ALPHA-BLOCKADE THERAPY FOR BENIGN PROSTATIC HYPERPLASIA - FROM A NONSELECTIVE TO A MORE SELECTIVE ALPHA(1A)-ADRENERGIC ANTAGONIST

Benign prostatic hyperplasia (BPH) is very common in older men, causin g symptoms that can markedly impair quality of life. Surgical treatmen t, typically transurethral resection of the prostate (TURP), is highly effective but can be costly and is associated with the risk for signi ficant morbidity. Medical treatments for BPH are targeted toward reduc ing bladder outlet obstruction either by androgen blockade to reduce p rostatic volume or alpha-adrenergic blockade to relax the smooth muscl e tone of the prostate. In recent years, understanding of the sympathe tic innervation of the prostate has improved. This has been paralleled by the development of alpha-adrenergic blocking agents, from nonselec tive alpha-antagonists, to selective alpha(1)-antagonists, to the more selective alpha(1A)-antagonists. It is anticipated that more specific agents will optimize the therapeutic effectiveness of alpha-adrenergi c blockade in the prostate while reducing the side effects associated with alpha-adrenergic blockade in other areas of the body, such as the vascular system. This article reviews the evolution of alpha-blockade therapy in management of BPH, focusing on tamsulosin, an agent target ed toward the alpha(1A)-adrenoceptor that predominates in the prostate . Clinical trials in Europe and the United States have provided eviden ce that tamsulosin is effective at doses of 0.4 and 0.8 mg/day. At bot h doses, tamsulosin is associated with significant improvements in the American Urological Association symptom score and the mean and peak u rinary flow rates as compared with placebo. This once-daily alpha(1A)- adrenergic antagonist is well-tolerated, with a minimal potential for the side effects associated with alpha(1)-blocker therapy. (C) 1998, E lsevier Science Inc. All rights reserved.