Cushing’s disease in dogs: treatment options compared
Checked against the Vetoryl FDA label and veterinary references: October 2026
Short answer
Cushing’s disease in dogs is too much cortisol, usually from a small pituitary tumor and less often from an adrenal tumor. Trilostane (Vetoryl), the FDA-approved treatment for both forms, controls it with daily capsules given with food and regular blood tests. Mitotane and selegiline are alternatives, and surgery can cure some adrenal tumors. Treatment controls the disease rather than curing it in most dogs.
Cushing’s disease treatments for dogs at a glance
- Trilostane (Vetoryl)FDA-approved for both formsUsed for: Pituitary and adrenal Cushing’sHow it is given: Capsules with food, once or twice a dayWhat to watch for: Lethargy, vomiting, diarrhea or weakness can mean cortisol is too lowWhere to get it: Vet or veterinary pharmacy
- Mitotane (Lysodren)Human medicine used off-labelUsed for: Mainly pituitary Cushing’sHow it is given: Loading phase, then weekly dosesWhat to watch for: Needs very close monitoring; can destroy too much adrenal tissueWhere to get it: Pharmacy, with your vet’s prescription
- Selegiline (Anipryl)FDA-approved for mild pituitary Cushing’sUsed for: Uncomplicated pituitary Cushing’sHow it is given: Once a dayWhat to watch for: Fewer side effects, but helps fewer dogsWhere to get it: Vet or veterinary pharmacy
- SurgeryAdrenalectomyUsed for: Adrenal tumorsHow it is given: Removal of the affected glandWhat to watch for: Major surgery; can cure when the tumor has not spreadWhere to get it: Surgical specialist
- Radiation therapyFor pituitary tumorsUsed for: Large pituitary tumorsHow it is given: A course of treatmentsWhat to watch for: Specialist centers onlyWhere to get it: Referral
| Treatment | Used for | How it is given | What to watch for | Where to get it |
|---|---|---|---|---|
| Trilostane (Vetoryl)FDA-approved for both forms | Pituitary and adrenal Cushing’s | Capsules with food, once or twice a day | Lethargy, vomiting, diarrhea or weakness can mean cortisol is too low | Vet or veterinary pharmacy |
| Mitotane (Lysodren)Human medicine used off-label | Mainly pituitary Cushing’s | Loading phase, then weekly doses | Needs very close monitoring; can destroy too much adrenal tissue | Pharmacy, with your vet’s prescription |
| Selegiline (Anipryl)FDA-approved for mild pituitary Cushing’s | Uncomplicated pituitary Cushing’s | Once a day | Fewer side effects, but helps fewer dogs | Vet or veterinary pharmacy |
| SurgeryAdrenalectomy | Adrenal tumors | Removal of the affected gland | Major surgery; can cure when the tumor has not spread | Surgical specialist |
| Radiation therapyFor pituitary tumors | Large pituitary tumors | A course of treatments | Specialist centers only | Referral |
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Signs and diagnosis
Typical signs are drinking and urinating more, a big appetite, panting, a pot-bellied look, thin skin, hair loss and muscle weakness, usually in middle-aged to older dogs. Diagnosis uses blood tests such as the ACTH stimulation or low-dose dexamethasone suppression test, and an abdominal ultrasound helps tell the pituitary form from an adrenal tumor.
Several signs overlap with an underactive thyroid; see hypothyroidism in dogs for how the two compare.
Monitoring on trilostane
The dose is individual and adjusted with testing. Under the Vetoryl label, your vet rechecks your dog about 10 to 14 days after starting and after every dose change, with an ACTH stimulation test done 4 to 6 hours after a dose and blood tests including electrolytes, then at 30 days, 90 days and every 3 months once the dose is stable. Give the capsules with food, which improves absorption, and at the same time each day.
As treatment works, thirst, urination and appetite usually fall toward normal within weeks; skin and coat take longer.
Signs that cortisol is too low
- Lethargy, weakness or collapse.
- Vomiting, diarrhea or not eating.
- If these appear, stop the medicine and call your vet straight away, because too little cortisol can be dangerous.
- A sudden large drop in drinking or appetite is also worth a call.
Handling the capsules
Do not open or divide the capsules, and wash your hands after giving them. People who are pregnant or trying to conceive should avoid handling them.
Conditions that come with it
Cushing’s raises the risk of urinary infections, high blood pressure, blood clots and diabetes, so your vet may check for these over time. See diabetes in dogs and cats.
Cost
Vetoryl is the FDA-approved trilostane product. Compounded trilostane is sometimes used, but its strength can vary, so discuss it with your vet before switching. The blood tests are a major part of the cost, so ask your vet about the monitoring plan when comparing options.
Frequently asked questions
Can Cushing’s disease in dogs be cured?
Most cases are controlled rather than cured, with lifelong medicine. Surgery to remove an adrenal tumor that has not spread can cure that form.
What are the side effects of trilostane?
Most dogs do well. Signs that cortisol has fallen too low, such as lethargy, vomiting, diarrhea, weakness or not eating, mean you should stop the medicine and call your vet straight away.
How often does a dog on Vetoryl need blood tests?
About 10 to 14 days after starting and after every dose change, then at 30 days, 90 days and every 3 months once stable, using an ACTH stimulation test 4 to 6 hours after a dose.
Does every dog with Cushing’s need treatment?
Vets usually treat when signs affect quality of life or health. Your vet will weigh the signs, test results and other conditions with you.