What is the recommended dose of Lomotil (diphenoxylate hydrochloride with atropine sulfate)?

Recommended Dosage of Lomotil (Diphenoxylate with Atropine)

For adults with non-infectious diarrhea, diphenoxylate with atropine (Lomotil) is considered a second-line option after loperamide, with typical dosing of 2 tablets (5 mg) 3-4 times daily as needed. 1

Adult Dosing Guidelines

Lomotil is not a first-line treatment for diarrhea. The medication hierarchy is:

1. First-line: Loperamide (4 mg initially, then 2 mg after each loose stool, maximum 16 mg daily)
2. Second-line: Diphenoxylate with atropine (Lomotil)
3. Alternative options: Psyllium seeds, codeine, paregoric tincture of opium, or morphine

Specific Dosing for Adults

• Initial dose: 2 tablets (5 mg diphenoxylate/0.05 mg atropine)
• Frequency: 3-4 times daily as needed
• Maximum daily dose: 8 tablets (20 mg diphenoxylate/0.2 mg atropine)
• Timing: Most effective when administered approximately 30 minutes before meals and at bedtime 1

Pediatric Considerations

Lomotil use in children is controversial and generally not recommended due to safety concerns:

• High risk of toxicity: Children are particularly vulnerable to Lomotil toxicity 2, 3, 4
• Respiratory depression: The most threatening reaction in children 2
• Limited evidence: The American Academy of Pediatrics does not recommend diphenoxylate for children 5

If used in children (which should be done with extreme caution):

• Pediatric liquid formulation: 0.3 mg/kg/day divided into multiple doses 6
• Close monitoring required: For signs of respiratory depression or CNS effects

Important Precautions

• Duration limit: Discontinue if symptoms persist beyond 48 hours 5

• Contraindications:

  • High fever
  • Bloody stools
  • Infectious diarrhea
  • Severe dehydration (without appropriate rehydration)

• Risk factors:

  • Enhanced CNS depression when combined with alcohol or other CNS depressants
  • Abuse potential at high doses
  • May mask symptoms of more serious conditions 5

Special Populations

Short Bowel Syndrome Patients

• Higher doses may be required due to disrupted enterohepatic circulation
• Up to 16 tablets (32 mg) per day may be needed 1
• Most effective when administered 30 minutes before meals and at bedtime

Cancer Patients with Therapy-Associated Diarrhea

• Consider as an alternative when loperamide (first-line) is ineffective 1
• If both loperamide and diphenoxylate fail, octreotide at 500 μg TID SC may be considered 1

Monitoring and Follow-up

• Monitor stool output objectively to assess effectiveness
• Discontinue if no improvement after 48 hours
• Be alert for signs of toxicity: respiratory depression, CNS depression, atropine-like effects
• Consider alternative formulations (liquid) if solid dosage forms are not effective 1

Warning Signs of Toxicity

• Respiratory depression (most serious)
• CNS depression (drowsiness, coma)
• Atropine-like effects (flushing, fever, dry mouth)
• Treatment of overdose includes naloxone, activated charcoal, and supportive care 3, 7

Remember that loperamide is generally preferred over diphenoxylate with atropine due to its better safety profile and lack of addictive or sedative properties 1.