There are a number of drugs that are currently used to manage hyperadrenocorticism. Trilostane has recently been licensed in the U.S. for this purpose and has proven to be a very effective drug with lower incidence of side effects than some of our other options, particularly, Lysodren.

Trilostane treats hyperadrenocorticism by interfering with the production of cortisol (as well as other adrenal steroid hormones). Since it does not kill any adrenal cells (as lysodren does), the effects of the drug are usually reversible with discontinuation or reduction in dosage.

What are the side effects of Trilostane?

Some of our patients from Alta Loma, Rancho Cucamonga, Upland, Ontario, Claremont, Fontana and the Inland Empire may exhibit reduced appetite and lethargy after treatment with this drug. If complete loss of appetite, vomiting, diarrhea and/or weakness occurs, it may be signs of over dosage and you should bring your pet in for evaluation.

In rare cases (1 in 50 patients), this drug can cause destruction of the adrenal gland and force the pet to develop Addison’s syndrome (hypoadrenocorticism). If this should occur, the patient will need supportive care and medications to re-supply the body with the hormones no longer being supplied by the adrenal glands. While most pets, will regain adrenal function in a few weeks, some may not and may require lifelong therapy.

How long will it take for Cushing’s symptoms to improve?

In most dogs, the heavy thirst and urination and panting aspect of Cushing’s will improve within 7 to 28 weeks. The heavy appetite will usually normalize within 3 months. Chronic skin changes may take up to a year to improve.

How do our veterinary team monitor the effectiveness of this drug?

10 days after starting the drug we will perform the following:

  • Physical Examination
  • Serum Biochemical Profile
  • ACTH stimulation test (4 hours after morning pill)

Our veterinary clinic’s goal for therapy is to obtain a cortisol level between 2 and 7 ug/dl from the ACTH stimulation test. If the results of the test are lower than this, we will most likely stop the drug for a week and restart it at a lower dose (25 –50% lower). This may require you obtaining an alternate strength of the drug as the capsules cannot be split.

Our veterinarians will need to repeat the ACTH Stimulation test at 6 weeks and at 12 weeks to ensure your pet’s safety and the effectiveness of the drug.

Once we have your pet regulated, we will have to repeat the ACTH Stimulation test every 6 months and a biochemical profile once yearly. Due to the potential danger of this drug if overdosed, refills will not be authorized without this regimen of testing.