Trilostane for Dogs - Uses, Dosage and Side Effects

Josie F. Turner
By Josie F. Turner, Journalist specialized in Animal Welfare. June 28, 2022
Trilostane for Dogs - Uses, Dosage and Side Effects

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There are many drugs which are used in both veterinary in human medicine, but trilostane has a rare distinction. While it was previously used in human medicine in the USA, it has been withdrawn from such purposes. Since this withdrawal, it has been approved for use in veterinary medicine. Used mainly to treat Cushing's syndrome in dogs, trilostane is seen as being more appropriate than previous drugs used to treat this condition. These latter drugs include mitotane, a product which had the serious adverse effect of damaging adrenal glands.

At AnimalWised, we examine trilostane for dogs. We look into more detail at its uses, dosage and side effects when used to treat canines.

  1. What is trilostane for dogs?
  2. Trilostane for dogs uses
  3. Dosage of trilostane for dogs
  4. Side effects of trilostane for dogs
  5. Contraindications of trilostane for dogs

What is trilostane for dogs?

Trilostane is a steroid hormone analogue drug that inhibits the enzyme responsible for synthesizing adrenal hormones. Specifically, these hormones are cortisol and aldosterone. This action makes it an effective medication for the treatment of hyperadrenocorticism, also known as Cushing's syndrome in dogs. This is an endocrine disease characterized by the presence of chronic and excessive levels of cortisol and aldosterone.

Currently, trilostane for dogs is available in capsules of 5, 10, 30, 60 and 120 mg. The price will depend on various factors, including whether or not it can be purchased on insurance. Generally speaking in the USA, the trilostone for dogs price is about $50 for 30 pills.

Trilostane for dogs uses

When administering trilostane to your dog, it is important to know it is not a curative medication. It is a drug which is used exclusively to treat adrenal hormone imbalance in dogs. Specifically, this means it is used to manage the group of symptoms which is known as Cushing's syndrome in dogs.

Trilostane works by inhibiting the cortisol productions in the adrenal and pituitary glands. In some cases, Cushing's disease in dogs may be due to a tumor on the glands. In these cases, initial surgery to remove any masses may be required, with trilostane being used to manage the symptoms afterwards.

Dosage of trilostane for dogs

The initial dose of trilostane for dogs for the treatment of Cushing's disease is 2 mg/kg of body weight. The dose can be administered every 24 hours. For the best response, it is recommended to divide the dose into two doses per day. From this initial dose, the animal's response should be monitored and the dose adjusted accordingly:

  • The persistence of the typical symptoms of Cushing's disease (increased water consumption, increased urine production, increased appetite and panting) means the dose of trilostane is insufficient. In these cases, the veterinarian will increase the dose.
  • Addison's disease in dogs is the opposite of Cushing's disease, i.e. the dog's cortisol levels are too low. When symptoms typical of Addison's disease in dogs such as vomiting, diarrhea, weakness and depression appear, the dose will need to be reduced.
  • If there are no clinical signs, it means the effective dose has been reached and the symptoms are being managed correctly.

Dose adjustment reviews should initially be carried out every week, then every month, then every 3 months and, subsequently, every 3-6 months. It should be noted that dose adjustments should always be prescribed by a veterinary professional.

How to administer trilostane for dogs

Once the dose has been arranged by the veterinarian, it is important to point out how to administer trilostane for dogs:

  • The drug comes in the form of hard capsules, so it must be administered orally and with food.
  • The capsules should not be opened or divided as the content may cause skin and eye irritation.

Side effects of trilostane for dogs

Trilostane is a relatively safe drug. However, its technical data sheet lists some adverse reactions that should be known:

  • When the necessary dose is exceeded, signs associated with hypoadrenocorticism (Addison's syndrome) appear. These can include dizziness, lethargy, anorexia, vomiting and diarrhea. Normally, these signs are reversible after withdrawal of treatment.
  • In severe overdose, an acute case of Addison's syndrome may occur.
  • Infrequently, ataxia (incoordination), hypersalivation, swelling, muscle tremors and skin changes may appear.
  • A few isolated cases of necrosis of the adrenal glands have been reported.
  • A small number of cases of sudden death have been described.

In addition, it should be noted that treatment with trilostane can reveal the presence of kidney failure or arthritis. Learn more with our article on arthritis in dogs.

Contraindications of trilostane for dogs

Trilostane administration is contraindicated in the following situations:

  • Primary liver disease
  • Kidney failure
  • Dogs under 3 kg
  • Pregnant or lactating bitches
  • Allergy or hypersensitivity to trilostane (or any excipients)
  • Recent treatment with mitotane

If a dog has undergone a course of mitotane treatment, it is important to wait a period of one month between the cessation of mitotane administration and the beginning of trilostane treatment.

In addition, trilostane should be administered with special caution in the following cases:

  • Elderly dogs: liver and kidney markers (liver enzymes, electrolytes, urea, and creatinine) should be monitored to ensure the absence of liver or kidney failure, typical of older dogs. Learn more with our article on high creatinine levels in dogs.
  • Diabetes mellitus: the concomitant presence of Cushing's syndrome and diabetes requires specific monitoring
  • Anemia: blood cell volume and hemoglobin should be monitored in dogs with anemia since trilostane can produce significant decreases in these parameters.
  • Other drugs: simultaneous treatment with potassium-sparing diuretics or ACE inhibitors (angiotensin-converting enzyme inhibitors) can cause health issues, so they need to be monitored by the vet.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Trilostane for Dogs - Uses, Dosage and Side Effects, we recommend you visit our Medicine category.

  • Sands, C., Lopez, M., Melian, C., & Pérez-Alenza, Mª.D. (2005). Trilostane. A new option in the treatment of hyperadrenocorticism. Clin. Vet. Peq. Anim., 25(3), 189-192.
  • Spanish Agency for Medicines and Health Products. (AEMPS). Technical sheet or summary of product characteristics. Vetoryl 5 mg hard capsules for dogs. Retrieved from:
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Trilostane for Dogs - Uses, Dosage and Side Effects