Ursodiol
Ursodeoxycholic acid
Also known as: Actigall · URSO 250 · URSO Forte · acidum ursodeoxycholicum · UDCA · ursodesoxycholic acid
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Adjunctive treatment of chronic hepatitis | 5-15 mg/kg PO divided q12h | PO | q12h | — | 🌎 NA |
| Cholestatic liver disease, cholangitis/cholangiohepatitis, chronic hepatitis, and copper-associated hepatopathy | 10-15 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
| Chronic active hepatitis, fibrosis and cirrhosis | 11-15.4 mg/kg PO either once daily or divided twice daily | PO | q12h-q24h | — | 🌎 NA |
- Adjunctive treatment of chronic hepatitis: With immunosuppressive therapy. Note: Use of this drug at this dose is preliminary, but promising.
- Cholestatic liver disease, cholangitis/cholangiohepatitis, chronic hepatitis, and copper-associated hepatopathy: Safe and potentially beneficial.
- Chronic active hepatitis, fibrosis and cirrhosis: May use as primary or adjunctive therapy.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Cholestatic liver disease, cholangitis/cholangiohepatitis, chronic hepatitis, and copper-associated hepatopathy | 10-15 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
| Chronic active hepatitis, fibrosis, and cirrhosis | 11-15.4 mg/kg PO either once daily or divided twice daily | PO | q12h-q24h | — | 🌎 NA |
| Adjunctive treatment of chronic hepatitis | 10 mg/kg/day PO | PO | q24h | — | 🌎 NA |
- Cholestatic liver disease, cholangitis/cholangiohepatitis, chronic hepatitis, and copper-associated hepatopathy: Safe and potentially beneficial.
- Chronic active hepatitis, fibrosis, and cirrhosis: May use as primary or adjunctive therapy. Cats usually get 1/6th of a capsule mixed with a small amount of food. Cats may still eat their food even if drug is sprinkled on top.
Birds
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Adjunctive treatment of liver disease | 10-15 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Ursodiol is a naturally occurring, hydrophilic bile acid used primarily as an adjunctive treatment for hepatobiliary disease in dogs and cats.
Clinical Highlights:
- Hepatoprotective: It is highly beneficial in chronic liver diseases, particularly where cholestasis (bile toxicity) plays a role, such as cholangitis, cholangiohepatitis, and copper-associated hepatopathy.
- Gallstone Dissolution: It can be used for the medical management of cholesterol-containing gallstones (radiolucent stones).
- Immunomodulatory: It may help slow the progression of inflammatory hepatic disorders, including autoimmune hepatitis.
Clinical Pearl: Unlike hydrophobic bile acids which are toxic to cell membranes, ursodiol is a cytoprotective hydrophilic bile acid. It shifts the bile acid pool to a less toxic profile, reducing hepatocyte apoptosis and oxidative stress.
Mechanism of action
Ursodiol exerts its effects through multiple hepatoprotective and choleretic pathways:
- Cholesterol Reduction: Suppresses hepatic synthesis and secretion of cholesterol and decreases intestinal absorption of cholesterol.
- Gallstone Solubilization: By reducing cholesterol saturation in the bile, it allows the solubilization of cholesterol-containing gallstones.
- Choleretic Effect: Increases bile flow, which helps flush toxic bile acids from the liver.
- Cytoprotection: Reduces the hepatocyte toxic effects of endogenous hydrophobic bile salts (e.g., lithocholate, deoxycholate) by decreasing their detergent action on cell membranes, thereby protecting hepatic cells from apoptosis and necrosis.
Safety & warnings
Contraindications
- Rabbits and other hindgut fermenters (converted to toxic lithocholic acid)
- Biliary obstruction
- Biliary fistulas
- Cholecystitis
- Pancreatitis
- Cholangitis (if complete obstruction is present)
Adverse effects
- Diarrhea
- Gastrointestinal upset (rare)
Precautions
Ursodiol is strictly contraindicated in rabbits and hindgut fermenters. Use with caution in patients with complications associated with gallstones (e.g., biliary obstruction, cholecystitis). While useful for chronic liver disease, some patients may experience further impairment of bile acid metabolism. It will not dissolve calcified radiopaque stones or radiolucent bile pigment stones.
Drug interactions
May bind to ursodiol, thereby reducing its efficacy
May bind to ursodiol, thereby reducing its efficacy
Theoretical concern that chronic administration in cats may lead to taurine deficiency
Monitoring
- Efficacy via ultrasonography for gallstones
- Improved liver function tests for chronic hepatic disease
- SGPT/SGOT (AST/ALT) on a routine basis
Pharmacokinetics
Absorption
Well absorbed from the small intestine after oral administration (up to 90% in humans).
Distribution
Enters the portal circulation. Ursodiol detected in the systemic circulation is highly bound to plasma proteins.
Metabolism
Extracted by the liver and conjugated with either taurine or glycine, then secreted into the bile. Undergoes entero-hepatic cycling and bacterial degradation.
Elimination
Mostly eliminated in the feces after being oxidized or reduced to less soluble compounds. Very little is detected in the urine.
Overdose
Overdosage of ursodiol would most likely cause diarrhea.
Treatment:
- Supportive therapy.
- Oral administration of an aluminum-containing antacid (e.g., aluminum hydroxide suspension) to bind the drug.
- Gastric emptying (if large overdose occurred recently) with concurrent administration of activated charcoal or cholestyramine suspension.
Available products
Formulations
- Oral Capsules
- Oral Tablets
Human-labeled
- Ursodiol Oral Capsules: 300 mg (Actigall & generic)
- Ursodiol Oral Tablets: 250 mg & 500 mg (URSO 250 & URSO Forte; generic)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store capsules at room temperature (15-30°C) in tight containers unless otherwise specified by the manufacturer.
Client information
- Give with food: Ursodiol dissolves more rapidly in the presence of bile or pancreatic juice, so it is best administered with a meal.
- Patience is key: Liver disease management is often a long-term process. Do not stop the medication without consulting your veterinarian.
- Monitor for side effects: While generally very safe, watch for signs of diarrhea or gastrointestinal upset and report them to your veterinarian.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.