Finasteride, a 5α-reductase inhibitor, has been shown to have beneficial effects in the treatment of benign prostatic hyperplasia. The long-term safety and efficacy of finasteride in the treatment of benign prostatic hyperplasia was assessed.
In two multicenter, double-blind, placebo-controlled studies (North American and international), patients with symptomatic benign prostatic hyperplasia were randomly assigned to receive finasteride, 1 or 5 mg, or placebo for 1 year followed by an open-extension study in which all patients were treated with finasteride, 5 mg, regardless of original therapy. Men aged 40 to 80 years, in good physical and mental health, were eligible to enter the study. All patients were to have a maximum urinary flow rate of 15 mL/s or less with a voided volume of 150 mL or more, an enlarged prostate, and symptoms of urinary obstruction. Patients with a prostate-specific antigen level of 40 mg/mL or more or any finding suggestive of prostate cancer were excluded.
Two hundred ninety-eight patients received finasteride, 5 mg, continuously for 24 months. At the end of 24 months of finasteride therapy, the median prostate volume was reduced by 25%, and 60% of patients had a 20% or greater reduction in prostate volume. Maximum urinary flow rate was improved by at least 2 mL/s, and symptoms were improved by approximately 3.5 points. Decreased libido and ejaculation disorders were the only drug-related adverse experiences reported in more than 1% of patients.
These studies support the long-term safety and tolerability of finasteride, while demonstrating its continuing clinical efficacy in the treatment of patients with symptomatic benign prostatic hyperplasia.(Arch Intern Med. 1994;154:83-88)