Updated September 25, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: Vetoryl (trilostane) is an FDA-approved medication for treating Cushing’s disease (hyperadrenocorticism) in dogs. It reduces the adrenal glands’ production of cortisol. It’s given with food, usually once or twice daily, and requires regular blood tests to adjust the dose, because too much can cause dangerously low cortisol. Alternatives include mitotane and, for adrenal tumors, surgery.
Signs of Cushing’s disease
- Increased thirst, urination, and appetite
- Pot-bellied appearance
- Panting
- Thin skin and hair loss
- Recurring skin or urinary infections
How Vetoryl is used
- Given with food
- Recheck exams and blood tests (such as ACTH stimulation or cortisol tests) after starting, after dose changes, and periodically
- Doses are adjusted based on signs and test results
Side effects to watch for
- Reduced appetite, vomiting, diarrhea, lethargy, or weakness can signal cortisol that’s too low. Stop the medication and call your vet
- Rarely, a serious adrenal crisis
Alternatives
- Mitotane: an older medication that destroys adrenal tissue, needing careful monitoring
- Surgery: removal of an adrenal tumor in suitable cases
- Radiation for some pituitary tumors
- Monitoring only for dogs with mild signs, in discussion with your vet
What to avoid
- Giving it on an empty stomach
- Skipping monitoring tests
- Supplements marketed as “natural Cushing’s treatments,” which lack good evidence
Sources
- Dechra: Vetoryl (trilostane) capsules product label
- Behrend EN, et al. Diagnosis of spontaneous canine hyperadrenocorticism: 2012 ACVIM consensus statement (small animal). J Vet Intern Med. 2013
- Merck Veterinary Manual: Cushing’s disease in dogs
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.