Terazosin DESCRIPTION NewsLinks Terazosin hydrochloride, an alpha-1-selective adrenoceptor blocking agent, is a quinazoline derivative represented by the following chemical name and structural formula: (RS)-Piperazine, 1-(4-amino-6, 7-dimethoxy-2-quinazolinyl) -4- -, monohydrochloride, dihydrate. Terazosin hydrochloride is a white, crystalline substance, freely soluble in water and isotonic ...