Lactulose

Lactulose

Clinical data
Routes of administration	Oral
ATC code	A06AD11 (WHO)
Legal status
Legal status	UK: P (Pharmacy medicines)
Pharmacokinetic data
Bioavailability	Poorly absorbed
Metabolism	100% in colon by enteric bacteria
Elimination half-life	1.7-2 hours
Excretion	rectal
Identifiers
IUPAC name 4-O-(beta)-D-Galactopyranosyl-D-fructofuranose
CAS Number	4618-18-2
PubChem CID	11333
DrugBank	APRD01063
CompTox Dashboard (EPA)	DTXSID5045833
ECHA InfoCard	100.022.752
Chemical and physical data
Formula	C12H22O11
Molar mass	342.296 g/mol g·mol−1

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 is yellow.

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.

It can be also useful for treating children that withhold their bowel movements out of fear.

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.

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®
• Actilax®

References

• 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