Cinanserin
Cinanserin is a serotonin 5-HT2A and 5-HT2C receptor antagonist which was discovered in the 1960s and was never marketed. It has about 50-fold higher affinity for the 5-HT2A receptor than for 5-HT2C, and very low affinity for 5-HT1 receptors. The drug also inhibits the 3C-like protease of SARS-CoV-1 and SARS-CoV-2, but with much lower affinity.