Prescription Imodium Dosing for Diarrhea
For adults with acute diarrhea, start loperamide at 4 mg initially, followed by 2 mg after each unformed stool, not exceeding 16 mg per day. 1, 2
Adult Dosing for Acute Diarrhea
- Initial dose: 4 mg (two 2-mg capsules) followed by 2 mg after each loose stool, with a maximum of 16 mg (eight capsules) daily 1, 2
- This dosing applies to adults and pediatric patients 13 years and older 2
- Clinical improvement typically occurs within 48 hours 2
- Combine with adequate oral hydration and dietary modifications (avoid spices, coffee, alcohol, high insoluble fiber foods, and consider limiting milk/dairy except yogurt and firm cheeses) 1
Adult Dosing for Chronic Diarrhea
- Start with the same initial approach: 4 mg followed by 2 mg after each unformed stool until controlled 2
- Once optimal daily dosage is established, it may be given as a single daily dose or divided doses 2
- Average maintenance dosage is 4-8 mg daily, with a maximum of 16 mg per day 2
- If no improvement after 10 days at 16 mg daily, further administration is unlikely to help 2
Pediatric Dosing (Ages 2-12 Years)
Loperamide is contraindicated in children under 2 years due to risks of respiratory depression and cardiac adverse reactions 2
- Ages 2-5 years (13-20 kg): 1 mg three times daily on first day (3 mg total), then 1 mg per 10 kg after each loose stool 2
- Ages 6-8 years (20-30 kg): 2 mg twice daily on first day (4 mg total), then adjust based on response 2
- Ages 8-12 years (>30 kg): 2 mg three times daily on first day (6 mg total), then adjust based on response 2
- Use liquid formulation (1 mg/5 mL) for children 2-5 years 2
Critical Safety Considerations
- Never exceed 16 mg daily in any patient due to serious cardiac adverse reaction risks 1, 2
- Avoid in bloody diarrhea or suspected dysentery without antibiotic coverage 1
- Avoid in grade 3-4 immunotherapy-induced diarrhea 1
- Avoid in neutropenic enterocolitis as it may worsen ileus 1
- Use caution in elderly patients, especially those on QT-prolonging medications (Class IA or III antiarrhythmics) 2
- Use caution in hepatic impairment due to reduced metabolism and increased systemic exposure 2
When to Escalate Care
- Hospitalization may be required for complicated diarrhea with fever, moderate-to-severe abdominal cramping, bloody stools, or signs of dehydration 1
- In these cases, loperamide can still be used at standard dosing alongside IV fluids, and potentially antibiotics or octreotide in severe cases 1
- Early initiation of loperamide is important to prevent progression to more severe diarrhea 3
Special Clinical Contexts
For chemotherapy-induced diarrhea, the same dosing applies (4 mg initially, then 2 mg every 4 hours or after each unformed stool, maximum 16 mg daily), though patients with grade 3-4 diarrhea may require more aggressive therapy such as octreotide 3, 1, 4