Comparing the side effect profile of the atypical antipsychotics.

Typical antipsychotics exert their effect by blocking post-synaptic dopaminergic receptors; blockade of the mesolimbic and mesocortical pathways are therapeutic and help reduce positive psychotic symptoms but blockade of the nigro-striatal pathway produces extrapyramidal side effects (EPSE). Post clozapine, the Food and Drug Administration (FDA) has approved the use of four newer atypical antipsychotics; risperidone, olanzapine, quetiapine and ziprasidone for the treatment of schizophrenia. Because of their dual serotonin and dopamine receptor blocking abilities, atypical antipsychotics have greater efficacy (especially for negative symptoms) and fewer EPSE when compared to the typical antipsychotics. Given the lack of studies directly comparing these agents, we used the Physician Desk Reference (PDR) to calculate the treatment emergent placebo adjusted side effects for these atypical antipsychotics. The results are then presented in an easy to read table. To the best of our knowledge, this is the first comparison study involving these four newer antipsychotic agents.