diphenoxylate hydrochloride and atropine sulfate

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Related to diphenoxylate hydrochloride and atropine sulfate: Lonox

diphenoxylate hydrochloride and atropine sulfate (co-phenotrope (UK))

Lomotil, Lonox

Pharmacologic class: Anticholinergic, meperidine congener

Therapeutic class: Antidiarrheal

Controlled substance schedule V

Pregnancy risk category C


Acts on smooth muscle of GI tract by decreasing peristalsis, which inhibits motility. (Small amount of atropine is added to reduce abuse potential.)


Liquid: 2.5 mg diphenoxylate and 0.025 mg atropine/5 ml

Tablets: 2.5 mg diphenoxylate and 0.025 mg atropine

Indications and dosages


Adults: Initially, 5 mg P.O. three to four times daily, then 5 mg/day as needed (not to exceed 20 mg/day). Decrease dosage when desired response occurs.

Children: Initially, 0.3 to 0.4 mg/kg P.O. (liquid only) daily in four divided doses. Decrease dosage when desired response occurs.

Dosage adjustment

• Elderly patients


• Hypersensitivity to drug
• Obstructive jaundice
• Diarrhea associated with pseudomembranous colitis or enterotoxinproducing bacteria
• Angle-closure glaucoma
• Concurrent MAO inhibitor use
• Children younger than age 2


Use cautiously in:
• inflammatory bowel disease; prostatic hypertrophy; severe hepatic disease (use with extreme caution)
• concurrent use of drugs that cause physical dependence; history of physical drug dependence
• elderly patients
• pregnant or breastfeeding patients
• children (safety not established in children younger than age 12).


Don't confuse brand name Lomotil with Lamictal (an anticonvulsant). Serious errors have been reported.
• Withhold drug if patient has severe fluid or electrolyte imbalance.
• Administer with food if GI upset occurs.

Don't give within 14 days of MAO inhibitors.

Adverse reactions

CNS: dizziness, confusion, drowsiness, headache, insomnia, nervousness

CV: tachycardia

EENT: blurred vision, dry eyes

GI: nausea, vomiting, constipation, epigastric distress, ileus, dry mouth

GU: urinary retention

Skin: flushing


Drug-drug.CNS depressants (including antihistamines, sedative-hypnotics, opioids): increased CNS depression

Anticholinergic-like drugs (including tricyclic antidepressants, disopyramide): increased anticholinergic effects

MAO inhibitors: hypertensive crisis

Drug-diagnostic tests.Amylase: increased level

Drug-herbs.Angel's trumpet, jimsonweed, scopolia: increased anticholinergic effects

Drug-behaviors.Alcohol use: increased CNS depression

Patient monitoring

Assess for and report abdominal distention and signs or symptoms of decreased peristalsis.
• Watch for signs and symptoms of dehydration.
• Assess frequency and consistency of bowel movements.

Patient teaching

• Instruct patient to report persistent diarrhea.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Tell patient that prolonged use may lead to dependence.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.