Article: Lactulose

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. weight	342.296 g/mol
Pharmacokinetic data
Bioavailability	Poorly absorbed
Metabolism	100% in colon by enteric bacteria
Half life	1.7-2 hours
Excretion	rectal
Therapeutic considerations
Pregnancy cat.	?
Legal status	OTC (UK)
Routes	oral

Lactulose is a synthetic sugar used in the treatment of constipation and hepatic encephalopathy, a complication of liver disease. It consists of the monosaccharides fructose and galactose and has a yellow color.

Constipation

In the treatment of chronic constipation, its metabolites draw water into the bowel, causing a cathartic effect through osmotic action.

It can be especially useful for negating the constipating effects of opiates and opioids. The United States is the only country in the world that requires a prescription for purchase.

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 also 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.

Side effects

Side effects include diarrhea and resultant dehydration and high sodium levels. In rare cases or in excess amounts, lactulose can cause stomach pain, gas, vomiting, or diarrhea.

Brand names

• Generlac®
• Cephulac®
• Cholac®
• Constilac®
• Enulose®
• Acilac®
• Heptalac®