How do the medications work?
Prolactin is normally inhibited (suppressed) by the hypothalamic (brain)hormone, dopamine. Drugs known as dopamine agonists act like dopamine to inhibit prolactin production. Dopamine agonists available in the U.S. include bromocriptine (Parlodel) and pergolide (Permax). A very effective drug, Norprolac, is only available in Europe and Canada. A newer dopamine agonist, cabergoline (Dostinex) is now FDA approved and available in the U.S. Bromocriptine and pergolide are usually given 1 to 3 times a day, cabergoline is given once or twice a week. All of these drugs act on the tumor in the same way – by inhibiting or reducing the amount of prolactin made by the tumor and thus causing the tumor to shrink. Over 90% of patients treated with these medications have a decrease in prolactin and in tumor size. Some patients are not able to take these medications because of side effects (nausea, vomiting, nasal stuffiness, and constipation). The newer medication, cabergoline is associated with fewe
