Atropine and diphenoxylate

Generic name:

Atropine and diphenoxylate

Drug class:

Antidiarrheal combination: anticholinergic and opioid

Dosage form:

Tablet; Oral solution

Route of administration:

Oral

Dose:

• Adults: Tablets: 2 tablets (diphenoxylate 5 mg/atropine 0.05 mg) initially, then 1–2 tablets after each unformed stool; do not exceed 8 tablets (20 mg diphenoxylate) per day. Oral solution: 5 mL (diphenoxylate 2.5 mg/atropine 0.025 mg) 1–2 teaspoonfuls initially, then 5 mL after each loose stool; do not exceed 40 mL per day.
• Children (2–13 years): Varies by indication; consult label.
• Children <2 years: Contraindicated.

Mechanism of action:

Diphenoxylate is an opioid agonist at GI mu-receptors, slowing intestinal motility and increasing water absorption. Atropine is an anticholinergic agent that reduces gut secretions and motility to discourage abuse.

Drug usage cases:

• Acute nonspecific diarrhea
• Chronic diarrhea
• Traveler’s diarrhea (off-label)
• Irritable bowel syndrome with diarrhea (off-label)

Drug contra indications:

• Hypersensitivity to diphenoxylate, atropine, or opioids
• Pseudomembranous colitis (Clostridioides difficile infection)
• Diarrhea with fever or bloody stools
• Obstructive jaundice
• Paralytic ileus or GI obstruction
• Severe hepatic or renal impairment
• Children <2 years of age

Side effects:

• Dry mouth
• Blurred vision
• Photophobia
• Tachycardia
• Urinary retention
• Drowsiness
• Dizziness
• Nausea and vomiting
• Abdominal pain
• Constipation
• Hypotension
• Respiratory depression (rare)
• Paralytic ileus
• Toxic megacolon
• Anticholinergic toxicity: hyperthermia, confusion, delirium
• Potential for opioid dependence

Warnings:

• Risk of opioid dependence and abuse
• Monitor for anticholinergic toxicity, especially in elderly
• Avoid in dehydrated patients
• May mask symptoms of underlying conditions (e.g., infections)
• Not for pediatric use under 2 years
• Caution in hepatic or renal impairment
• Discontinue if no improvement within 48 hours
• Avoid concomitant CNS depressants

Use during pregnancy or breastfeeding:

Pregnancy category C. Animal studies show potential fetal risk; use only if benefit justifies risk. Diphenoxylate and atropine are excreted in breast milk and may cause respiratory depression or anticholinergic effects in nursing infants; use with caution or consider alternative therapy.