The international terazosin trial: a multicentre study of the long-term efficacy and safety of terazosin in the treatment of benign prostatic hyperplasia. The ITT Group

Eur Urol. 1996;30(3):369-76. doi: 10.1159/000474198.


Objective: To evaluate the long-term efficacy and safety of terazosin in the treatment of benign prostatic hyperplasia (BPH).

Methods: Thirty-three sites in 13 countries enrolled men with BPH who had an International Prostate Symptom Score (IPSS) > or = 12 [corrected]. After a 2-week, no-treatment lead-in period and a 26-week, single-blind treatment period, patients responding to terazosin were randomly assigned to receive either terazosin or placebo for a 24-week, double-blind withdrawal period.

Results: Of the initial 427 patients enrolled, 378 were evaluable, 273 of whom completed the single-blind period, of which 186 patients were randomized. During the single-blind treatment period, IPSS, quality-of-life score (QOL), peak flow rate (PFR), and nocturia score (NOC) improved significantly (p < or = 0.05). During the double-blind withdrawal period, IPSS, QOL, PFR, and NOC deteriorated significantly in the placebo group compared with the terazosin group. The most common adverse event resulting in premature termination from the study was dizziness. There were no clinically important mean reductions in diastolic blood pressure (DBP) for patients normotensive at baseline. Terazosin significantly reduced mean DBP in hypertensive patients during the single-blind period and maintained the reduction during the double-blind period.

Conclusion: Treatment with terazosin has a beneficial effect on BPH, continuing for at least 12 months, and can be safely considered for medium- to long-term use in those who benefit.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic alpha-Antagonists / adverse effects
  • Adrenergic alpha-Antagonists / therapeutic use*
  • Adult
  • Aged
  • Aged, 80 and over
  • Double-Blind Method
  • Humans
  • Male
  • Middle Aged
  • Prazosin / adverse effects
  • Prazosin / analogs & derivatives*
  • Prazosin / therapeutic use
  • Prostatic Hyperplasia / drug therapy*
  • Quality of Life
  • Safety
  • Single-Blind Method


  • Adrenergic alpha-Antagonists
  • Terazosin
  • Prazosin