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Cephulac: Full Drug Profile

Medically reviewed by Min Clinic Staff | Updated: January 2026

Cephulac - General Information

A synthetic disaccharide used in the treatment of constipation and hepatic encephalopathy. It has also been used in the diagnosis of gastrointestinal disorders. (From Martindale, The Extra Pharmacopoeia, 30th ed, p887)

 

Pharmacology of Cephulac

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.

 

Cephulac for patients

 

Cephulac Interactions

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.

 

Cephulac Contraindications

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.

 

Additional information about Cephulac

Cephulac Indication

For the treatment of constipation and hepatic encephalopathy.

Mechanism Of Action
Cephulac 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.
Food Interactions
Take without regard to meals. Drink liberally.
Generic Name
Lactulose
Drug Category
Gastrointestinal Agents
Drug Type
Small Molecule; Approved
Other Brand Names containing Lactulose
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;
Absorption
Poorly absorbed from the gastrointestinal tract as no human enzyme that is capable of hydrolysis of this disaccharide is present in human gastrointestinal tissue.
Toxicity (Overdose)
LD50=18.2 g/kg (oral, rat). Side effects include diarrhea and resultant dehydration.
Biotransformation
Lactulose is completely metabolized in the colon by enteric bacteria, and no lactulose is excreted in the feces.
Half Life
1.7-2 hours
Dosage Forms of Cephulac
Liquid Oral
Chemical IUPAC Name
(2S,3R,4S,5R,6R)-2-[(2R,3S,4S,5R)-4,5-dihydroxy-2,5-bis(hydroxymethyl)oxolan-3-yl]oxy-6-(hydroxymethyl)oxane-3,4,5-triol
Chemical Formula
C12H22O11
Organisms Affected
Humans and other mammals