Dostinex Active ingredient: cabergoline $3.27 for pill Dostinex is used to treat hormonal imbalance with much prolactin in the blood to reduce or prevent breast milk production. Cabgolin Active ingredient: cabergoline $3.99 for pill Cabgolin (Cabergoline) is used to treat a hormone imbalance in which there is too much prolactin in the blood (also called hyperprolactinemia).