Ursodiol for Veterinary Use

Therapeutic Class: Bile Acid

Species: Dogs and cats

May Be Prescribed For: Cholestatic liver disease of dogs and cats.

Ursodiol, also known as ursodeoxycholic acid, is a hydrophilic bile-acid that has been used successfully in treatment of cholestatic liver-diseases of humans including chronic hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, intrahepatic cholestasis of pregnancy, non-alcoholic fatty liver disease, TPN-induced cholestasis, some pediatric cholestatic liver diseases, and graft/host liver transplant reactions. Ursodiol has a number of hepatoprotective properties including immunomodulatory, cytoprotective and membrane stabilizing effects on hepatic cells. It expands the bile acid pool by increasing flow and displaces hepatotoxic, hydrophobic bile acids. It suppresses the synthesis, secretion and intestinal absorption of cholesterol. Ursodiol is well-absorbed through oral administration.

Ursodiol is now used in a variety hepatobiliary conditions in small animals. Its use is better established in dogs although it also has been reported on in cats. In dogs, ursodiol is used in chronic hepatitis, some forms of acute hepatic failure or toxic injury, some congenital abnormalities including primary portal vein hypoplasia, and juvenile fibrosing liver disease.

There is less information on the use of ursodiol in cats, but it may be used in cases of chronic hepatitis and congenital portosystemic shunts.

Ursodiol should be given with food. Efficacy may be monitored by using liver enzymes, ultrasound, or other liver function tests.

Ursodiol generally is well tolerated. Vomiting and diarrhea rarely occur. Side effects in humans include diarrhea and other GI symptoms.

• Ursodiol may be contraindicated in patients with biliary obstruction, fistula, and other complications associated with gallstones or pancreatitis.

• Some patients with chronic liver-disease may have increased difficulty with bile acid metabolism.

• Ursodiol should not be used in rabbits or other hindgut fermenters.

• Ursodiol has been investigated in pregnant women with intrahepatic cholestasis of pregnancy and has been found to improve fetal prognosis. Similar work has not been done in animals. It is not known if ursodiol is excreted in breast milk.

Concurrent antacid use may decrease the effectiveness of ursodiol.

The most likely occurrence with overdose is an increase in severity of GI signs, particularly diarrhea. Gastric-emptying, activated charcoal, and oral administration of an aluminum-containing antacid may be indicated.