Tiodazosin is a potent competitive postsynaptic alpha adrenergic receptor antagonist.
Tiodazosin is a potent competitive postsynaptic alpha adrenergic receptor antagonist. In the mesenteric artery, Tiodazosin produces a parallel shift to the right in the concentration response curves to norepinephrine. A Schild plot constructed from two concentrations of Tiodazosin results in a pA2 value of 8.66 and a slope equal to -0.99. Tiodazosin inhibits contraction to norepinephrine in the portal vein and the inhibition results in a nonparallel inhibition of the norepinephrine concentration-response curve with a marked depression of maximal norepinephrine response[1].
[1]. Cohen ML, et al. In vitro comparison of the pre- and postsynaptic alpha adrenergic receptor blocking properties of prazosin and tiodazosin (BL5111).