Terazosin hydrochloride dihydrate (Heitrin dihydrate) is a selective α1-adrenoceptor antagonist, used for treatment of symptoms of an enlarged prostate (BPH).

Terazosin results in a significant loss of cell viability, via induction of apoptosis in a dose-dependent manner in prostate cancer cells. Terazosin suppresses prostate growth potentially via α 1-adrenoceptor-independent actions gains further support from another study documenting that Doxazosin inhibits proliferation of human vascular smooth muscle cells independently of an antagonistic effect on α1-adrenoceptor. [1] Terazosin blocks HERG currents in Xenopus oocytes with IC50 of 113.2 mM, while Terazosin blocks HERG channel inhibition in human HEK 293 cells with IC50 of 17.7 mM. [2] Terazosin or genistein treatment inhibits the growth of DU-145 cells in a dose-dependent manner, whereas has no effect on normal prostate epithelial cells. Terazosin results in the genistein-induced arrest of DU-145 cells in G2/M phase being overridden and an increase in apoptotic cells, as evidenced by procaspase-3 activation and PARP cleavage. [3] Terazosin induces cytotoxicity in PC-3 and human benign prostatic cells with an IC50 of more than 100 mM. [4]

Terazosin significantly inhibits vascular endothelial growth factor induced angiogenesis in nude mice with an IC50 of 7.9 mM, showing that it has a more potent anti-angiogenic than cytotoxic effect. Terazosin also effectively inhibits vascular endothelial growth factor induced proliferation and tube formation in cultured human umbilical vein endothelial cells (IC50 9.9 and 6.8 mM, respectively). [4]