Vetoryl vs Mitotane: what's the difference?
How Vetoryl and Mitotane compare: what each is for, how it works, side effects and cost, side by side.
Last updated: October 2026 · 2 sources · see sources
Side by side
| Vetoryl | Mitotane | |
|---|---|---|
| Generic name | Trilostane | Mitotane |
| Brand names | Vetoryl | Lysodren |
| For | Dogs | Dogs |
| Prescription | Prescription | Prescription |
| Used for | Treats Cushing's disease (hyperadrenocorticism) in dogs. [1] | An older treatment for Cushing's disease and adrenal tumors in dogs. [2] |
| How it works | It blocks an enzyme the adrenal glands need to make cortisol. [1] | It destroys part of the adrenal gland tissue that makes cortisol. [2] |
| Common side effects | Tiredness, vomiting, diarrhea and low appetite, mostly early on. [1] | Vomiting and diarrhea. Low appetite, weakness or wobbliness can mean cortisol has dropped too low. [2] |
| Use with care | Too much can cause an Addison's-like crisis: weakness, collapse, vomiting. Regular rechecks with bloodwork are part of treatment. Not for pregnant dogs. [1] | Needs close vet monitoring. Wear gloves when handling. [2] |
| Full guide | Vetoryl guide | Mitotane guide |
Key differences
On the basics they are alike: same kind of animal, same way to get them. The differences are in how they work and what else they cover, shown in the table above.
Which one is right for my pet?
That is a call for your vet. They weigh your pet's age, weight, other health problems, other medicines and what you can realistically give at home.
Switching from Vetoryl to Mitotane is common, but do it only with your vet's plan.
Common questions
What is the difference between Vetoryl and Mitotane?
Both treat Cushing's disease in dogs. Vetoryl blocks cortisol production; mitotane is the older drug that destroys part of the adrenal tissue.
Is Vetoryl better than Mitotane?
Neither is better for every pet. Your vet chooses based on your pet's species, age, health history, other medicines and what you can manage at home.
Can my pet take Vetoryl and Mitotane together?
Only if your vet says so. Some medicines in the same family should not be combined, and others are often used together. Always check before adding or switching.
Do Vetoryl and Mitotane need a prescription?
Vetoryl: Yes. It needs a prescription from a veterinarian. Mitotane: Yes. It needs a prescription from a veterinarian.
Related
This page is general information for planning, not veterinary advice. Talk to your vet about your own pet.