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a synthetic disaccharide used as a cathartic and to enhance the excretion of ammonia in treatment of hepatic encephalopathy.


Apo-Lactulose (CA), Constulose, Duphalac (UK), Enulose, Euro-Lac (CA), Generlac, Gen-Lac (CA), GPI-Lactulose (CA), Kristalose, Lactugal (UK), Lactulax (CA), Lemlax (UK), PMS-Lactulose (CA), Ratio-Lactulose (CA), Regulose (UK)

Pharmacologic class: Osmotic

Therapeutic class: Laxative

Pregnancy risk category B


Produces osmotic effect, which increases water content in colon and enhances peristalsis. Breakdown products in colon lead to acidification of colonic contents, softening of feces, and decreased ammonia absorption from colon to systemic circulation. These effects reduce blood ammonia level in portal-system encephalopathy.


Powder (single-use packets): 10 g, 20 g

Syrup: 10 g/15 ml

Indications and dosages


Adults: 10 to 20 g (15 to 30 ml) P.O. daily; may increase to 60 ml daily p.r.n.

Portal-system encephalopathy

Adults: 20 to 30 g (30 to 45 ml) P.O. three or four times daily until two or three soft stools are produced daily. Therapy may continue over long term. Or, 300 ml P.O. with 700 ml of water or normal saline solution. Or, as retention enema by rectal balloon catheter, repeated q 4 to 6 hours.


• Patients requiring low-galactose diet


Use cautiously in:
• diabetes mellitus
• elderly patients
• pregnant or breastfeeding patients
• children.


• Don't give concurrently with other laxatives.
• Dissolve contents of single-use packet in 4 oz of water or juice.
• Dilute syrup with water or fruit juice to mask taste.

Adverse reactions

GI: nausea, vomiting, diarrhea, intestinal cramps, abdominal distention, flatulence

Metabolic: hyperglycemia (in diabetic patients), hypokalemia, hypernatremia


Drug-drug.Anti-infectives: decreased lactulose efficacy

Other laxatives: interference with response to lactulose (in patients with hepatic encephalopathy)

Drug-diagnostic tests.Blood ammonia: 25% to 50% decrease

Glucose: increased level (in diabetic patients)

Potassium: decreased level

Sodium: increased level

Patient monitoring

• Watch for adverse GI reactions.
• Check stool consistency and frequency.
• Monitor electrolyte levels, especially in elderly patients.
• Check blood glucose level in diabetic patients.

Patient teaching

• Instruct patient to dissolve contents of single-use packet in 4 oz of water or juice.
• Suggest that patient dilute syrup with water or juice to mask taste.
• Tell patient drug may cause flatulence and intestinal cramps at first, but these symptoms usually subside.
• Inform patient that excessive use may cause diarrhea and excessive fluid loss.
• Encourage patient to drink adequate fluids and to report signs and symptoms of dehydration.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs and tests mentioned above.


A synthetic disaccharide used to treat hepatic encephalopathy and chronic constipation.


/lac·tu·lose/ (lak´tu-lōs) a synthetic disaccharide used as a laxative and to enhance excretion or formation of ammonia in the treatment of hepatic encephalopathy.


a nonabsorbable synthetic disaccharide, 4-0-beta-d-galactopyranosyl-D-fructose, C12H22O11. It is hydrolyzed in the colon by bacteria primarily to lactic acid and small amounts of formic and acetic acids, which results in increased osmotic pressure and acidification of the colonic contents. It is used as a cathartic in chronic constipation. Because the acidification causes ammonia to be removed from the blood to form ammonium ion, it is also used in the treatment of hepatic coma. Its ability to increase fecal water content, however, may also cause diarrhea.


A synthetic disaccharide used to treat hepatic encephalopathy, which is administered by mouth, acting as a laxative; lactulose reduces intraluminal NH3 which, via the extracellular fluid, reduces NH3 in the blood.


A synthetic disaccharide used to treat hepatic encephalopathy and chronic constipation.


A disaccharide sugar that acts as a gentle but effective LAXATIVE. It is not absorbed or broken down but remains intact until it reaches the colon where it is split by bacteria and helps to retain water, thereby softening the stools. Brand names are Duphalac, Lactugal and Regulose.


a synthetic disaccharide used as a cathartic and to enhance the excretion of ammonia in the treatment of hepatic encephalopathy.
References in periodicals archive ?
A report by Fenves et al (3) described the case of 5 women who lapsed into coma and died in spite of treatment with lactulose, antibiotics, nutritional repletion, and supportive care.
Lactulose, a nonabsorbable disaccharide that alters colonic pH and bowel frequency, has been the mainstay of therapy for hepatic encephalopathy, although the laxative effect of lactulose can be a problem for some patients.
Comparison of polyethylene glycol 3350 and lactulose for treatment of chronic constipation in children.
Luckily, I have a big bottle of Lactulose back in the room," he said.
With the exception of lactulose and tegaserod, these products are available over the counter.
Scientists at Finland's VTT Biotechnology Institute have shown that combining lactulose (a prebiotic lactose derivative) and a probiotic strain (L.
Then Levitt fed the volunteers a hefty amount of pinto beans and lactulose, a poorly absorbed sugar, "to enhance flatus output.
Osmotic laxatives like Lactulose work by drawing water into the bowel, so softening the stools.
The new prescription stool softener Miralax and the older softener lactulose are good medications.
Disaccharides, including lactulose and cellobiose, pass through the intercellular functional complexes and extrusion zones at the vinous tips, reflecting the permeability of large molecules (0.
Knowing that lactulose (Cephulac/Chronulac) is more expensive ($25-30 per pint cost to pharmacy) than sorbitol ($4-5 per pint), used in the same dosage of 15-60 ml/day, which is just as effective as lactulose.