Terguride (INN) is a serotonin antagonist. It is used for the treatment of hyperprolactinemia. Terguride is an oral, potent antagonist of 5-HT2B and 5-HT2A (serotonin) receptors. Serotonin stimulates the proliferation of pulmonary artery smooth muscle cells, and induces fibrosis in the wall of pulmonary arteries. Together, this causes vascular rem...