NCIt definition : A synthetic piperazine derivative and an alpha-1 adrenergic receptor inhibitor used
primarily as an anti-hypertensive. Prazosin's effects are most pronounced in the large
resistance vessels (i.e. arterioles) and result in a decrease in total systemic vascular
resistance (SVR) without a rebound or reflex tachycardia. To a lesser extent, this
agent also decreases the tone of the bladder sphincter, thereby allowing the opening
of the bladder into the urethra and thus relieving the urinary conditions associated
with benign prostatic hypertrophy.;