Last Updated: 07/05/2025
Trilostane (Vetoryl) Medication Guide
Learn all about the use of Vetoryl in pets: how it works it's uses side effects and more.
Author: Dr Jenny Eales BVSc (Hons)
Reading Time: 19 minutes - medium read
Last Updated: 07/05/2025
Learn all about the use of Vetoryl in pets: how it works it's uses side effects and more.
Author: Dr Jenny Eales BVSc (Hons)
Reading Time: 19 minutes - medium read
Trilostane is a short acting competitive inhibitor of the enzyme used for synthesis of cortisol and all other steroids. It inhibits the production of glucocorticoids, and to a lesser extent mineralocorticoids and sex hormones. It acts on the adrenal gland to stop it making excessive amounts of steroids.
Trilostane is used for the treatment of pituitary-dependent and adrenal-dependent hyperadrenocorticism (Cushing's syndrome) in dogs.
It may also be used off label in cats and horses to treat hyperadrenocorticism and in dogs for treatment of alopecia X. Off-label use means that it has not been registered for use in these cases so please follow the directions of your treating Veterinarian closely.
Trilostane comes in capsule form (Vetoryl) and is taken orally once or twice a day with food.
Vetoryl is available in 5mg, 10mg, 30mg, 60mg and 120mg capsules. A combination of different sized capsules may be needed to make the correct dose. Vetoryl capsules should never be opened or divided.
Trilostane starts to work approximately 1-2 hours after ingestion, but you may not notice a change in your pets symptoms until 9-12 days after starting the medication.
If you are concerned that there are no noticeable changes please contact your veterinarian.
While trilostane is usually well tolerated by dogs, side effects can occur. These are usually mild and self limiting. The most common are:
Other more serious potential side effects include:
It is extremely important to follow your veterinarians advise regarding monitoring and dose changes while your pet is taking Trilostane. If you notice anything unusual, contact your veterinarian immediately.
Drugs that can interact with trilostane include:
Trilostane may interact with other medications and food, so it is extremely important to let you veterinarian know of any medication (including supplements, vitamins and herbal therapies). Do not give any new food or medications without first talking to your veterinarian.
If your pet experiences any unusual reactions when taking multiple medications, contact your veterinarian.
Store in a childproof container below 25°C and away from heat and direct sunlight. Keep the blister strips in the carton.
To avoid accidental ingestion, administer the medication to your pet immediately after removal from the package, and observe your pet closely to ensure that the entire dose has been consumed. Keep out of reach and sight of children.
Vetoryl capsules are usually administered once daily with food, but in some cases your veterinarian may advise twice daily administration.
The starting dose is approximately 2 - 6 mg/kg, based on available combinations of capsule sizes. This dose may need to be changed depending on your pet's response to the medication.
It is crucial that you follow your Veterinarian's specific instructions regarding dosage for your individual pet.
If you miss giving your pet a dose of Vetoryl give it as soon as you remember. However, if it is close to the time for the next dose, skip the missed dose and resume the dosing schedule as normal - do not give two doses at once.
Do not stop giving your pet Trilostane without first discussing it with your veterinarian. Any cessation or change to your pet's medication should only be done under the close supervision and recommendation of your treating Veterinarian.
Missed doses reduce the effectiveness of therapy. This drug will likely need to be taken for the rest of your pet's life.
If you suspect or know that your pet has taken too much Trilostane contact your veterinarian or an emergency veterinarian immediately.
It is very important that you follow your veterinarian's advice regarding when to take your pet back for monitoring or blood tests while your pet is taking trilostane.
Periodic blood work to monitor your petâs health and the effects that taking this medication is having on your pet's body is recommended as long-term therapy is often necessary. Dose adjustments may be made based upon these results and an assessment of how your pet is responding clinically.
