Ursodeoxycholic acid (UDCA), also known as ursodiol, is a natural bile acid used to dissolve gallstones and treat certain liver diseases, particularly primary biliary cirrhosis. It’s a hydrophilic bile acid, meaning it is water-soluble and less toxic than other bile acids. UDCA works by replacing more toxic bile acids in the bile acid pool, thus protecting liver cells and promoting bile flow.
Here’s a more detailed explanation:
What it is:
UDCA is a secondary bile acid produced by intestinal bacteria from primary bile acids. It’s a naturally occurring compound found in small quantities in human bile.
How it works:
UDCA alters the composition of bile by decreasing the levels of toxic bile acids and increasing the proportion of hydrophilic, non-toxic bile acids. This helps protect liver cells from damage caused by bile acids, especially in conditions like primary biliary cirrhosis where the bile ducts are damaged.
Uses:
Dissolving gallstones: UDCA can be used to dissolve cholesterol gallstones in patients who are not able to or do not want to have gallbladder surgery.
Treating liver diseases: It’s used to treat primary biliary cirrhosis, a chronic liver disease that damages the bile ducts, and other cholestatic liver diseases.
Mechanism of action:
UDCA has multiple mechanisms of action, including:
Cytoprotection: Protecting liver cells from damage caused by bile acids.
Choleretic effect: Stimulating bile production and flow, which helps to clear toxic bile acids.
Immunomodulation: Modulating the immune system to reduce inflammation and damage in the liver.
Clinical applications:
UDCA is used in a variety of liver diseases, including:
Primary biliary cirrhosis (PBC): UDCA is the only drug approved by the FDA for PBC and is considered the standard treatment for this condition.
Primary sclerosing cholangitis (PSC): While its long-term effects in PSC are not fully established, UDCA can help improve liver function tests and may be beneficial for some patients.
Cholestatic liver diseases in children: UDCA may be used in children with cholestatic liver diseases, such as biliary atresia and cystic fibrosis-related liver disease.
Other potential uses:
UDCA is being investigated for other liver conditions, such as non-alcoholic fatty liver disease (NAFLD) and graft-versus-host disease.
Side effects:
UDCA is generally well-tolerated, but rare side effects can include mild liver enzyme elevations, jaundice, and worsening of liver disease in some patients with pre-existing cirrhosis.