Ziprasidone's antipsychotic activity is likely due to a combination of its antagonistic function at D2 receptors in the mesolimbic pathways and at 5HT2A receptors in the frontal cortex. Alleviation of positive symptoms is due to antagonism at D2 receptors while relief of negative symptoms are due to 5HT2A antagonism.
Ziprasidone is a psychotropic agent belonging to the chemical class of benzisoxazole derivatives and is indicated for the treatment of schizophrenia. Ziprasidone is a selective monoaminergic antagonist with high affinity for the serotonin Type 2 (5HT2), dopamine Type 2 (D2), 1 and 2 adrenergic, and H1 histaminergic receptors. Ziprasidone acts as an antagonist at other receptors, but with lower potency. Antagonism at receptors other than dopamine and 5HT2 with similar receptor affinities may explain some of the other therapeutic and side effects of Ziprasidone. Ziprasidone's antagonism of muscarinic M1-5 receptors may explain its anticholinergic effects. Ziprasidone's antagonism of histamine H1 receptors may explain the somnolence observed with this drug. Ziprasidone's antagonism of adrenergic a1 receptors may explain the orthostatic hypotension observed with this drug. Ziprasidone functions as an antagonist at the Dopamine D2 , 5HT-2A , and 5HT-1D receptors, and as an agonist at the 5HT-1A receptor. Ziprasidone also inhibits synaptic reuptake of serotonin and norepinephrine.