Join Date: Aug 2009
Location: secret mountain valley
Trilostane is FDA approved for dogs which makes it's use in horses extralabel. This is not a problem because Pergolide is also extra label. The real issue is that Trilostane can have affects on mineralocorticoids too (aldosterone which regulates sodium and potassium) and can also necrose the adrenal gland sending the animal into addisonian crisis (eg HYPOadrenocorticism vs HYPER which = cushings).
Cushings in dogs and horses is not the same thing and is starting to be recognised as part of a complex rather than a simple disease. It more appropriately is referred to as Pars Pituitary Intermedia Dysfunction. In dogs it is the pars distalis which is affected. This is why pergolide which is a dopamine agaonist, can be used. It simply decreases the levels of ACTH and therefore the glucocorticoid levels without the severe side effects trilostane can have.
In a nutshell, trilostane is used in dogs because it is our best option. It has side effects but they are easily monitored and more cost effective in dogs. In horses Pergolide is a safer alternative with much fewer side effects.
As far as chasteberry is concerned, my main issue with that is that as a neutriceutical there is zero regulation on it, so even if it DOES work you have no way of controlling how much of the effective agent your animal gets from bottle to bottle (as there are always natural variations in plants, etc.) For me, I would rather treat with something that is delivering a controlled amount with known side effects, especially for something as serious as an endocrine disorder.