Lomotil Dosing Recommendations
For adults, the recommended initial dose of Lomotil (diphenoxylate-atropine) is two tablets (2.5 mg diphenoxylate per tablet) four times daily (total 20 mg/day), which can be reduced to as little as 5 mg daily once control is achieved. 1
Adult Dosing
- Initial dose: 2 tablets (5 mg diphenoxylate) four times daily for a total of 20 mg per day 1
- Maintenance dose: After initial control is achieved, reduce to meet individual requirements—often as little as 2 tablets (5 mg) daily 1
- Duration considerations: Clinical improvement in acute diarrhea should occur within 48 hours; if chronic diarrhea does not improve after 10 days at maximum dose (20 mg/day), further administration is unlikely to help 1
Pediatric Dosing
- Contraindicated in children under 2 years of age due to risk of serious toxicity including respiratory depression 1, 2
- Children under 13 years: Use only oral solution, not tablets 1
- Special caution required in young children, with careful attention to nutritional status and hydration 1
Critical Safety Considerations
Lomotil is generally NOT the preferred first-line agent for diarrhea management. Loperamide is recommended as first-line treatment by the American Gastroenterological Association because it is more effective with fewer central nervous system effects than Lomotil 3, 4. Diphenoxylate-atropine requires a prescription, is less effective than loperamide, and has more central and peripheral side effects 4.
Important Contraindications and Warnings:
- Never use in severe dysentery with high fever or bloody stools 3
- Avoid in suspected infectious diarrhea caused by invasive organisms like Shigella, Salmonella, or STEC 3
- Pediatric toxicity risk: Respiratory depression is the most threatening reaction in children, occurring 13-24 hours post-ingestion due to accumulation of the active metabolite difenoxine 5
- Abuse potential: Diphenoxylate is an opioid with documented cases of dependence, requiring regulatory controls 6
Clinical Context for Use
Lomotil is listed as an alternative option for loperamide-refractory therapy-associated diarrhea in cancer patients, but only after exclusion of infectious causes and with careful risk-benefit assessment in neutropenic patients 7. In this setting, it is considered a third-line option after loperamide and octreotide have been tried 7.
Do not exceed the recommended 20 mg daily dosage to avoid serious adverse effects including respiratory depression, particularly the delayed effects that can occur up to 24 hours after ingestion 1, 5.