Placebo-controlled study of terazosin in the treatment of benign prostatic hyperplasia with 2-year follow-up.

This randomised, placebo-controlled, double-blind study was performed to evaluate the efficacy and safety of once-a-day terazosin (10 mg/d) in ambulatory patients (n = 57) with benign prostatic hyperplasia (BPH). After a 4-week placebo lead-in and a 24-week treatment period with terazosin (with both phases being single-blind), 30 patients who responded to terazosin were randomly assigned to either the terazosin or placebo treatment group for 12 weeks. During the single-blind treatment period, the peak urine flow rate increased 54% from a baseline average of 7.76 ml/s to 11.92 ml/s after terazosin administration; the mean flow rate increased 55% from a baseline of 4.90 ml/s to 7.59 ml/s; and the residual volume decreased 56% from 93.1 ml to 40.7 ml. The mean obstructive symptom score, irritative symptom score and physician global assessment score improved by 68%, 34% and 27%, respectively. All these changes were significant when compared with baseline values. During the double-blind period, the improvement in all the variables was sustained in the terazosin group but not in the placebo group. Peak and mean urinary flow rates, and physician assessment showed significant differences at the end of the double-blind period. Adverse events occurred only during the single-blind period. The most frequently experienced events were headache (n = 6), asthenia (n = 3) and hypotension (n = 3). A follow-up study that initially included 12 patients showed no significant loss of improvement in symptoms and no change in urodynamic parameters with the 5 mg terazosin dose at 1 year. At 2 years, the 9 remaining patients showed sustained improvement and no signs of tachyphylaxis.