Blonanserin

Blonanserin, sold under the brand name Lonasen, is a relatively new atypical antipsychotic (approved by PMDA in January 2008) commercialized by Dainippon Sumitomo Pharma in Japan and Korea for the treatment of schizophrenia. Relative to many other antipsychotics, blonanserin has an improved tolerability profile, lacking side effects such as extrapyramidal symptoms, excessive sedation, or hypotension. As with many second-generation (atypical) antipsychotics it is significantly more efficacious in the treatment of the negative symptoms of schizophrenia compared to first-generation (typical) antipsychotics such as haloperidol. Blonanserin is used to treat schizophrenia in Japan and South Korea but not in the US. As with many of the atypical antipsychotics, blonanserin can elicit cardio metabolic risks. While the side effects of blonanserin – such as weight gain, cholesterol and triglyceride levels, glucose levels and other blood lipid levels – do not differ greatly from other atypical antipsychotics, the specificity of blonanserin appears to elicit milder side effects, with less weight gain in particular. Blonanserin acts as a mixed 5-HT2A (Ki = 0.812 nM) and D2 receptor (Ki = 0.142 nM) antagonist and also exerts some blockade of α1-adrenergic receptors (Ki = 26.7 nM). Blonanserin also shows significant affinity for the D3 receptor (Ki = 0.494 nM). It lacks significant affinity for numerous other sites including the 5-HT1A, 5-HT3, D1, α2-adrenergic, β-adrenergic, H1, and mACh receptors and the monoamine transporters, though it does possess low affinity for the sigma receptor (IC50 = 286 nM). Blonanserin has a relatively high affinity towards the 5-HT6 receptor perhaps underpinning its recently unveiled efficacy in treating the cognitive symptoms of schizophrenia.