As far as I know there are several options of treatments, and depending on the kind of cushings she has, there is even surgery.
The treatment with trilostane is
the latest, and with
the least amount
of side effects, once you get the dose right (what sometimes take a few tries), the dog can live a "normal" life, at least mine does, however it can get a little pricey, as you not only have to pay for the medicine but for several blood tests a year to make sure the dose is still correct.