Can I use Lomotil (diphenoxylate) for chronic diarrhea?

Using Diphenoxylate (Lomotil) for Chronic Diarrhea

Diphenoxylate with atropine (Lomotil) can be used for chronic diarrhea, but it is generally less effective than loperamide and has more side effects, making it a second-line option for most patients with chronic diarrhea. 1

Mechanism and Efficacy

Diphenoxylate is a synthetic opioid agonist that:

• Decreases intestinal peristaltic activity
• Inhibits secretion in the gut
• Reduces fluid and electrolyte loss
• Increases stool consistency 2

The FDA has approved diphenoxylate with atropine as "adjunctive therapy in the management of diarrhea" 3. However, comparative studies have shown that:

• Diphenoxylate is significantly less effective than loperamide or codeine in producing solid stool in chronic diarrhea patients 4
• It is less effective at relieving urgency and fecal incontinence compared to loperamide 4
• Side effects, particularly central nervous system effects, are greater with diphenoxylate than with loperamide 4

Safety Considerations

Several important safety considerations exist when using diphenoxylate:

1. Controlled substance: Diphenoxylate is classified as a Schedule V controlled substance due to its relation to the narcotic analgesic meperidine 3

2. Potential for dependence: While addiction is unlikely at therapeutic doses, it is possible at high doses (100-300 mg/day for 40-70 days can produce opiate withdrawal symptoms) 3

3. Contraindications:

   • Should not be used in patients with high fever or bloody stools 1
   • Should be discontinued if symptoms persist beyond 48 hours 1
   • Not recommended for children 1

4. Drug interactions: May interact with other CNS depressants

Treatment Algorithm for Chronic Diarrhea

1. First-line therapy: Loperamide (more effective, fewer side effects) 5, 4

   • Initial dose: 4 mg followed by 2 mg after each loose stool
   • Maximum: 16 mg daily 1

2. Second-line options (if loperamide is ineffective or not tolerated):

   • Diphenoxylate with atropine (Lomotil)
   • Cholestyramine (particularly for bile acid diarrhea) 2
   • 5-HT3 receptor antagonists (for IBS with diarrhea) 2

3. For specific conditions:

   • Microscopic colitis: Consider budesonide 2
   • Small intestinal bacterial overgrowth: Consider rifaximin 2
   • Cancer treatment-induced diarrhea: Consider octreotide if loperamide fails 1

Common Pitfalls and Caveats

1. Masking serious conditions: Antiperistaltic agents like diphenoxylate may mask symptoms of more serious conditions that require specific treatment

2. Overuse: Continuing use beyond 48 hours when symptoms persist could delay appropriate diagnosis and treatment 1

3. Drug interactions: Potential for enhanced CNS depression when combined with alcohol or other CNS depressants

4. Abuse potential: While lower than other opioids, diphenoxylate still has abuse potential at high doses 3

5. Infectious diarrhea: Using antiperistaltic agents in infectious diarrhea (especially with fever or bloody stools) may prolong the infection by reducing pathogen clearance 6

For chronic diarrhea that persists despite appropriate symptomatic treatment, further diagnostic evaluation should be pursued to identify and address the underlying cause rather than continuing symptomatic treatment indefinitely.