Ursodiol (ursodeoxycholic acid)

What is this medication for?

• Adjunctive therapy of chronic hepatobiliary disease — cholestasis, cholangitis/cholangiohepatitis, chronic (active) hepatitis, copper-associated hepatopathy, fibrosis/cirrhosis
• Medical management of cholesterol-containing gallstones

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Taurine depletion (Theoretical concern with chronic feline use)

Worth a phone call to your veterinarian

• Generally well tolerated (Limited use but no liver damage signal)
• Diarrhea/occasional stomach/intestinal effects (Rare (human))
• Lithocholic acid metabolite liver damage (Humans unable to sulfate it; veterinary significance unclear)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Trouble breathing, collapse, seizures, severe vomiting or diarrhea, facial swelling, or pale gums

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Rabbits/hindgut fermenters (converts to toxic lithocholic acid); bile-acid hypersensitivity
• has or has had: Gallstone complications (obstruction, fistula, cholecystitis, pancreatitis, cholangitis) — weigh risk/benefit; some liver patients have impaired bile-acid metabolism

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Aluminum antacids
  • Cholestyramine resin
  • Taurine

Storage and handling

Room temperature. Human capsules; cats often get a fraction sprinkled on food.

Good to know

• Mechanism trio: ① ↑ bile flow (choleretic), ② ↓ hepatic cholesterol synthesis/secretion + intestinal absorption (desaturates bile → dissolves cholesterol stones), ③ displaces toxic hydrophobic bile acids from the hepatocyte detergent injury — the last is why it helps cholestatic liver disease generally.
• Adjunct, not a monotherapy: pair with immunosuppression in chronic active hepatitis and address copper (chelation/diet) in copper hepatopathy.
• Will not touch radiopaque/calcified or pigment stones — imaging before committing to medical dissolution.