New clinical evidence of silodosin, an α(1A) selective adrenoceptor antagonist, in the treatment for lower urinary tract symptoms.

Lower urinary tract symptoms associated with benign prostatic hyperplasia are highly prevalent in older men. Pharmacological treatment is the first-line treatment for lower urinary tract symptoms associated with benign prostatic hyperplasia. The first choice in the pharmacological treatment for lower urinary tract symptoms associated with benign prostatic hyperplasia is the α(1) -adrenoceptor antagonists. Many α(1) -adrenoceptor antagonists are available in the world. Silodosin is an α(1) -adrenoceptor antagonist developed by Kissei Pharmaceutical, and has a specific selectivity for the α(1A-) adrenoceptor subtype. By antagonizing α(1A) -adrenoceptor in the prostate and urethra, silodosin causes smooth muscle relaxation in the lower urinary tract. As a result of the high affinity for the α(1A) -adrenoceptor than for the α(1B) -adrenoceptor, silodosin minimizes the propensity for blood pressure-related adverse effects caused by blockade of α(1B) -adrenoceptor. The efficacy and safety of silodosin for treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia was first reported by Japanese investigators in 2006. At present, silodosin is used in many countries. In the present review, we summarize the new clinical evidence for lower urinary tract symptoms associated with benign prostatic hyperplasia and introduce the data supporting the new clinical indications of silodosin.