α1-adrenoceptor subtype selectivity and lower urinary tract symptoms

Benign prostatic hyperplasia is a common cause of urinary flow obstruction in aging men and may lead to lower urinary tract symptoms (LUTS). Benign prostatic hyperplasia has 2 physiological components: a static component related to increased prostate size and a dynamic component related to increased prostate smooth muscle tone. alpha(1)-Adrenoceptors (alpha(1)ARs) maintain prostate smooth muscle tone; hence, alpha(1)-antagonists (blockers) relax prostate smooth muscle and decrease urethral resistance, ultimately leading to relief of LUTS. This review focuses on alpha(1)AR subtypes and their location in lower urinary tract tissues involved in LUTS (prostate, bladder, spinal cord); it also summarizes major clinical trials published to date on the efficacy of alpha(1)AR blockers for LUTS. Benefits and adverse effects of clinically available alpha(1)AR antagonists are reviewed, followed by recent information on Interactions between alpha(1)AR subtype antagonists and type 5 phosphodiesterase inhibitors used for impotence. alpha(1)-Adrenoceptor antagonists have become the mainstay of therapy for LUTS; knowledge about specific alpha(1)AR subtypes should facilitate rational choice of alpha(1)AR blocker therapy by clinicians.