Immodium (Loperamide) Dosing for Adults
For acute diarrhea in adults, start with 4 mg of loperamide immediately, followed by 2 mg after each unformed stool, with a maximum daily dose of 16 mg. 1
Standard Dosing Regimen
- Initial dose: 4 mg (two 2 mg capsules) 2, 3, 1
- Maintenance: 2 mg after each unformed stool 2, 3, 1
- Alternative interval: 2 mg every 2-4 hours (if preferred over the "after each stool" approach) 2, 4
- Maximum daily dose: 16 mg (eight capsules) 2, 3, 1
- Clinical improvement typically occurs within 48 hours 1
Essential Supportive Measures
- Ensure adequate fluid and electrolyte replacement 4, 1
- Avoid lactose-containing products, spices, coffee, and alcohol 3, 4
- Consider avoiding milk and dairy products except yogurt and firm cheeses 3
When to Avoid Loperamide
Absolute contraindications:
- Pediatric patients less than 2 years of age (risk of respiratory depression and cardiac adverse reactions) 1
- Grade 3-4 immunotherapy-induced diarrhea or colitis 2, 3, 4
- Bloody diarrhea or suspected dysentery without appropriate antibiotic coverage 3
Use with caution:
- Fever, moderate to severe abdominal pain, or bloody diarrhea (consider hospitalization with IV fluids instead) 4
- Hepatic impairment (systemic exposure may be increased) 1
- Elderly patients taking QT-prolonging drugs 1
Critical Pitfalls to Avoid
- Never exceed 16 mg daily - serious cardiac events can occur with supratherapeutic doses 4, 1
- Do not delay initiation - early intervention prevents progression to severe diarrhea 4
- Allow 1-2 hours for therapeutic effect before additional dosing to avoid rebound constipation 4
- Monitor for paralytic ileus when using high-dose loperamide, though this is rare 2
- In neutropenic enterocolitis, avoid loperamide as it may aggravate ileus 3
Chronic Diarrhea Dosing
- Start with 4 mg followed by 2 mg after each unformed stool until controlled 1
- Once optimal dosage is established, may administer as single daily dose or divided doses 1
- Average maintenance dosage: 4-8 mg daily 1
- Maximum: 16 mg daily 1
- If no improvement after 10 days at 16 mg daily, further administration unlikely to help 1
Special Populations
Elderly: No dose adjustment required, but avoid in those taking QT-prolonging medications 1
Renal impairment: No dose adjustment needed 1
Hepatic impairment: Use with caution due to reduced metabolism and increased systemic exposure 1