I'll ask my friend as her old fell pony is on Pregolide for his cushings. He is on two tablets per day and she gets them from the chemist rather than the vet as its cheaper.
She did make me laugh when she thought she could get it from the chemist for the price of an NHS prescription. I had to remind her that Impey wasn't an NHS patient. PMSL.
its a prescription med, HOWEVEr there is apparently a movement to remove pergolide as a licensed human drug (which is what it is, it isnt licensed in horses!) which might make it more difficult to get it soon!
However, sure your vets will be able to get you them in if you end up not being able to get them from a human pharmacy!