Tamsulosin is a drug that is used in the treatment of urinary obstruction that is caused by prostate enlargement or benign prostatic hyperplasia. It is several times stronger in action that prazocin and phentolamine in terms of alpha-blockage activities. Tamsulosin is a selective blocker of alpha-1 receptors in the prostate, which further brings about relaxation of the prostate tissues and improved urinary flow.