We assessed the long-term safety and efficacy of finasteride, an orally active 5 alpha-reductase inhibitor, in 2 previously reported groups of patients with symptomatic benign prostatic hyperplasia (BPH). Prostate volume was measured by magnetic resonance imaging, and the maximum urinary flow rate was assessed noninvasively. Symptoms were scored utilizing a patient self-administered symptom score questionnaire. Total symptom scores ranged from 0 (or asymptomatic) to 35 (severely symptomatic). After an initial double-blind period, the patients in study 1 were treated with 10 mg finasteride for 1 year and then switched to 5 mg finasteride for an additional 4 years, whereas patients in study 2 were treated with 5 mg finasteride for the entire 5 years. A total of 190 patients were randomized in the double-blind studies, 156 entered year 1 of the open extension and 70 patients completed 5 years of finasteride therapy. In both studies prostate volume was reduced from baseline by 30%, dihydrotestosterone was reduced by 72%, and the maximum urinary flow rate improved by approximately 1.5 ml/s. Prostate-specific antigen was decreased by approximately 50%. Finasteride was well tolerated; approximately 10% of patients reported sexual adverse experiences during the 5-year study period, which were considered drug related by the investigators. The incidence in reporting sexual adverse experiences did not increase with the increased duration of treatment: findings consistent with previous reports. In summary treatment of BPH with finasteride for 5 years inhibits the progression of the disease with an excellent safety profile and represents a low-risk medical option for the treatment of symptomatic BPH.
