[The effects of dutasteride on voiding and storage symptoms in men with benign prostatic hyperplasia]

We investigated the effects of dutasteride on voiding and storage symptoms by a post-hoc analysis from two randomized, placebo-controlled, parallel-group studies (Japanese phase II study and phase III study) which assessed the efficacy and safety of dutasteride in Japanese men with benign prostatic hyperplasia (BPH). Men aged 50 years and older, with a prostate volume of 30 cc or greater, an International Prostate Symptom Score (IPSS) of 8 or higher and maximal urinary flow rate of 15 ml/sec or lower were randomized to placebo or dutasteride groups. The number of subjects for the placebo and dutasteride groups was respectively 72 and 72 in the phase II study, and 185 and 193 in the phase III study. Questions 1, 3, 5 and 6 of IPSS were related to voiding symptoms, and Questions 2, 4 and 7 were related to storage symptoms. Changes between pre- and post-treatments were evaluated. In the phase II study, dutasteride significantly improved voiding symptoms and numerically improved storage symptoms compared with the placebo at week 24. In the phase III study, dutasteride significantly improved voiding and storage symptoms compared with the placebo after 52 weeks. These consistent results suggest that dutasteride is effective for both voiding and storage symptoms in Japanese men with BPH.