(S)-Terazosin is an active S-enantiomer of Terazosin. (S)-Terazosin is a potent and high-affinity α-adrenoceptor antagonist with Ki values of 3.91 nM, 0.79 nM and 1.16 nM for α1a, α1b and α1d-adrenoceptor, respectively. (S)-Terazosin also has high-affinity for α2a, α2B and α2c-adrenoceptor with Ki values of 729 nM, 3.5 nM and 46.4 nM, respectively[1].
[1]. Hancock AA, et al. Actions of terazosin and its enantiomers at subtypes of alpha 1- and alpha 2-adrenoceptors in vitro. J Recept Signal Transduct Res. 1995 Sep-Dec;15(7-8):863-85.