Trilostane is a drug able to block the synthesis of progesterone from pregnenolone, dependent on the enzyme 3β-hydroxysteroid dehydrogenase/Δ⁵⁻⁴ isomerase. As a consequence of this effect, it is used to treat endocrinological diseases such as Cushing’s syndrome, especially in dogs. Because of the modulatory effects of trilostane on the hypothalamic–pituitary–adrenal axis, trilostane administration causes an increase in brain levels of neurosteroids with anticonvulsant properties, as in the case of allopregnanolone. Allopregnanolone is also of interest in curing depression, suggesting that trilostane might represent a tool to address neurological and psychiatric disorders. In this review, we investigated the historical development of this drug and its current use, mechanisms, and possible developments. By searching the literature from 1978 to 2025, we identified 101 papers describing studies with trilostane. Precisely, 55 were about dogs and trilostane, 3 were on cats, and 23 were with other animals. Some studies (15) were also designed with human patients. The main disease treatment with trilostane was hyperadrenocorticism. However, we also found two preclinical papers on trilostane’s potential use in psychiatric diseases and three on trilostane’s potential use in neurological disorders. Moreover, few clinical and preclinical studies suggested the involvement of neurosteroids modulated by trilostane in different neurological disorders, thus opening a possible new perspective for the use of this drug.

Trilostane is a drug able to block the synthesis of progesterone from pregnenolone, dependent on the enzyme 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase. As a consequence of this effect, it is used to treat endocrinological diseases such as Cushing’s syndrome, especially in dogs. Because of the modulatory effects of trilostane on the hypothalamic-pituitary-adrenal axis, trilostane administration causes an increase in brain levels of neurosteroids with anticonvulsant properties, as in the case of allopregnanolone. Allopregnanolone is of interest also in curing depression, suggesting that trilostane might represent a tool to address neurological and psychiatric disorders. In this review, we investigated the historical development of this drug, its current use, mechanisms, and possible developments. By searching the literature from 1978 to 2025, we identified 101 papers describing studies with trilostane. Precisely, 55 were about dogs and trilostane, 3 on cats, and 23 with other animals. Some studies (15) were also designed with human patients. The main disease treatment with trilostane was hyperadrenocorticism. However, we also found two preclinical papers on trilostane's potential use in psychiatric diseases and three on trilostane in neurological disorders. Moreover, few clinical and preclinical studies suggested the involvement of neurosteroids modulated by trilostane in different neurological disorders, thus opening a possible new perspective for the use of this drug.