Metrenperone (, , ; developmental code name R-50970) is a serotonin 5-HT<sub>2</sub> receptor antagonist which was never marketed. The drug also shows lower affinity for the ñ<sub>1</sub>-adrenergic and histamine H<sub>1</sub> receptor and much lower affinity for the dopamine D<sub>2</sub> receptor, but no affinity for the serotonin 5-HT<sub>1</sub> and muscarinic acetylcholine receptors. It is a weak antagonist of the ñ<sub>1</sub>-adrenergic receptor in addition to its potent serotonin 5-HT<sub>2A</sub> 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.