What is the recommended dose of Loperamide (Loperamide) for adults and children?

Loperamide Dosing Recommendations

For adults and children 13 years and older, start with 4 mg initially, then 2 mg after each unformed stool, not exceeding 16 mg per day; for children 2-12 years, use age-based dosing starting at 1-2 mg three times daily on day one, followed by 1 mg per 10 kg after loose stools. 1

Adult Dosing (≥13 Years)

Acute Diarrhea

• Initial dose: 4 mg (two capsules), followed by 2 mg after each unformed stool 2, 3, 1
• Alternative approach: 2 mg every 2-4 hours if preferred over the "after each stool" method 2, 3
• Maximum daily dose: 16 mg (eight capsules) 2, 3, 1
• Clinical improvement typically occurs within 48 hours 1

Chronic Diarrhea

• Same initial dosing: 4 mg followed by 2 mg after each unformed stool until controlled 1
• Once optimal dosage is established, may be given as single daily dose or divided doses 1
• Average maintenance dose: 4-8 mg per day 1
• Maximum remains 16 mg per day 1
• If no improvement after 10 days at 16 mg/day, further treatment unlikely to help 1

Pediatric Dosing (2-12 Years)

First Day Dosing Schedule

• Ages 2-5 years (13-20 kg): 1 mg three times daily (3 mg total) 1
• Ages 6-8 years (20-30 kg): 2 mg twice daily (4 mg total) 1
• Ages 8-12 years (>30 kg): 2 mg three times daily (6 mg total) 1
• For children 2-5 years, use liquid formulation (1 mg/5 mL) rather than capsules 1

Subsequent Days

• Give 1 mg per 10 kg body weight only after a loose stool 1
• Do not exceed the first day's total dosage 1

Critical Safety Considerations

Absolute Contraindications

• Children under 2 years of age due to respiratory depression and cardiac risks 1
• Grade 3-4 immunotherapy-induced diarrhea 2, 3
• Neutropenic enterocolitis (avoid all antimotility agents) 3

When to Avoid or Use Extreme Caution

• Bloody diarrhea or suspected dysentery without antibiotic coverage 3
• Fever, moderate to severe abdominal pain, or signs of severe dehydration warrant hospitalization with IV fluids rather than loperamide alone 2, 3
• Hepatic impairment (use cautiously due to reduced metabolism and increased systemic exposure) 1
• Elderly patients on QT-prolonging drugs (Class IA or III antiarrhythmics) 1

Cardiac Safety Warning

• Never exceed 16 mg per day—serious cardiac events including QT prolongation, torsades de pointes, cardiac arrest, and death can occur with supratherapeutic doses 2, 1
• The FDA warning primarily relates to abuse cases with doses of 64-1600 mg daily, far exceeding therapeutic dosing 4
• At recommended doses for chemotherapy-induced diarrhea, cardiac risk remains extremely low and is outweighed by risks of uncontrolled diarrhea 4

Essential Supportive Measures

• Ensure adequate fluid and electrolyte replacement 2, 3
• Implement dietary modifications: avoid lactose products, spices, coffee, alcohol, and high insoluble fiber foods 2, 3
• Consider avoiding milk and dairy except yogurt and firm cheeses 3

Common Pitfalls to Avoid

• Do not delay initiation—early intervention prevents progression to severe diarrhea 2
• Loperamide takes 1-2 hours to reach therapeutic effect, so space additional dosing accordingly to avoid rebound constipation 2
• Do not use in severe immunotherapy-induced colitis as it may worsen outcomes 2
• Monitor for signs of dehydration or worsening symptoms 2

Special Populations

Elderly

• No dose adjustment required 1
• More susceptible to QT interval effects—avoid concurrent QT-prolonging medications 1

Renal Impairment

• No dose adjustment needed (drug mainly excreted in feces) 1

Hepatic Impairment

• Use with caution due to potentially increased systemic exposure 1