• A one-to-one relationship between clinical antipsychotic potency and pharmacologic dopaminergic antagonism is implicit in the dopamine hypothesis of neuroleptic action. Thiethylperazine maleate, a classical antiemetic phenothiazine, displays dopaminergic antagonism in behavioral, neurochemical, and neuroendocrine systems, but is paradoxical insofar as it is thought not to possess clinical neuroleptic activity. In three tests of dopaminergic antagonism-elevation of levels of CSF homovanillic acid in monkeys, striatal dihydroxyphenylacetic acid in rats, and prolactin in man-as well as in a clinical trial of neuroleptic efficacy in schizophrenics, thiethylperazine was fully active and approximately three times as potent as chlorpromazine. Differences in efficacy between this and earlier clinical studies can be accounted for on the basis of dosage.
Rotrosen J, Angrist BM, Gershon S, Aronson M, Gruen P, Sachar EJ, Denning RK, Matthysse S, Stanley M, Wilk S. ThiethylperazineClinical Antipsychotic Efficacy and Correlation With Potency in Predictive Systems. Arch Gen Psychiatry. 1978;35(9):1112-1118. doi:10.1001/archpsyc.1978.01770330086008