Prolactin inhibitors are mainly used to treat hyperprolactinemia (high prolactin levels).[1]Agonists of the dopamineD2 receptor such as bromocriptine and cabergoline are able to strongly suppress pituitary prolactin secretion and thereby decrease circulating prolactin levels, and so are most commonly used as prolactin inhibitors.[1] D2 receptor agonists that are described as prolactin inhibitors include the approved medications bromocriptine, cabergoline, lisuride, metergoline, pergolide, quinagolide, and terguride and the never-marketed agent lergotrile.[3] Other dopamine agonists and dopaminergic agents, for instance levodopa (L-DOPA), can also inhibit prolactin secretion.[4]Antiestrogens such as aromatase inhibitors and GnRH analogues are also able to inhibit the secretion of prolactin, though not nearly as robustly as D2 receptor agonists, and as such, they are not usually used as prolactin inhibitors.