Evaluation of silodosin in comparison to tamsulosin in benign prostatic hyperplasia: a randomized controlled trial

Benign prostatic hyperplasia (BPH) is the most common cause of lower urinary tract symptoms in elderly men. Selective alfa1-adrenergic antagonists are now first-line drugs in the medical management of BPH. We conducted a single-blind, parallel group, randomized, controlled trial to compare the effectiveness and safety of the new alfa1-blocker silodosin versus the established drug tamsulosin in symptomatic BPH.

Ambulatory male BPH patients, aged above 50 years, were recruited on the basis of International Prostate Symptom Score (IPSS). Subjects were randomized in 1:1 ratio to receive either tamsulosin 0.4 mg controlled release or silodosin 8 mg once daily after dinner for 12 weeks. Primary outcome measure was reduction in IPSS. Proportion of subjects who achieved IPSS <8, change in prostate size as assessed by ultrasonography and changes in peak urine flow rate and allied uroflowmetry parameters, were secondary effectiveness variables. Treatment emergent adverse events were recorded.

Data of 53 subjects - 26 on silodosin and 27 on tamsulosin were analyzed. Final IPSS at 12-week was significantly less than baseline for both groups. However, groups remained comparable in terms of IPSS at all visits. There was a significant impact on sexual function (assessed by IPSS sexual function score) in silodosin arm compared with tamsulosin. Prostate size and uroflowmetry parameters did not change. Both treatments were well-tolerated. Retrograde ejaculation was encountered only with silodosin and postural hypotension only with tamsulosin.

Silodosin is comparable to tamsulosin in the treatment of BPH in Indian men. However, retrograde ejaculation may be troublesome for sexually active patients.