Non-inferiority of silodosin to tamsulosin in treating patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH)

Study Type - Therapy (RCT) Level of Evidence 1b What's known on the subject? and What does the study add? Silodosin administered by 4 mg twice daily is as effective as tamsulosin 0.2 mg daily in treating patients with LUTS associated with BPH. Relative to tamsulosin, silodosin has less cardiovascular side effects as judged by the minimal changes of blood pressure and pulse rats after treatment. OBJECTIVE • To test the hypothesis that the efficacy of silodosin would not be inferior to tamsulosin in treating patients with lower urinary tract symptoms associated with benign prostate hyperplasia (BPH). PATIENTS AND METHODS • At nine medical centres, 209 patients with an International Prostate Symptom Score (IPSS) of ≥13 were randomized to silodosin (4 mg twice daily) or tamsulosin (0.2 mg once daily) for 12 weeks. • The primary efficacy measure was the mean change from baseline to endpoint in IPSS. • The non-inferiority margin of the IPSS change was set at 1.0. • Secondary efficacy measures included change in maximal urinary flow rate (Q _max) and health-related quality of life (HRQL) score. RESULTS • Of the 170 (81.3%) patients who completed the study, 86.2% in the silodosin group vs 81.9% in the tamsulosin group achieved a ≥25% decrease in IPSS (P= 0.53). • The mean difference (silodosin minus tamsulosin) in IPSS change from baseline was -0.60 (95% confidence interval -2.15, 0.95), inferring the non-inferiority of silodosin to tamsulosin. • The mean changes in the Q _max and HRQL score from baseline were comparable between the groups (both, P > 0.05). Although patients receiving silodosin had a significantly higher incidence of abnormal ejaculation (9.7% vs tamsulosin 1.0%, P= 0.009), only 1.9% discontinued treatment. • Tamsulosin treatment resulted in a significant reduction in mean systolic blood pressure (-4.2 mmHg, within-group P= 0.004) relative to the negligible change of silodosin (-0.1 mmHg, within-group P= 0.96) CONCLUSION • The trial shows the non-inferiority of silodosin 4 mg twice daily to tamsulosin 0.2 mg once daily in patients with symptoms of BPH.