Pergolide Mesylate is a dopamine agonist used to treat pituitary pars intermedia dysfunction (PPID), commonly know as equine Cushings disease. Pergolide compound powder is a loose powder in a bulk, 30-dose container. The powder is apple-flavored and has an expiration of 30 days. You may also want to consider Pergolide capsules- a more cost-effective and stable alternative to Pergolide powder.