if it causes weight gain why would it be used for cushings, is the D2 agonist then responsible for causing the weight loss and negating any weight gain from the cyproheptadineWorth mentioning that I read a couple of times about Cushing syndrome (too much ACTH from the pituitary causes too much Cortisol) in horses being treated with a a so called a so D2 agonist (Pergolide) and Cyproheptadine.
I find that combination quite interesting.
It is quite interesting how they refer to it in veterinary use as anti serotonin syndrome rather the preferred term of some, an anti-histamine, which I think it is a underwhelming term for Cyproheptadine.