Dr. Mark is a veterinarian with over 40 years of experience in the field. He works with dogs, cats, exotics, and livestock.
What Is Ursodiol and How Does It Work?
Ursodiol is a medication made of ursodeoxycholic acid (UDCA) in a microcrystalline cellulose filler. It is a type of bile acid available in liquid, tablet, or capsule form as Actigall, Urso, or Ursofalk. It is also sold as a generic product.
This drug is a hydrophilic bile acid that was originally extracted from black bear livers. (It is now made in a laboratory.) When you give ursodiol to your pet, their bile flow is increased, they produce less cholesterol, and the cholesterol already in their bile is dissolved so that gallstones cannot form.
This medication is not FDA-approved for dogs and cats but is a common extra-label drug to treat liver disease. (An extra-label drug is a medication that has not been FDA approved but is used to treat pets.)
What Is Ursodiol Used for in Dogs and Cats?
Ursodiol is used to treat dogs with chronic hepatitis and cats with lymphocytic plasmacytic cholangitis. (1) It is used as an adjunctive therapy in any inflammatory hepatobiliary disease and any other disease where bile toxicity in part of the pathology.
Other Uses for Ursodiol in Veterinary Medicine
Ursodiol may be effective in decreasing biliary sludge before gallstones are formed. (2) Ursodiol reduces the production of cholesterol and is effective at dissolving gallstones, so it is also used as an alternative to surgery when gallstones have already formed. (3)
This medication is also being prescribed for congenital portosystemic shunts, fatty liver disease, and several other diseases of the liver.
Ursodiol Dosage and Administration
The normal dose for ursodiol is 2.5–7 mg per pound twice a day. Ursodiol is given orally and should always be given with food. (Food increases the absorption and makes the pet less likely to become nauseous.) There are several different strength capsules available and a liquid formula for very small pets and those that will not accept pills.
What to Do If Your Pet Misses a Dose
If you forget to give a dose of ursodiol, just give the next capsule at the regular time. Do not give two doses at once.
How Long Does It Take for Ursodiol to Work in Dogs
Although ursodiol is absorbed within a few hours of being given, you will not begin to see any improvements for a few days. If your dog is being treated for gallstones, studies in humans have shown that ursodiol will take 3–6 weeks to dissolve them. (4) If your dog is being treated for hepatitis, liver enzymes may not show any changes for at least 4 weeks.
How Long Should My Dog Be on Ursodiol?
Dogs need to continue ursodiol treatment until liver enzymes are normal and all signs of liver disease have been resolved. Even if the bladder stones are resolved in 3–6 weeks, the veterinarian may decide to continue treating the dog for more than a year to clear up the biliary sludge.
Side Effects of Ursodiol
Ursodeoxycholic acid is a natural part of the body, and ursodiol is well tolerated. Some pets will have an upset stomach and diarrhea from this medication. Vomiting is rare but has been mentioned.
Allergic reactions are rare. If your pet starts to exhibit signs of an allergic reaction after taking ursodiol (such as hives, swelling, difficulty breathing, and sneezing), then be sure to contact your veterinarian immediately.
Can Ursodiol Cause Liver Problems in Dogs?
There have been some reports of dogs developing mild elevated liver enzymes, jaundice, and the liver becoming worse when on ursodiol. (5) However, since the dogs already have liver disease, there is no way to tell for sure if this problem is primary or secondary to the medication. When healthy dogs were treated with ursodiol, no liver pathology developed and liver enzyme values remained normal. (6)
Will Ursodiol Hurt My Dog?
Most dogs with liver disease benefit from ursodiol, but no medication is 100% safe. Some other problems have been reported in humans but not in dogs (e.g., immune suppression and pneumonia). (7)
Dogs with an obstructed biliary tract should not be taking this medication.
Risk Factors and Special Precautions
There is very little risk when giving this medication. It can cause some side effects but is eliminated from the pet’s body in 3–6 days after treatment has concluded. (7)
Known Drug Interactions
Any medications that your pet is taking should be discussed with your veterinarian when ursodiol is prescribed. This includes traditional Chinese medicines, herbal supplements, medicated foods, and vitamins.
