Lactulose

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Lactulose
Systematic (IUPAC) name
4-O-(beta)-D-Galactopyranosyl-D-fructofuranose
Identifiers
CAS number 4618-18-2
ATC code A06AD11
PubChem 11333
DrugBank APRD01063
Chemical data
Formula C12H22O11 
Mol. mass 342.296 g/mol
Pharmacokinetic data
Bioavailability Poorly absorbed
Metabolism 100% in colon by enteric bacteria
Half life 1.7-2 hours
Excretion Fecal
Therapeutic considerations
Pregnancy cat.

B(US)
Legal status

P(UK)
Routes Oral

Lactulose is a synthetic sugar used in the treatment of constipation and hepatic encephalopathy, a complication of liver disease. It is a disaccharide (double-sugar) formed from one molecule each of the simple sugars (monosaccharides) fructose and galactose. The commercial syrup used for treatment of constipation is dyed yellow-orange. It is produced commercially by isomerization of lactose.

Contents

[edit] Constipation

In the treatment of chronic constipation, the metabolites of lactulose draw water into the bowel, causing a cathartic effect through osmotic action. Unlike other laxatives that are recommended for temporary relief, lactulose can be taken daily for decades, and is safe for people of all ages, except for those who are galactose intolerant or are suffering from renal insufficiency (common to all osmotic laxatives). Dosage may have to be adjusted over time to produce the desired effect.

It can be especially useful for negating the constipating effects of opiates and opioids, and for treating children who withhold their bowel movements out of fear.[1]

Lactulose has an overly sweet taste that can be completely masked by mixing it with fruit juice or desserts. It can take 24 to 48 hours to work, but generally produces results within 4 hours if taken on a daily basis. It is best taken at breakfast along with a bowl of bran cereal.

[edit] Hepatic encephalopathy

In treating hepatic encephalopathy, lactulose helps "draw out" ammonia (NH3) from the body. The effectiveness of lactulose is somewhat controversial, and whether or not its effects are through ammonia is controversial as well. Lactulose is metabolized in the colon by bacterial flora to short chain fatty acids, acidifying the colonic contents. This favors the formation of the nonabsorbable NH4+ from NH3, trapping NH3 in the colon and effectively reducing plasma NH3 concentrations.

[edit] Side effects

Common side effects are abdominal cramping, gas, borborygmus and flatulence. Less common side effects are nausea and vomiting. Excessively high dosage can cause explosive and uncontrollable diarrhea.

In sensitive individuals, such as the elderly or people with reduced kidney function, excess dosage can result in dehydration and high sodium levels.

[edit] Brand names

  • Generlac
  • Cephulac
  • Cholac
  • Constilac
  • Enulose
  • Acilac
  • Heptalac
  • Actilax
  • Duphalac
  • Kristalose
  • Apo-Lactulose

[edit] References

  1. ^ Lactulose at The Medical Dictionary
  • Medline Plus
  • Deglin, J. H., & Vallerand A. H. (2003). Lactulose. In Davis's drug guide for nurses (9th ed.) (pp. 589-590). Philadelphia:F. A. Davis.
  • Actilax / Lactulose Virtual Cancer Centre
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