Flesinoxan is a new heterobicyclic-aryl-piperazine, chemically different from buspirone-like compounds. In vitro, flesinoxan is a highly selective 5-HT1A receptor agonist and has much weaker affinity for α1-adrenergic, dopamine 2, and dopamine 3 receptors compared with buspirone (Duphar, unpublished data). The highest density of flesinoxan binding sites in brain is observed in the hippocampus, dentate gyrus, lateral septum, and entorrhinal cortex (Duphar, unpublished data). In several animal paradigms of anxiety, flesinoxan is more potent in reducing anxiety than are buspirone and ipsapirone (Duphar, unpublished data). Phase II studies have shown that flesinoxan is clearly effective in relieving symptoms of generalized anxiety disorder and better than placebo (Duphar, unpublished data). Generally, a low dose (0.4 mg) of flesinoxan is well tolerated. Higher doses (4.0 mg) are associated with treatment emergent adverse events, such as nausea, vomiting, nervousness, dizziness, and headache (Duphar, unpublished data). Currently, flesinoxan is under clinical development as a treatment both for generalized anxiety disorder and for major depressive disorder.
Flesinoxan is a hypotensive agent and a potent, high affinity and selective 5-hydroxytryptamine1A (5-HT1A) receptor agonist with an EC50 value of 24 nM. Flesinoxan also has effective anxiolytic/antidepressant effects.
