What is the dosing of Immodium (Loperamide) for diarrhea?

Loperamide (Immodium) Dosing for Diarrhea

For adults with acute diarrhea, start with 4 mg (two capsules) initially, followed by 2 mg (one capsule) after each unformed stool, with a maximum daily dose of 16 mg (eight capsules). 1

Standard Adult Dosing Algorithm

Initial Dose

• 4 mg (two capsules) as a loading dose 2, 1
• This loading dose is critical for achieving therapeutic effect more rapidly 2

Maintenance Dosing

• 2 mg after each unformed stool 2, 1
• Alternative schedule: 2 mg every 4 hours (particularly for cancer-related or complicated diarrhea) 2
• Maximum: 16 mg per day (eight capsules) 2, 1

Important Timing Consideration

• Allow 1-2 hours between doses for loperamide to reach therapeutic effect before taking additional doses to avoid rebound constipation 2

Pediatric Dosing (Ages 2-12 Years)

Loperamide is contraindicated in children under 2 years of age due to risks of respiratory depression and cardiac adverse reactions. 1

First Day Dosing by Age/Weight:

• 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

Subsequent Days:

• 1 mg per 10 kg body weight after each loose stool only 1
• Do not exceed first-day maximum dosages 1

Context-Specific Dosing

Chronic Diarrhea

• Start with 4 mg initially, then 2 mg after each unformed stool until controlled 1
• Once controlled, reduce to maintenance dose of 4-8 mg daily (can be given as single daily dose) 1, 3
• Maximum remains 16 mg per day 1
• If no improvement after 10 days at 16 mg/day, further treatment unlikely to help 1

Cancer/Radiation-Induced Diarrhea

• 4 mg initially, then 2 mg every 4 hours or after each unformed stool (maximum 16 mg/day) 2
• Combine with oral hydration and dietary modifications (eliminate lactose, reduce insoluble fiber) 2

Traveler's Diarrhea (Mild)

• 4 mg initially (two tablets), then 2 mg after each loose stool up to 16 mg/day 2
• Reserve for mild diarrhea causing little interference with activities 2

Critical Safety Warnings

Absolute Contraindications - STOP Loperamide If:

• Fever develops 2, 4
• Moderate to severe abdominal pain occurs 2, 4
• Bloody diarrhea appears 2, 4
• Symptoms worsen despite treatment 2

Cardiac Risk

• Never exceed 16 mg per day - higher doses increase risk of QT prolongation and Torsades de Pointes 4, 1
• Avoid in elderly patients taking Class IA or III antiarrhythmics 1

Special Populations

• Hepatic impairment: Use with caution; systemic exposure may increase due to reduced metabolism 1
• Renal impairment: No dose adjustment needed 1
• Elderly: No dose adjustment required, but increased susceptibility to QT effects 1

When to Escalate Treatment

• If diarrhea persists beyond 48 hours without improvement, consider antibiotic therapy 1
• For complicated diarrhea (with fever, dehydration, severe cramping), hospitalization and IV fluids may be needed alongside loperamide 2
• Combination therapy with rifaximin provides faster resolution (27 hours vs 69 hours with loperamide alone) for traveler's diarrhea 5