SpAMDA
SpAMDA, also known as spiro-AMDA or as spiro[9,10-dihydroanthracene]-9,3'-pyrrolidine, is a serotonin 5-HT2A receptor antagonist of the phenethylamine family. It is a tricyclic and spiro cyclized phenethylamine and is an analogue of AMDA. The drug shows high affinity for the serotonin 5-HT2A receptor (Ki = 4 nM) and has 5-fold higher affinity than AMDA. Its A2 value for serotonin 5-HT2A receptor antagonism is 79 nM. In addition to the serotonin 5-HT2A receptor, SpAMDA shows 6-fold lower affinity for the serotonin 5-HT2C receptor (Ki = 24 nM), but no affinity for several other targets, such as the dopamine D2 receptor among others.