A review of the clinical efficacy and safety of 5alpha-reductase inhibitors for the enlarged prostate

Clin Ther. 2007 Jan;29(1):17-25. doi: 10.1016/j.clinthera.2007.01.018.


Background: Enlargement of the prostate is common among aging men, with an incidence of 90% by the age of 85 years. It is a progressive condition, with growth in prostate size accompanied by lower urinary tract symptoms that can result in long-term complications (eg, acute urinary retention [AUR], need for enlarged prostate-related surgery). Current pharmacologic treatment options include alpha-blockers (alfuzosin, doxazosin, tamsulosin, and terazosin) and 5alpha-reductase inhibitors (5ARIs) (finasteride and dutasteride).

Objectives: This article reviews the natural history of enlarged prostate and the data supporting management of this condition with alpha-blocker and 5ARI therapy, either as monotherapy or combination therapy, for symptomatic relief and a reduction in long-term disease progression.

Methods: Pertinent English-language articles were identified through a search of MEDLINE (1966-week 2, May 2006) using such search terms as 5alpha-reductase inhibitor, alpha-blocker, benign prostatic hyperplasia, dutasteride, efficacy, enlarged prostate, finasteride, and safety.

Results: Clinical trials of alpha-blockers in men with enlarged prostate have reported improvements in total symptom scores of 10% to 20% compared with placebo; however, these agents were not shown to reduce the risk of long-term complications or disease progression. Studies of the 5ARIs have reported significant reductions compared with placebo in the relative risk for AUR and enlarged prostate-related surgery, slowing of disease progression, and relief of symptoms. In studies of dutasteride, improvements in symptom scores were greater after 4 years of therapy compared with 2 years (-6.4 vs -4.3 points, respectively) and flow rates were better (2.6 vs 2.3 mL/sec). Six-year data for finasteride showed maintenance of the decreased risk for AUR and enlarged prostate-related surgery. Use of combination therapy with an alpha-blocker and a 5ARI may be of benefit in patients who require immediate relief of symptoms, with discontinuation of the alpha-blocker after several months of therapy. 5ARIs were generally well tolerated, with sexual dysfunction the most frequently reported adverse effect, although in only a small proportion of men (1%-8%).

Conclusions: The use of 5ARI therapy is a rational approach to symptom management and prevention of long-term negative outcomes in men with enlarged prostates.V 3.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adrenergic alpha-Antagonists / adverse effects
  • Adrenergic alpha-Antagonists / therapeutic use*
  • Aged
  • Aged, 80 and over
  • Azasteroids / adverse effects
  • Azasteroids / therapeutic use
  • Drug Therapy, Combination
  • Dutasteride
  • Enzyme Inhibitors / adverse effects
  • Enzyme Inhibitors / therapeutic use*
  • Finasteride / adverse effects
  • Finasteride / therapeutic use
  • Humans
  • Male
  • Middle Aged
  • Prostatic Hyperplasia / complications
  • Prostatic Hyperplasia / drug therapy*
  • Prostatic Hyperplasia / epidemiology
  • Prostatic Hyperplasia / physiopathology
  • Randomized Controlled Trials as Topic


  • Adrenergic alpha-Antagonists
  • Azasteroids
  • Enzyme Inhibitors
  • Finasteride
  • Dutasteride