Action

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

Availability

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

➣ Diarrhea

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

Contraindications

• 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

Precautions

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).

Administration

See 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.

See 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

Interactions

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

See 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.