Ziprasidone's efficacy in treating the positive symptoms of schizophrenia is believed to be mediated primarily via antagonism of the dopamine receptors, specifically D2. Blockade of the 5-HT2A receptor may also play a role in its effectiveness against positive symptoms, though the significance of this property in antipsychotic drugs is still debated among researchers.
Blockade of 5-HT2A and 5-HT2C and activation of 5-HT1A as well as inhibition of the re-uptake of serotonin and norepinephrine may all contribute to its ability to alleviate negative symptoms.[13] The relatively weak antagonistic actions of ziprasidone on the α1-adrenergic and H1 receptors likely in part explain some of its side effects, such as sedation and orthostatic hypotension. Unlike many other antipsychotics, ziprasidone has no significant affinity for the mACh receptors, and as such lacks any anticholinergic side effects