Recommended Dosage of Imodium (Loperamide)
The recommended initial dose of Imodium (loperamide) is 4 mg (two capsules) followed by 2 mg (one capsule) after each unformed stool, with a maximum daily dose of 16 mg (eight capsules). 1
Adult Dosing Guidelines
Acute Diarrhea
- Initial dose: 4 mg (two capsules) 2, 1
- Maintenance: 2 mg after each loose stool 1
- Maximum daily dose: 16 mg (eight capsules) 2, 1
- Clinical improvement is usually observed within 48 hours 1
Chronic Diarrhea
- Initial dose: 4 mg (two capsules) followed by 2 mg after each unformed stool until diarrhea is controlled 1
- Average daily maintenance dosage: 4 to 8 mg (two to four capsules) 1
- Maximum daily dose: 16 mg (eight capsules) 1
- If no improvement after 10 days at maximum dose, symptoms are unlikely to be controlled with further administration 1
Special Populations
Elderly Patients
- No dose adjustment required for elderly patients 1
- Caution advised in elderly patients taking drugs that can prolong QT interval 1
- Avoid in elderly patients with risk factors for Torsades de Pointes 1
Renal Impairment
- No dosage adjustment required for patients with renal impairment 1
- Drug and metabolites are mainly excreted in feces 1
Timing Considerations
- Loperamide takes 1-2 hours to reach therapeutic effect 2
- Space additional doses accordingly to avoid rebound constipation 2
Efficacy in Different Scenarios
- More effective for mild to moderate diarrhea (84% response rate) compared to severe diarrhea (52% response rate) 3
- Significantly reduces number of unformed bowel movements compared to bismuth subsalicylate 4
- Provides faster relief of acute nonspecific diarrhea than bismuth subsalicylate 4
Important Precautions
- If diarrhea worsens or is accompanied by fever, moderate to severe abdominal pain, or bloody diarrhea, antibiotics should be considered instead 2
- Avoid in patients with suspected complicated diarrhea (sepsis, neutropenia, bleeding or dehydration) 2
- Anticholinergic, antidiarrheal, and opioid agents should be avoided in patients with ileus 2
Combination Therapy
- For cancer patients with chemotherapy-induced diarrhea, loperamide is the first-line treatment for uncomplicated cases 2, 5
- For more severe cases, octreotide may be more effective (starting dose 100-150 μg s.c./i.v. three times daily) 2
Remember that loperamide is contraindicated in children under 2 years of age due to risks of respiratory depression and serious cardiac adverse reactions 1.