Efficacy and safety of finasteride therapy for benign prostatic hyperplasia: results of a 2-year randomized controlled trial (the PROSPECT study). PROscar Safety Plus Efficacy Canadian Two year Study

CMAJ. 1996 Nov 1;155(9):1251-9.


Objective: To evaluate the efficacy and safety of 2 years' treatment of moderate benign prostatic hyperplasia (BPH) with finasteride.

Design: Double-blind, parallel-group, placebo-controlled, multicentre, prospective randomized study.

Setting: Outpatient care in 28 centres across Canada.

Participants: Men aged 45 to 80, in good health, with moderate BPH and no evidence of prostate cancer. A total of 613 men were entered into the study; 472 completed the 2 years of treatment.

Intervention: After 1 month of receiving a placebo (run-in period), patients were given either finasteride (5 mg/d) or a placebo for 2 years.

Efficacy: changes from baseline in BPH symptom scores, maximum urinary flow rates and prostate volume.

Safety: onset, course and resolution of all adverse events during the treatment period.

Results: In the efficacy analyses the mean BPH symptom scores decreased 2.1 points (from 15.8 to 13.7) in the finasteride group, as compared with a decrease of 0.7 points (from 16.6 to 15.9) in the placebo group (P < or = 0.01). The maximum urinary flow rate increased by a mean of 1.4 mL/s (from 11.1 to 12.5 mL/s) in the finasteride group, as compared with an increase of 0.3 mL/s (from 10.9 to 11.2 mL/s) in the placebo group (p < or = 0.01). The mean prostate volume decreased by 21% (from a mean volume of 44.1 cm3 at baseline) in the treatment group; it increased by 8.4% (from a mean volume of 45.8 cm3 at baseline) in the placebo group (p < or = 0.01). In the safety analysis, the proportion of patients who experienced any adverse event was similar in the two groups (81.0% in the treatment group and 81.2% in the placebo group). However, the incidence of adverse events related to sexual dysfunction were significantly higher in the finasteride group than in the placebo group (ejaculation disorder 7.7% v. 1.7% and impotence 15.8% v. 6.3%; p < or = 0.01 for both parameters).

Conclusion: Finasteride is a well-tolerated and effective alternative to watchful waiting in the treatment of moderate BPH.

Publication types

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

MeSH terms

  • Aged
  • Aged, 80 and over
  • Canada
  • Double-Blind Method
  • Enzyme Inhibitors / adverse effects
  • Enzyme Inhibitors / therapeutic use*
  • Finasteride / adverse effects
  • Finasteride / therapeutic use*
  • Humans
  • Male
  • Middle Aged
  • Prospective Studies
  • Prostatic Hyperplasia / drug therapy*
  • Safety
  • Urination / drug effects


  • Enzyme Inhibitors
  • Finasteride