The Efficacy of Terazosin in the Treatment of Benign Prostatic Hyperplasia: A Randomized, Placebo-controlled Double Blind Study

Lee, Sang Eun; Son, Hwancheol; Lee, Jin Haeng; Kim, Hyeon Hoe; Lee, Chongwook

Abstract

Since it has shown that the smooth muscle is the dominant cellular constituent of the hyperplastic prostate and outlet obstruction in benign prostatic hyperplasia (BPH) is mediated by sympathetic nerve system via prostatic smooth muscle alpha 1 receptor, various kinds of alpha blocker have been tried in the treatment of BPH with moderate effectiveness. From May 1994 to December, 1994, a randomized placebo-controlled double blind study of long-acting selective alpha 1 blocker terazosin was undertaken to evaluate short-term effects of pharmacotherapy for BPK Of 80 patients with symptomatic BPH who were randomized to receive placebo or terazosin, 42 completed the study. At baseline, the irritative, obstructive and total symptom score (mean+/-SD) were 8.4+/-3.3, 11.8+/-4.9, 20.2+/-7.6 in placebo group and 8.3+/-4.3, 12.1 +4.6, 20.4 +7.3 in terazosin group and the peak and mean urinary flow rate (ml/ sec) were 10.7+/-2.6 and 5.5+/-2.0 in placebo group and 9.8+/-3.6 and 5.1+/-2.1 in terazosin group. After 28 days trial, the irritative, obstructive and total symptom score (mean+/-SD) were 7.4+/-3.8, 9.3+/-5.6, 16.8+/-9.2 in placebo group and 5.2+/-3.6, 6.2+/-4.0,11.4+/-6.6 in terazosin group(p<0.05, p<0.05 and p<0.01) and the peak and mean urinary flow rate (ml/sec) were 11.1+/-5.1 and 5.8+/-3.1 in placebo group and 14.7+/-6.4, 8.0+/-3.9 in terazosin group. (p<0.01 and p<0.01) At least 30% improvement in total symptom score and peak flow rate were observed in 67% (14/21) and 76% (16/21) of patients respectively in terazosin group. The common side effects were mild dizziness in 5(22%) in terazosin group and 1(5%) in placebo group but premature termination was observed in only 2(9%) patients in terazosin group and 1(5%) in placebo group. The mean change in baseline systolic pressure was 2mmHg for normotensive group and 19mmHg for hypertensive group. In conclusion, this study showed beneficial short term result for the safety and efficacy of long acting selective alpha 1 blocker terazosin in the management of symptoms of BPH However, the durability of the safety and efficacy of terazosin needs to be evaluated for longer periods.