Metrenperone
Metrenperone is a serotonin 5-HT2 receptor antagonist which was never marketed. The drug also shows lower affinity for the α1-adrenergic and histamine H1 receptor and much lower affinity for the dopamine D2 receptor, but no affinity for the serotonin 5-HT1 and muscarinic acetylcholine receptors. It is a weak antagonist of the α1-adrenergic receptor in addition to its potent serotonin 5-HT2A receptor antagonism. Metrenperone has been investigated for use in veterinary medicine to treat acute respiratory distress in cattle and has also been studied for topical treatment of wounds as well as injuries. It was first described in the scientific literature by 1982.