Objective: Dutasteride, a double inhibitor of 5α - reductase isoenzym types 1 and 2, would reduce angiogenesis associated with benign prostatic hyperplasia (BPH), thereby decreasing perioperative bleeding during transurethral resection of the prostate (TURP). Methods: We try to evaluate the blood loss related to TURP for BPH in patients over the age of 50 years with a prostatic volume greater than 30 cm3 and PSA less than 4 ng / ml.