 The primary experience in treating obstructive and irritative voiding symptoms is in men with benign prostatic hyperplasia BPH. In patients with moderate to severe voiding symptomatology, based in the American Urological Association AUA Symptom Score Index, medical treatment with alpha antagonists has become commonplace. The use of alpha antagonists is based upon the reduction of smooth muscle tone in both the prostate gland and urinary bladder neck by inhibition of alpha1 adrenoceptor, resulting in relaxation of bladder outlet obstruction and increased urinary flow. 