Trilostane is an inhibitor of 3 β-hydroxysteroid dehydrogenase used in the treatment of Cushing’s syndrome.

It was withdrawn from the United States market in April 1994. However was recently approved in 2008 for the treatment of Cushing’s disease (hyperandrenocorticism) in dogs.

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. Vetoryl should not be given to a dog that

has kidney or liver disease takes certain medications used to treat heart disease is pregnant The safety and effectiveness of Vetoryl 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 (selegiline), is FDA-approved to treat Cushing’s disease in dogs, but only to treat uncomplicated, pituitary-dependent Cushing’s.

It has been used as a progesterone inhibitor.

A number of compounding pharmacies in the US sell the product, although it is not approved for use. FDA’s enforcement discretion makes action unlikely.

Chemistry

The compound is prepared from testosterone in a four step synthesis.