Ursodiol (Ursodeoxycholic Acid): veterinary dose and monograph

At a glance

Drug class

Gastrointestinal

Also known as

UDCA, Actigall, Udiliv, Ursocol

Species with doses

Dogs, Cats and Birds

General dose range

10–15 mg/kg PO q24h (or divided q12h) with food — check the species tables for the indication

Routes

PO

Last reviewed

1 October 2026

Indications

• Chronic hepatitis / cholangiohepatitis (cats) — hepatoprotection
• Cholestatic liver disease (improves bile flow)
• Biliary sludge and gallbladder mucocele (medical management of non-obstructive cases)
• Adjunct in many chronic hepatobiliary disorders

Ursodiol (Ursodeoxycholic Acid) dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Chronic/cholestatic liver disease: Papich 5e: 10–15 mg/kg q24h PO (15 mg/kg most often). Plumb’s p.1156: 10–15 mg/kg PO once daily (Webb & Twedt); 11–15.4 mg/kg once daily or divided twice daily (Tams). Give with food; confirm the bile duct is not obstructed.

Cats

• Cholangitis / cholangiohepatitis: Papich 5e: 10–15 mg/kg q24h PO. Plumb’s p.1156: 10–15 mg/kg once daily (Webb & Twedt); 10 mg/kg/day (Zoran); about ⅙ of a capsule mixed with food (Tams). Rule out extrahepatic bile duct obstruction first.

Birds

• Liver disease (adjunct): Plumb’s p.1156 (Oglesbee 2009): 10–15 mg/kg PO once daily.

Contraindications

Complete biliary obstruction (increasing bile flow against an obstruction is harmful — confirm patency first; a developing/ruptured mucocele needs surgery). CONTRAINDICATED in rabbits and other hindgut fermenters — ursodiol is converted to toxic lithocholic acid (Plumb's). Known hypersensitivity. Use with caution where surgical biliary disease is the real problem.

Species-specific warnings

Cats: A mainstay for the feline cholangitis/cholangiohepatitis complex — pair with appropriate antibiotic and/or immunosuppressive therapy based on the cholangitis type and biopsy.

Adverse effects

• Generally very well tolerated
• Occasional diarrhoea / GI upset
• Rare vomiting

Drug interactions

• Bile-acid sequestrants (cholestyramine), aluminium antacids: bind ursodiol and reduce its absorption — separate dosing
• No major systemic CYP interactions

Pregnancy and lactation

Limited veterinary data; generally regarded as low-risk (it is a physiological bile acid). Use if clearly indicated.

Monitoring

• Liver enzymes / bilirubin and bile acids over time (response)
• Imaging of the biliary tree (confirm patency; monitor mucocele/sludge)
• GI tolerance
• Overall hepatobiliary disease response (often part of a multidrug plan)

Toxicity and overdose

Very wide safety margin — overdose typically causes only diarrhoea/GI upset. The important caution is mechanistic, not toxic: do not push bile flow in a completely obstructed biliary tree.

Management: Supportive; no specific antidote needed. Manage diarrhoea symptomatically. Reduce dose if GI upset.

Clinical pearls

• A cornerstone hepatoprotectant for chronic/cholestatic liver disease and feline cholangitis — improves bile flow and swaps toxic bile acids for benign ones
• CONFIRM the bile duct is patent first — don't drive bile flow against a complete obstruction (that's a surgical problem)
• Give with food; commonly combined with SAMe/silybin (and antibiotics/immunosuppressants for the underlying disease)
• Very safe and well tolerated — diarrhoea is the only common nuisance

Mechanism of action

Ursodeoxycholic acid is a non-toxic, hydrophilic bile acid. It (1) promotes bile flow (choleresis), (2) competitively reduces the proportion of toxic, hydrophobic bile acids in the bile-acid pool (cytoprotective to hepatocyte and cholangiocyte membranes), and (3) exerts anti-inflammatory, immunomodulatory and anti-apoptotic effects on liver cells. The net effect is reduced cholestatic hepatocellular injury.

Formulations and products

• 150 mg tablet
• 300 mg tablet/capsule
• Suspension (compounded) 25–50 mg/mL
• Udiliv — 150 / 300 mg tablet, Tablet (human-label)
• Ursocol — 150 / 300 mg tablet, Tablet (human-label)

Storage

Tablets/capsules: 15–30 °C, dry. Compounded suspension per pharmacy beyond-use date.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other gastrointestinal drugs

• Silymarin (Milk Thistle / Silybin)
• Sucralfate
• Sulfasalazine
• Tylosin

Frequently asked questions