Comparison of Silodosin versus Tadalafil in Patients with Lower Urinary Tract Symptoms Associated with Benign Prostatic Hyperplasia.

OBJECTIVES

To compare the efficacy and safety of silodosin versus tadalafil for treating lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH).

METHODS

After informed consent, patients with LUTS/BPH were randomized in a 1:1 ratio to receive silodosin 8 mg/day or tadalafil 5 mg/day for 8 weeks (Period 1). Patients treated with tadalafil entered an exploratory phase and received silodosin or tadalafil for another 8 weeks. The primary efficacy endpoint was the change in the total International Prostate Symptom Score (IPSS) with Period 1 treatment.

RESULTS

Both silodosin and tadalafil demonstrated statistically significant improvement in IPSS total symptom score, with a mean ± standard deviation change of -10.1 ± 6.4 (P < 0.0001) and -8.0 ± 6.3 (P < 0.0001), respectively. The former reduction was significantly greater than the latter (P = 0.0277). Adverse drug reactions occurred at a rate of 23.4% with silodosin and 8.4% with tadalafil. No serious adverse drug reactions were documented, suggesting that both drugs were well tolerated. Moreover, results of Period 2 showed that switching to silodosin from tadalafil achieved a faster onset of improvements in IPSS Quality of Life Index score and total Overactive Bladder Symptom Score.

CONCLUSIONS

Silodosin achieved significantly greater improvement than tadalafil, with a higher incidence of adverse drug reactions. The risk-benefit profiles obtained in this study will provide useful information for optimal pharmacological treatment of LUTS/BPH. Our results suggest that silodosin can be one of the first-line therapies for rapid and efficient relief in patients with LUTS/BPH.