List of products in the National Drug Code with proprietary name . This medication is used to treat high levels of prolactin hormone in your body. High levels of prolactin in women can cause symptoms such as unwanted breast milk and missed periods and can cause difficulty becoming pregnant. High levels of prolactin in men can cause symptoms such as enlarged breasts and decreased sexual ability/desire. Cabergoline is an ergot medication and works by blocking the release of prolactin from the pituitary gland.