Lactulose
Pronouncation: (LAK-tyoo-lohs)Class: Hyperosmotic agent
Trade Names:
Cephulac
- Solution 10 g lactulose/15 mL (less than 1.6 g galactose, less than 1.2 g galactose, and up to 1.2 g of other sugars)
Trade Names:
Chronulac
- Solution 10 g lactulose/15 mL (less than 1.6 g galactose, less than 1.2 g galactose, and up to 1.2 g of other sugars)
Trade Names:
Constilac
- Solution 10 g lactulose/15 mL (less than 1.6 g galactose, less than 1.2 g galactose, and up to 1.2 g of other sugars)
Trade Names:
Constulose
- Solution 10 g lactulose/15mL (less than 1.6 g galactose, less than 1.2ߙg galactose, and up to 1.2 g of other sugars)
Trade Names:
Duphalac
- Solution 10 g lactulose/15 mL (less than 1.6 g galactose, less than 1.2 g galactose up to 1.2 g of other sugars)
Trade Names:
Enulose
- Solution 10 g lactulose per 15 mL (less than 1.6 g galactose, less than 1.2 g galactose, and up to 1.2 g of other sugars)
Laxilose (Canada)
PMS-Lactulose (Canada)
ratio-Lactulose (Canada)
Pharmacology
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Feedback for Lactulose
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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.
Pharmacokinetics
Absorption
Poorly absorbed from the GI tract when given PO and PR (no enzyme capable of hydrolysis of lactulose is present in GI tissue).
Metabolism
In the colon, lactulose is broken down primarily to lactic acid. Metabolized in the colon by bacteria.
Elimination
Less than 3% is excreted in the urine. Doses reach the colon virtually unchanged.
Onset
24 to 48 h.
Indications and Usage
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.
Dosage and Administration
Constipation (Chronulac, Constilac, Duphalac)Adults
PO 15 to 30 mL (10 to 20 g lactulose) daily; may increase to 60ߙmL/day.
Portal-Systemic Encephalopathy (Cephulac, Cholac, Enulose)Adults
PO 30 to 45 mL 3 to 4 times daily. 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 60ߙmin. May repeat every 4 to 6 h.
Older Children and AdolescentsPO 40 to 90 mL/day in divided doses to produce 2 to 3 soft stools/day.
InfantsPO 2.5 to 10 mL/day in divided doses to produce 2 to 3 soft stools/day.
General Advice
Mix with fruit juice, water, or milk to make oral solution more palatable.
Storage/Stability
Store at room temperature (below 86°F). Do not freeze.
Drug Interactions
Neomycin, other anti-infectivesMay interfere with desired degradation of lactulose and prevent acidification of colonic contents.
Nonabsorbable antacidsMay inhibit colonic acidification.
Laboratory Test Interactions
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
With long-term therapy (more than 6ߙmo) 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.
Debilitated patients
With long-term therapy (more than 6ߙmo) at increased risk of dehydration and electrolyte imbalance.
Diabetic patients
Lactulose syrup contains galactose and lactose. Use 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.
Overdosage
Symptoms
Diarrhea, abdominal cramps.
Patient Information
- 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 health care provider 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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More Lactulose resources:
Lactulose - Includes detailed dosage instructions.
Constipation -- Chronic, Hepatic Encephalopathy, Constipation -- Acute
