It was withdrawn from human use in the United States market in April 1994. The drug is available in the United Kingdom for use in humans under the brand name Modrenal and is used for treatment of Cushing's disease and for breast cancer treatment. It was approved in the United States in 2008 for the treatment of Cushing's disease (hyperadrenocorticism) in dogs under the brand name Vetoryl. It was available by prescription in the UK under the Vetoryl brand name for some time before it was approved in the US. The drug is also used to treat the skin disorder Alopecia X in dogs. It is also the first drug approved to treat both pituitary- and adrenal-dependent Cushing's in dogs. This prescription drug works by stopping the production of cortisol in the adrenal glands. In studies of the drug, the most common side effects were vomiting, lack of energy, diarrhea, and weight loss. Trilostane should not be given to a dog that:
is pregnant, nursing or intended for breeding 
The safety and effectiveness of trilostane were shown in several studies. Success was measured by improvements in both blood test results and physical symptoms (increased appetite and activity level, and decreased panting, thirst and urination).
Only one other drug, Anipryl (veterinary brand name) selegiline, is FDA-approved to treat Cushing's disease in dogs, but only to treat uncomplicated, pituitary-dependent Cushing's. The only previous treatment for the disease was the use of Mitotane (brand name Lysodren) off-label.
A number of compounding pharmacies in the US sell the product. Since the US approval of Vetoryl in December 2008, compounding pharmacies are no longer able to use a bulk drug product for compounding purposes, but must prepare the compounded drug from Vetoryl.