One‐Year Experience in the Treatment of Benign Prostatic Hyperplasia with Finasteride

Abstract Finasteride (MK‐906) is a 5α‐reductase inhibitor that reduces circulating dihydrotestosterone (DHT) levels without lowering testosterone levels. The goal of this study was to evaluate the effects of long‐term (12 months) treatment with finasteride in 67 men with benign prostatic hyperplasia to determine if previously reported short‐term efficacy was maintained with chronic therapy. Treatment with 10 mg of finasteride resulted in a 78% to 80% reduction in DHT levels (P < 0.001) levels, and a small but significant increase in testosterone levels (P < 0.05) that were maintained over the 12‐month period. Significant reduction in prostate volume was observed after 6 months of treatment and maintained at month 12 (P < 0.05). In patients with baseline maximum flow rates ≤15 ml/second, maximum urinary flow significantly increased by a mean of 4 ml/second (P < 0.01), with at least a 3 ml/second improvement observed in up to 70% of the patients at month 12. These results indicate that finasteride can reduce prostate size and improve maximum urinary flow with no loss of efficacy after 1 year of treatment. It is concluded that finasteride has the potential to be an effective chronic therapy for benign prostatic hyperplasia.