What is the indication for lactulose?

From the Guidelines

Lactulose is primarily used to treat constipation and hepatic encephalopathy, with a typical adult dose of 15-30 ml once or twice daily for constipation and higher doses of 30-45 ml three to four times daily for hepatic encephalopathy. For constipation, lactulose works as an osmotic laxative by drawing water into the colon, softening stool and increasing bowel movements 1. The medication typically begins working within 24-48 hours after starting treatment.

Key Points

• Lactulose is used to treat constipation and hepatic encephalopathy, a brain disorder caused by liver disease.
• The typical adult dose for constipation is 15-30 ml once or twice daily, while for hepatic encephalopathy, higher doses of 30-45 ml three to four times daily are often needed.
• Lactulose works by changing the acidity in the intestines, which reduces the absorption of ammonia into the bloodstream, particularly important in liver disease where ammonia builds up and affects brain function.
• Side effects may include bloating, gas, stomach cramps, and diarrhea if the dose is too high.
• Patients should drink plenty of water while taking lactulose and may need to adjust the dose to achieve 2-3 soft bowel movements daily.

Recommendations

• Lactulose is recommended for the treatment of constipation and hepatic encephalopathy, with the dose titrated to achieve 2-3 soft bowel movements daily 1.
• Rifaximin may be added to lactulose for the treatment of hepatic encephalopathy in cases of failed prevention with lactulose alone 1.
• Lactulose may be used to prevent the recurrence of hepatic encephalopathy in patients with cirrhosis, with rifaximin added in cases of failed prevention 1.

From the FDA Drug Label

For the prevention and treatment of portal-systemic encephalopathy, including the stages of hepatic pre-coma and coma. Lactulose is used for the prevention and treatment of:

• Portal-systemic encephalopathy
• Hepatic pre-coma
• Coma 2

From the Research

Uses of Lactulose

• Lactulose is used in the treatment of constipation and hepatic encephalopathy due to its efficacy and good safety profile 3.
• It is a synthetic disaccharide that is not absorbed from the small intestine and is fermented by colonic bacterial flora, producing short-chain fatty acids and gases 3.
• Lactulose may also have a role in the management and prevention of type 2 diabetes via actions on the gut microbiota 4.
• At low doses, lactulose can be used as a prebiotic to stimulate the growth of health-promoting bacteria in the gastrointestinal tract 5.
• It has been shown to enhance the proliferation of health-promoting gut bacteria, increase the production of beneficial metabolites, and inhibit the growth of potentially pathogenic bacteria 5, 6.

Mechanism of Action

• The mechanism of action of lactulose is based on its fermentation by intestinal microbiota, which promotes the growth and activity of lactic acid bacteria in the gut 6, 7.
• Lactulose can increase the abundance of short-chain fatty acid-producing bacteria, such as Lactobacillus and Bifidobacterium, and suppress potentially pathogenic bacteria, such as Escherichia coli 4.
• The effects of lactulose on human microbiota composition are both patient- and dose-dependent 7.

Additional Benefits

• Lactulose may have anti-inflammatory effects, nourish the gut epithelial cells, and provide a protective barrier from microorganism infection 4.
• It may also enhance the absorption of minerals, such as calcium and magnesium, from the gut, which can have important implications for bone health 5.