Pharmacological treatment of benign prostatic hyperplasia with finasteride: a clinical review

Finasteride acts by blocking the conversion of testosterone to 5 alpha-dihydrotestosterone, the active androgen metabolite in the human prostate. In large, double-blind, placebo-controlled phase III studies recruiting over 1600 patients, it was shown that the administration of Finasteride, either 5 or 1 mg a day, reduced the size of the prostate by a mean of 22%, following 6 months of therapy. Despite this reduction in prostate size, urinary flow rate only improved by a mean of 1.7 ml per second and symptom score improved only marginally, but statistically significantly different from placebo. Long-term results in small series of patients have indicated a further improvement beyond 1 year. After 3 years flow was improved by 60%. The future role for Finasteride therapy is emerging, but it appears as if patients with mild to moderate symptoms would be a group who could benefit the most. Whether or not Finasteride can stop the long-term natural course of benign prostatic hyperplasia has still to be demonstrated.