Tiospirone

Tiospirone (BMY-13,859), also sometimes called tiaspirone or tiosperone, is an atypical antipsychotic drug of the azapirone class. It acts as a 5-HT1A receptor partial agonist, 5-HT2A, 5-HT2C, and 5-HT7 receptor inverse agonist, and D2, D4, and α1-adrenergic receptor antagonist.

Tiospirone was tested in clinical trials for the treatment of schizophrenia in the late 1980s, and was found to have efficacy equivalent to that of typical antipsychotics without causing extrapyramidal side effects. However, development was not continued and it was never marketed.

Perospirone, another azapirone derivative with antipsychotic properties, was synthesized and assayed several years after tiospirone. It was found to be both more potent and more selective in comparison and was commercialized instead.