DIPHENOXYLATE HYDROCHLORIDE WITH ATROPINE SULFATE

DIPHENOXYLATE HYDROCHLORIDE WITH ATROPINE SULFATE
(dye-fen-ox'i-late)
Diphenatol, Lofene, Lomanate, Lomotil, Lonox, Lo-Trol, Low-Quel, Nor-Mil
Classifications: antidiarrheal;
Therapeutic: antidiarrheal
Pregnancy Category: C
Controlled Substance: Schedule V

Availability

2.5 mg tablets; 2.5 mg/5 mL liquid

Action

Diphenoxylate is a synthetic narcotic opiate agonist. Commercially available only with atropine sulfate, added in subtherapeutic doses to discourage deliberate overdosage. Inhibits mucosal receptors responsible for peristaltic reflex, thereby reducing GI motility.

Therapeutic Effect

Reduces GI motility. Has little or no analgesic activity or risk of dependence, except in high doses.

Uses

Adjunct in symptomatic management of diarrhea.

Contraindications

Hypersensitivity to diphenoxylate or atropine; severe dehydration or electrolyte imbalance, advanced liver disease, obstructive jaundice, diarrhea caused by pseudomembranous enterocolitis associated with use of broad-spectrum antibiotics; diarrhea associated with organisms that penetrate intestinal mucosa; diarrhea induced by poisons until toxic material is eliminated from GI tract; glaucoma; children <2 y of age; pregnancy (category C), lactation.

Cautious Use

Advanced hepatic disease, abnormal liver function tests; renal function impairment, MAOI therapy; patients receiving addicting drugs, addiction-prone individuals, or those whose history suggests drug abuse; ulcerative colitis; young children (particularly patients with Down syndrome).

Route & Dosage

Diarrhea
Adult: PO 1–2 tablets or 1–2 teaspoons full (5 mL) 3–4 times/d (each tablet or 5 mL contains 2.5 mg diphenoxylate HCl and 0.025 mg atropine sulfate)
Child (2–12 y): PO 0.3–0.4 mg/kg/d of liquid in divided doses

Administration

Oral

Crush tablet if necessary and give with fluid of patient's choice.
Reduce dosage as soon as initial control of symptoms occurs.
Withhold drug in presence of severe dehydration or electrolyte imbalance until appropriate corrective therapy has been initiated.
Note: Treatment is generally continued for 24–36 h before it is considered ineffective.
Store in tightly covered, light-resistant container, preferably 15°–30° C (59°–86° F), unless otherwise directed by manufacturer.

Adverse Effects (≥1%)

Body as a Whole: Hypersensitivity (pruritus, angioneurotic edema, giant urticaria, rash). CNS: Headache, sedation, drowsiness, dizziness, lethargy, numbness of extremities; restlessness, euphoria, mental depression, weakness, general malaise. CV: Flushing, palpitation, tachycardia. Special Senses: Nystagmus, mydriasis, blurred vision, miosis (toxicity). GI: Nausea, vomiting, anorexia, dry mouth, abdominal discomfort or distension, paralytic ileus, toxic megacolon. Other: Urinary retention, swelling of gums.

Interactions

Drug: mao inhibitors may precipitate hypertensive crisis; alcohol and other cns depressants may enhance CNS effects; also see atropine.

Pharmacokinetics

Absorption: Readily absorbed from GI tract. Onset: 45–60 min. Peak: 2 h. Duration: 3–4 h. Distribution: Distributed into breast milk. Metabolism: Rapidly metabolized to active and inactive metabolites in liver. Elimination: Slowly through bile into feces; small amount in urine. Half-Life: 4.4 h.

Nursing Implications

Assessment & Drug Effects

Assess GI function; report abdominal distention and signs of decreased peristalsis.
Monitor for S&S of dehydration (see Appendix F). It is essential to monitor young children closely; dehydration occurs more rapidly in this age group and may influence variability of response to diphenoxylate and predispose patient to delayed toxic effects.
Monitor frequency and consistency of stools.

Patient & Family Education

Take medication only as directed by physician.
Notify physician if diarrhea persists or if fever, bloody stools, palpitation, or other adverse reactions occur.
Do not drive or engage in other potentially hazardous activities until response to drug is known.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

(164)