Objectives. To evaluate the safety and efficacy of finasteride 5 mg during a 10-year period in men with enlarged prostates from a single center who participated in the double-blind and extension phases of the multicenter, Phase III, North American benign prostatic hyperplasia (BPH) trial. It is important that the long-term safety and efficacy of drugs intended for chronic administration in men with BPH be well understood. Methods. The Phase III North American BPH trial involved a 1-year, placebo-controlled, double-blind study, followed by a 5-year open extension with finasteride 5 mg/day. The trial enrolled men with symptomatic BPH, an enlarged prostate on digital rectal examination, and no evidence of prostate cancer. Of the 46 patients originally enrolled from our institution, 43 were randomized to receive finasteride or placebo, of whom 41 (95%) completed the double-blind study and entered the 5-year extension. Thirty (73%) of these 41 patients completed the 5-year extension. Patients continued to be followed up by their physicians for an additional 5 years, for a total follow-up of at least 10 years. Results. Twenty-four (56%) of the original 43 patients randomized to finasteride or placebo were judged as successfully treated during the 10-year finasteride follow-up (17 patients taking finasteride alone at 10 years and 7 patients who were taking finasteride alone when they discontinued during the 10-year follow-up for reasons not related to finasteride treatment). Altogether, 22 (51%) of the original 43 randomized patients continued finasteride treatment at 10 years (17 taking finasteride alone, 4 taking finasteride plus an alpha-blocker, and 1 taking finasteride for treatment of hematuria). Finasteride was well tolerated, with no new adverse experiences occurring with increasing duration of exposure to the drug. Conclusions. This long-term follow-up study has demonstrated that appropriately selected patients with symptomatic BPH and enlarged prostates are likely to have a long-term response to taking finasteride 5 mg daily.
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