alpha1-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. alpha1-Adrenoceptors (alpha1ARs) maintain prostate smooth muscle tone; hence, alpha1-antagonists (blockers) relax prostate smooth muscle and decrease urethral resistance, ultimately leading to relief of LUTS. This review focuses on alpha1AR 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 alpha1AR blockers for LUTS. Benefits and adverse effects of clinically available alpha1AR antagonists are reviewed, followed by recent information on interactions between alpha1AR subtype antagonists and type 5 phosphodiesterase inhibitors used for impotence. alpha1-Adrenoceptor antagonists have become the mainstay of therapy for LUTS; knowledge about specific alpha1AR subtypes should facilitate rational choice of alpha1AR blocker therapy by clinicians.