Objective: To assess the long-term safety and efficacy of finasteride in the treatment of symptomatic benign prostatic hyperplasia in patients treated with finasteride 5 mg for thirty-six months.
Methods: Two large multicenter studies were used. Patients were randomly assigned to treatment with finasteride, 1 or 5 mg, or placebo for twelve months. After completing twelve months of therapy, patients were invited to enter an open extension to the study in which all patients received finasteride 5 mg. Urinary symptoms, urinary flow rate, prostate volume, and serum concentrations of prostate-specific antigen and dihydrotestosterone were measured periodically during the study.
Results: After thirty-six months of treatment with finasteride 5 mg, prostate volume was reduced from baseline by approximately 27 percent, maximum urinary flow rate improved by approximately 2.3 mL/second, and symptom scores improved by 3.6 points. Forty-two percent of patients had a 30 percent or greater decrease in prostate volume, 40 percent of patients showed an increase of 3 mL/second or more in maximum urinary flow rate, and 48 percent of patients experienced a 50 percent or greater improvement in symptom scores. Finasteride was well tolerated and there was no evidence of increased adverse experiences with increased duration of treatment.
Conclusions: The excellent safety profile and sustained clinical efficacy, over thirty-six months, of daily treatment with finasteride 5 mg recommend finasteride as a low-risk medical option for the treatment of symptomatic benign prostatic hyperplasia.