INTRODUCTION AND OBJECTIVES:We have evaluated silodosin as a new treatment option for premature ejaculation (PE). Silodosin, a highly selective a1A-adrenoceptor antagonist, demonstrates excellent clinical efficacy for LUTS and has a strong suppressive action on ejaculation. This suppressive action is able to be applicable to treatment for PE. Our previous study demonstrated favorable effects on alleviation of PE symptoms (Sato et al. Int J Urol 2012). In this study, We compared efficacy of silodosin and naftopidil that has the weakest suppressive actions among a1 blockers as a control drug on PE.METHODS: Twenty seven patients who suffered with PE were enrolled in this study. PE was defined as IELT is about 3 minutes or less and patients felt the inability to delay ejaculation and negative personal consequences due to the ISSM recommendation in 2014. Subjects had a mean age of 50.6years, reported having had PE for an average of 6.0 years. Eleven patients (41%) suffered with ED and had received treatment by phosphodiesterase type 5 inhibitors before starting treatment for PE. Patients administrated silodosin 4 mg or naftopidil 25 mg 1 hours before intercourse in turn at least 3 times each. Intravaginal ejaculatory latency time (IELT), premature ejaculation profile item, clinical global impression change in PE, and systemic adverse events were evaluated. IELT measured using a watch by the patient. RESULTS: 1) Mean IELTs were 1.9, 4.1 and 7.6 minutes at baseline and with control and with silodosin, respectively. Silodosin significantly prolonged IELT compared to that at baseline and with control drug (p<0.01 table1). 2) Efficacy: Ten patients (37%) reported improvement for own PE problems under silodosin administration compared to baseline condition by the CGCI. Silodosin showed significantly higher efficacy rate compared to that with control drug (p¼0.003). 3) Silodosin significantly improved ejaculation control and satisfaction of sexual intercourse compared to those at base line and with control (p <0.01). 4) Reduced semen volume and orgasm: Twelve patients (46%) experienced significant reduction of semen volume on silodosin administration. This rate was significantly higher than with control (p¼0.017). Six patients (23%) considered reduced semen volume with silodosin as a significant problem. However, four patients achieved adequate IELT and normal ejaculation with satisfied orgasm by dose reduction (2mg-silodosn). 4) No systemic adverse effects were reported with silodosin.CONCLUSIONS: Silodosin significantly improved PE related problems than control drug. Reduced semen volume with silodosin was able to manage by dose reduction. Our current results confirmed the potential of silodosin as a new treatment option for PE. INTRODUCTION AND OBJECTIVES: Premature ejaculation(PE) is one of the most common male sexual disorders and has been estimated to occur in 20% to 40% of men. Selective serotonin reuptake inhibitors (SSRIs) commonly used in treatment of PE. However, the use of sildenafil combined with dapoxetine to ...