Mesoridazine (brand name Serentil) is a phenothiazine antipsychotic. It was marketed in the U.S. for the treatment of schizophrenia, behavioral problems in mental deficiency and chronic brain syndrome, alcoholism and psychoneurotic symptoms, such as anxiety and tension. Due to the risk of serious cardiac events the indicated use of Serentil was limited to severely ill schizophrenic patients who fail other therapies. Based upon animal studies, mesoridazine acts indirectly on reticular formation, whereby neuronal activity into reticular formation is reduced without affecting its intrinsic ability to activate the cerebral cortex. Mesoridazine shows a moderate adrenergic blocking activity in vitro and in vivo and antagonizes 5-hydroxytryptamine in vivo.