Risperidone Not long after clozapine resurfaced, risperidone was developed following the observation that ritanserin (a serotonin 5-HT2A,2B,6,7 receptor antagonist) improved negative symptoms and reduced the incidence of EPS when added to conventional antipsychotics . Risperidone blocks both 5-HT2 and D2 receptors, with a 20-fold higher binding affinity for 5-HT2 over D2. Several short term studies in patients with chronic schizophrenia have shown equal and greater improvement in positive and negative symptoms, respectively, compared with conventional agents. However, the advantage regarding negative symptoms is not consistent among trials and was not demonstrable in a recent meta-analysis. buy ortho tri-cyclen online
Risperidone has been compared with olanzapine in two randomized, controlled trials. The first is outlined in the following olanzapine section, and the details of the second have yet to be published. Bondolfi et al compared risperidone with clozapine in subjects with treatment-resistant schizophrenia and found similar efficacy, albeit in a small (n=86) and brief trial (eight weeks). Treatment resistance was more loosely defined in this trial compared with the criteria of Kane et al. Included were patients failing to respond to any two conventional neuroleptic trials of four weeks or longer in duration.