inflammation 4
- Administered as a 2-week course with repeat courses as needed for symptom recurrence 4
Eluxadoline (Viberzi) is FDA-approved for IBS-D in adults 5
- Mixed μ- and κ-opioid receptor agonist/δ-opioid antagonist that decreases GI motility and fluid secretion 4
- Administered as chronic daily therapy 4
Alosetron is approved only for women with severe IBS-D refractory to conventional therapy 4
- 5-HT3 antagonist that slows GI motility and reduces visceral pain 4

Approximately 10% of IBS-D patients show evidence of bile salt malabsorption and may respond to cholestyramine, particularly those with <5% retention on SeHCAT testing 1
Probiotics may improve global symptoms and abdominal pain; recommend a 12-week trial and discontinue if no improvement 2

Consider IBS-specific cognitive behavioral therapy or gut-directed hypnotherapy for patients with symptoms refractory to pharmacological treatment for 12 months 1
Simple relaxation therapy may be beneficial as an initial approach 2
Biofeedback can be especially helpful for patients with disordered defecation 2

Start with loperamide 4-12 mg daily for diarrhea control 1
Add antispasmodics (preferably with anticholinergic properties) for pain relief 1
If inadequate response after 4-6 weeks, consider:
- Trial of low FODMAP diet 2
- Addition of TCAs starting at 10 mg nightly 1
For persistent symptoms, consider FDA-approved medications:
- Rifaximin as a 2-week course 3
- Eluxadoline for ongoing therapy 5
For refractory cases, refer for psychological therapies 1

Review treatment efficacy after 3 months and discontinue ineffective medications 2
Avoid extensive testing once IBS-D diagnosis is established 2
Recognize that IBS is a disorder of gut-brain interaction requiring explanation of the gut-brain axis to patients 1
Acknowledge that symptoms may relapse and remit over time, requiring periodic adjustment of treatment strategy 1