Silodosin: treatment of the signs and symptoms of benign prostatic hyperplasia

Silodosin is an α-adrenoceptor antagonist with high selectivity for α(1A)- relative to α(1B)- adrenoceptors. In men aged >50 years with benign prostatic hyperplasia (BPH), silodosin 8 mg once daily, compared with placebo, was associated with a significantly more rapid and effective improvement in the total International Prostate Symptom Score (IPSS) and the storage and voiding IPSS subscores in three 12-week, phase III trials conducted in Europe and the US. In the European trial, silodosin was at least as effective as tamsulosin 0.4 mg once daily in improving the total IPSS. Silodosin was significantly more effective than placebo (all three phase III trials) and tamsulosin (European phase III trial) in simultaneously improving nocturia, frequency and incomplete emptying, according to a post hoc analysis. Long-term, open-label extension trials demonstrated that silodosin provided sustained relief of the signs and symptoms of BPH for up to 1 year. Silodosin was generally well tolerated, and was associated with minimal cardiovascular adverse effects. Abnormal ejaculation, a class effect of α(1A)-adrenoceptor antagonists, was the most common silodosin-associated adverse reaction, but resulted in treatment withdrawal of only a limited number of patients.