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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 ?
27) Probiotics had no impact on the overall mortality compared to either lactulose or no treatment/placebo.
d) ammonia-reducing agents such as lactulose, carnitine, and neomycin
Regarding the efficacy, rifaximin plus lactulose was effective in 45(74%) patients while lactulose alone was effective in 32(53%) patients with hepatic encephalopathy.
The patients were divided into 2 groups by randomization: (1) an L group that was treated with gelatinous lactulose (N = 48) and (2) a control group (C group) that did not receive gelatinous lactulose (N = 52) (Figure 1).
Although recent research has found lactulose improves cognitive function and quality of life in patients with hepatic encephalopathy (Prasad et al.
The study looked at the charts of 198 patients who underwent lactulose hydrogen breath testing (LHBT) to determine the presence of SIBO, and found that any current alcohol consumption was significantly associated with the presence of SIBO.
Q I AM still constipated, despite using lactulose and movicol.
The panelists supporting approval emphasized that the drug's labeling should clearly inform prescribes that most of the patients (91%) who participated in the study submitted for approval were also being treated with lactulose, a drug approved in the 1970s for the indication, and that most had Child-Pugh class A or B cirrhosis.
Lactulose, sorbitol, Milk of Magnesia, and magnesium citrate are all osmotic laxatives that work like polyethylene glycol.
After ingesting lactulose solution, the patient produces breath samples every 20 minutes over a three-hour period.
An intestinal permeability test was done using a standard solution containing lactulose (250 mg/mL; Lactulona[R], Luitpold Produtos Farmaceuticos Ltda, S.
Comparison of polyethylene glycol 3350 and lactulose for treatment of chronic constipation in children.