Metergoline

Metergoline (INN, BAN), also known as methergoline and sold under the brand names Contralac (veterinary) and Liserdol (clinical), is a monoaminergic medication of the ergoline group which is used as a prolactin inhibitor in the treatment of hyperprolactinemia (high prolactin levels) and to suppress lactation.

Pharmacodynamics
Metergoline is a ligand of various serotonin and dopamine receptors.