Lactulose

A to Z Drug Facts

(LAK-tyoo-lohs)

Cephulac, Cholac, Chronulac, Constilac, Constulose, Duphalac, Enulose,  Acilac, Gen-Lac, Lactulax, Laxilose, PMS-Lactulose

Class: Laxative

 Action Produces increased osmotic pressure within colon and acidifies its contents, resulting in increased stool water content and stool softening. Causes migration of ammonia from blood into colon where it is converted to ammonium ion and expelled through laxative action.

 Indications Treatment of constipation; prevention and treatment of portal-systemic encephalopathy including stages of hepatic precoma and coma.

 Contraindications Use in patients who require low-galactose diet.

 Route/Dosage

Constipation (Chronulac, Constilac, Duphalac)

ADULTS: PO 15 to 30 mL (10 to 20 g lactulose) daily; may increase to 60 mL/day.

Portal-Systemic Encephalopathy (Cephulac, Cholac, Enulose)

ADULTS: PO 30 to 45 mL tid to qid. Adjust dosage to produce 2 to 3 soft stools/day. Hourly doses of 30 to 45 mL may be used for rapid laxation initially; once achieved, reduce to recommended daily dose. PR 300 mL with 700 mL water or physiologic saline solution via rectal balloon catheter; retain for 30 to 60 min. May repeat q 4 to 6 hr. OLDER CHILDREN AND ADOLESCENTS: PO 40 to 90 mL/day in divided doses to produce 2 to 3 soft stools/day. INFANTS: PO 2.5 to 10 mL/day in divided doses to produce 2 to 3 soft stools/day.

 Interactions

Neomycin, other anti-infectives: May interfere with desired degradation of lactulose and prevent acidification of colonic contents. Nonabsorbable antacids: May inhibit colonic acidification.

 Lab Test Interferences None well documented.

 Adverse Reactions

GI: Gaseous distention with flatulence or belching, abdominal discomfort and cramping; diarrhea; nausea; vomiting.

 Precautions

Pregnancy: Category B. Lactation: Undetermined. Children: Safety and efficacy not established. Administer with caution. Infants receiving lactulose may develop hyponatremia and dehydration. Elderly or debilitated patients: With long-term therapy (> 6 mo) at increased risk of dehydration and electrolyte imbalance. Concomitant laxative use: Do not use other laxatives, especially during initial phase of therapy. Resultant loose stools may falsely suggest adequate lactulose dosage. Diabetic patients: Lactulose syrup contains galactose and lactose. Use drug with caution. Electrocautery procedures: Although not reported for lactulose, theoretical hazard exists for patients being treated with lactulose who may undergo electrocautery procedures during proctoscopy or colonoscopy. Accumulation of hydrogen gas in presence of electrical spark may result in explosion. Therefore patients should have thorough bowel cleansing with nonfermentable solution before undergoing such procedures.

 Administration/Storage

• Mix with fruit juice, water or milk to make more palatable.
• Administer with full glass of fruit juice, water or milk.
• May administer to adults during impending coma or coma stage of portalsystemic encephalopathy as retention enema via rectal balloon catheter when danger of aspiration exists or when endoscopic or intubation procedures interfere with oral administration. Do not use cleansing enemas containing soapsuds or other alkaline agents. If enema is inadvertently evacuated too promptly, may repeat it immediately.
• Store at room temperature; do not freeze.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Assess for abdominal distention and discomfort.
• Evaluate bowel sounds and bowel function.
• Assess consistency and frequency of stool produced.
• Do not use other laxatives.
• Encourage fluid intake.
• Keep patient clean and dry. Assess skin integrity frequently.
• Monitor electrolyte balance and liver function.
• Monitor I&O.
• In elderly or debilitated patients who receive lactulose > 6 mo, measure serum electrolytes (potassium, chloride) and carbon dioxide periodically.
• Monitor mental status (eg, orientation, lethargy, irritability) in portal-systemic encephalopathy patients.
• If concomitant oral anti-infectives are given, monitor patient closely.
• If diarrhea, rectal bleeding, nausea, vomiting, abdominal cramps or distention occurs, discontinue medication and notify physician.

 Patient/Family Education

• Advise patient that drug can be mixed with fruit juice, water or milk to make it more palatable.
• Inform patient that drug may cause belching, flatulence or abdominal cramps. Instruct patient to notify physician if these symptoms become bothersome or if diarrhea occurs.
• Instruct patient not to take other laxatives while receiving lactulose therapy.
• Encourage patient to increase dietary fiber and fluid intake and participate in regular exercise.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts