I changed from Prascend to compounded pergolide in oil several years ago, when my two PPID thoroughbreds hit doses required in the teens.
This formulation kept them in the reference range for years, with appropriate testing and dose adjustment. As a vet I am fortunate to be able to manage all of this myself.
My current crop of 3 PPID horses have also been on the oil preparation for years, keeping their ACTH in the mid- high-teens. They are routinely tested twice a year and the dose adjusted. Currently they are on between 4 and 8 mg of pergolide mesylate.
It’s easy to adjust and simple to administer, and at least in my case, appears to have very good stability.