To investigate if short-term treatment with dutasteride ( 8 weeks ) before bipolar transurethral resection of the prostate ( B-TURP ) can reduce intraoperative bleeding , as dutasteride a dual 5-reductase inhibitor ( 5-ARI ) blocks the conversion of testosterone into its active form dihydrotestosterone ( DHT ) , and reduces prostate volume and prostate-specific antigen ( PSA ) levels , while increasing urinary flow rate .