What is the recommended dosing for Lomotil (diphenoxylate and atropine)?

Lomotil (Diphenoxylate-Atropine) Dosing Guidelines

The recommended adult dosing for Lomotil (diphenoxylate-atropine) is 2 tablets (5 mg diphenoxylate/0.05 mg atropine) 3-4 times daily initially, then reduced to maintenance dosing after diarrhea control is achieved. 1

Adult Dosing Regimen

Initial Treatment

• Starting dose: 2 tablets (5 mg diphenoxylate/0.05 mg atropine) 3-4 times daily
• Maximum daily dose: 8 tablets (20 mg diphenoxylate/0.2 mg atropine) per day 1

Maintenance Dosing

• After diarrhea control is achieved, reduce to lower effective dose
• Typical maintenance: 2 tablets twice daily

Special Considerations

Acute Diarrhea Management

• For acute non-infectious diarrhea: 2 mg PO every 2 hours during the day and 4 mg PO every 4 hours at night 1
• For refractory cases:
  • Consider alternative agents if no response after 48 hours
  • Loperamide is generally more effective than diphenoxylate with atropine for acute diarrhea 1

Safety Precautions

• Contraindications:

  • Obstructive jaundice
  • Diarrhea associated with pseudomembranous enterocolitis or enterotoxin-producing bacteria
  • Children under 2 years of age

• Important warnings:

  • Rule out infectious causes before initiating therapy
  • Use with caution in patients with hepatic dysfunction
  • Potential for abuse due to diphenoxylate (opioid component) 2

Monitoring

• Assess response within 48 hours
• Monitor for signs of anticholinergic effects (dry mouth, blurred vision, urinary retention)
• Watch for CNS depression, especially with higher doses

Alternative Treatments for Refractory Cases

If diarrhea persists despite Lomotil therapy:

1. Consider loperamide (more effective than diphenoxylate with atropine) 1
2. For severe cases, octreotide 500 μg subcutaneously three times daily may be considered 1
3. Other options include psyllium seeds, codeine, or morphine in severe cases 1

Pediatric Considerations

Lomotil should be used with extreme caution in children. Pediatric poisonings have been reported with as little as 1-2 tablets, causing significant opioid toxicity and respiratory depression 3, 4, 5. The use of Lomotil as an antidiarrheal agent in children is difficult to justify due to safety concerns 5.

Common Pitfalls

1. Failing to rule out infectious diarrhea before initiating therapy
2. Exceeding maximum recommended daily dose
3. Prolonged use without attempting dose reduction
4. Underestimating potential for dependence with long-term use
5. Using in pediatric patients where risks generally outweigh benefits

Remember that diphenoxylate with atropine is generally less effective than loperamide for acute diarrhea 1, and should be considered a second-line agent for most cases of non-infectious diarrhea.