Ursodiol (Ursodeoxycholic Acid)

Ursodiol, or ursodeoxycholic acid, is a hydrophilic bile acid used as an adjunct in selected hepatobiliary disorders. Its principal veterinary role is support of bile flow and reduction of potentially injurious bile-acid exposure in nonobstructive cholestatic disease. Clinical evidence for individual canine and feline disorders remains less extensive than the biochemical rationale.

Group

Hydrophilic bile acid and choleretic

Mechanism of Action

Ursodiol becomes part of the bile-acid pool and can shift its composition toward less hydrophobic, less cytotoxic bile acids. It promotes bile secretion and may support bicarbonate-rich flow, reducing exposure of hepatocytes and cholangiocytes to damaging bile constituents. Additional cytoprotective and immunomodulatory effects have been proposed. The clinical impact depends on the underlying hepatobiliary disorder.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Hepatobiliary disease	10–15 mg/kg	PO	Every 24 h	15 mg/kg once daily is the commonly used reported amount.
Hepatobiliary disease	11–15.4 mg/kg	PO	Every 24 h
Hepatobiliary disease divided daily amount	5.5–7.7 mg/kg	PO	Every 12 h	Half of explicitly stated total daily 11-15.4 mg/kg; not the full daily amount twice daily.

Cats

Use / stage	Dose	Route	Schedule	Instructions
Hepatobiliary disease	10–15 mg/kg	PO	Every 24 h	15 mg/kg once daily is the commonly used reported amount.
Hepatobiliary disease	11–15.4 mg/kg	PO	Every 24 h
Hepatobiliary disease divided daily amount	5.5–7.7 mg/kg	PO	Every 12 h	Half of explicitly stated total daily 11-15.4 mg/kg; not the full daily amount twice daily.
Hepatobiliary disease	10 mg/kg	PO	Every 24 h

Birds

Use / stage	Dose	Route	Schedule	Instructions
Liver disease adjunct	10–15 mg/kg	PO	Every 24 h

Indications

Adjunctive treatment of selected nonobstructive cholestatic liver disease in dogs and cats.
Adjunctive treatment of selected cholangitis or chronic inflammatory hepatobiliary disease, with limited disease-specific outcome evidence.
Specialist medical management of selected cholesterol-containing gallstones where a supported dissolution strategy is appropriate.

Interactions

No specific veterinary interaction is established in the clinical guidance.

Adverse effects

Diarrhea or loose stool.

Toxicity

Excess usually causes diarrhea; provide supportive treatment according to exposure and clinical signs.

Preparations

Preparation	Form	Strength	Route
Ursodiol (Ursodeoxycholic Acid) 250 mg	Tablet	250 mg / tablet	PO
Ursodiol (Ursodeoxycholic Acid) 500 mg	Tablet	500 mg / tablet	PO
Ursodiol capsule 300 mg	Capsule	300 mg / capsule	PO

Monitoring and Administration

Give with meals and follow liver enzymes and bile acids. Gradual titration over 1-2 weeks can reduce GI effects; investigate hepatobiliary disease before choleretic therapy.

Reported oral suspension stability varies by vehicle, 35-60 days.