There are some reported drug interactions. (8) Medications that interfere with ursodiol include:
- Cyclosporine (Atopica and other brands)
- Acetominophen (Tylenol)
- Antacids (magaldrate and others)
- Cholestyramine resin
Can My Pet Overdose on Ursodiol?
No overdoses have been reported in humans or dogs. Mice, rats, and dogs have been given large doses (10 grams/kg) and no symptoms of overdose were seen. An overdose was seen in a hamster, and the symptoms were excessive salivation, ataxia (disoriented with a wobbly gait), droopy eyelids, difficulty breathing, seizures, and coma. (9)
If you see any of those symptoms after giving a dose of ursodiol, take your dog to an emergency veterinarian immediately.
How Much Does Ursodiol Cost?
Dogs are usually dosed at less than 7 mg/pound daily, so it will generally cost about $1–$2 a day to treat a small dog with ursodiol. Liver enzymes need to be monitored before the dog is prescribed this medication and then checked periodically, so the major expense in ongoing care will be examination and laboratory costs.
If you don't feel like making a trip to the pharmacy, you can order this medication online.
How to Store Ursodiol
Ursodiol should be stored in the original labeled container that you purchased it in. It can be kept at room temperature. Keep out of direct sun, away from heat sources, and out of reach of children.
Can Ursodiol Capsules Be Opened?
Although there is no problem with opening the capsules, they should be given whole. Ursodiol is a bitter medication, and if you open the capsule and the dog tastes it, they may become difficult to treat.
If the capsule is too large or your pet is difficult to treat, use the liquid formula that is compounded with flavors (beef, chicken, bacon, and peanut butter).
(1) Meyer DJ, Thompson MB, Senior DF. Use of ursodeoxycholic acids in a dog with chronic hepatitis: effects on serum hepatic tests and endogenous bile acid composition. J Vet Intern Med. 1997 May-Jun;11(3):195-7. https://pubmed.ncbi.nlm.nih.gov/9183773/
(2) DeMonaco SM, Grant DC, Larson MM, Panciera DL, Leib MS. Spontaneous Course of Biliary Sludge Over 12 Months in Dogs with Ultrasonographically Identified Biliary Sludge. J Vet Intern Med. 2016 May;30(3):771-8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4913576/
(3) Allan F, Watson PJ, McCallum KE. Clinical features and outcomes in 38 dogs with cholelithiasis receiving conservative or surgical management. J Vet Intern Med. 2021 Nov;35(6):2730-2742. https://pubmed.ncbi.nlm.nih.gov/34714561/
(4) Salen G. Gallstone dissolution therapy with ursodiol. Efficacy and safety. Dig Dis Sci. 1989 Dec;34(12 Suppl):39S-43S. https://pubmed.ncbi.nlm.nih.gov/2689115/
(5) LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet]. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-. Ursodiol (Ursodeoxycholic Acid) [Updated 2017 Sep 25]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK548309/
(6) Deitz KL, Makielski KM, Williams JM, Lin H, Morrison JA. Effect of 6-8 weeks of oral ursodeoxycholic acid administration on serum concentrations of fasting and postprandial bile acids and biochemical analytes in healthy dogs. Vet Clin Pathol. 2015 Sep;44(3):431-6. https://pubmed.ncbi.nlm.nih.gov/26274488/
(7) Kotb MA. Molecular mechanisms of ursodeoxycholic acid toxicity & side effects: ursodeoxycholic acid freezes regeneration & induces hibernation mode. Int J Mol Sci. 2012;13(7):8882-8914. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3430272/
(8) Hempfling W, Dilger K, Beuers U. Systematic review: ursodeoxycholic acid--adverse effects and drug interactions. Aliment Pharmacol Ther. 2003 Nov 15;18(10):963-72. https://pubmed.ncbi.nlm.nih.gov/14616161/
(9) Axcan Scandipharm Inc. Drug Insert, Ursodiol https://www.accessdata.fda.gov/drugsatfda_docs/label/2008/020675s013lbl.pdf
This article is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from your veterinarian. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
© 2022 Mark dos Anjos DVM