Brands, Medical Use, Clinical Data
Brands / Synonyms
Acilac; Bifiteral; Cephulac; Cholac; Chronulac; Constilac; Constulose; D-Lactulose; Duphalac; Enulose; Evalose; Fructofuranose; Generlac; Heptalac; Isolactose; Kristalose; Lactulosa [INN-Spanish]; Lactulosa [Spanish]; Lactulose [USAN:BAN:INN:JAN]; Lactulose, ~98%; Lactulosum [INN-Latin]; Lactulosum [Latin]; Laevolac; Lattulosio [Italian]; Laxilose; Portalac
For the treatment of constipation and hepatic encephalopathy.
Therapeutically, lactulose has laxative and ammonia-detoxifying actions. In treating constipation lactulose metabolites draw water into the bowel, causing a cathartic effect through osmotic action.
Mechanism of Action
Lactulose is a synthetic sugar used in the treatment of constipation and liver disease. It consists of the monosaccharides fructose and galactose. In the colon, lactulose is broken down primarily to lactic acid, and also to small amounts of formic and acetic acids, by the action of via evolved-beta galactosidase from colonic bacteria, which results in an increase in osmotic pressure and slight acidification of the colonic contents. This in turn causes an increase in stool water content and softens the stool. In treating heptic diseases (hepatic encephalopathy) it is thought that lactulose draws out ammonia from the body in the same way that it draws out water into the colon.
Poorly absorbed from the gastrointestinal tract as no human enzyme that is capable of hydrolysis of this disaccharide is present in human gastrointestinal tissue.
LD50=18.2 g/kg (oral, rat). Side effects include diarrhea and resultant dehydration.
Biotrnasformation / Drug Metabolism
Lactulose is completely metabolized in the colon by enteric bacteria, and no lactulose is excreted in the feces.
Since KRISTALOSE™ (Lactulose) for Oral Solution contains galactose (less than 0.3 g/10 g as a total sum with
lactose), it is contraindicated in patients who require a low galactose diet.
Results of preliminary studies in humans and rats suggest that nonabsorbable antacids given concurrently with
lactulose may inhibit the desired lactulose-induced drop in colonic pH. Therefore, a possible lack of desired effect
of treatment should be taken into consideration before such drugs are given concomitantly with lactulose.