|Other names||R-55667; R55667; Tiserton|
|CompTox Dashboard (EPA)|
|Chemical and physical data|
|Molar mass||477.57 g·mol−1|
|3D model (JSmol)|
|(what is this?)|
Ritanserin, also known by its developmental code name R-55667, is a serotonin antagonist medication described as an anxiolytic, antidepressant, antiparkinsonian agent, and antihypertensive agent. It was never marketed for medical use due to safety problems but has been used in scientific research to study the serotonin system.
Ritanserin acts as a selective 5-HT2A (Ki = 0.45 nM) and 5-HT2C receptor (Ki = 0.71 nM) antagonist. It has relatively low affinity for the H1, D2, α1-adrenergic, and α2-adrenergic receptors (39-, 77-, 107-, and 166-fold lower relative to 5-HT2A, respectively). The affinity of ritanserin for the 5-HT1A receptor is less than 1 μM. In addition to its affinity for the 5-HT2A and 5-HT2C receptors, ritanserin also binds to and antagonizes the 5-HT1D, 5-HT2B, 5-HT5A, 5-HT6, and 5-HT7 receptors.
The atypical antipsychotic risperidone was developed from ritanserin.
Ritanserin is the generic name of the drug and its INN, USAN, and BAN. It is also known by its developmental code name R-55667.
Ritanserin was never approved or marketed for medical use.
Ritanserin was tested in clinical trials for depression, anxiety, schizophrenia, and migraine. It was also found to improve sleep in human volunteers.