5-alpha-reductase inhibitors (5ARI) for benign prostatic hyperplasia

Evidence Summaries

Level of Evidence = A
Finasteride and dutasteride reduce prostate volume, increase urinary flow and improve symptoms in benign prostatic hyperplasia.

A Cochrane review 1 on finasteride for benign prostatic hyperplasia included 23 studies with a total of 21,945 subjects. Finasteride consistently improved urinary symptom scores more than placebo in trials of > 1 year duration (4 studies), and significantly lowered the risk of BPH progression (acute urinary retention, risk of surgical intervention, ≥ 4 point increase in the AUASI/IPSS). There was an increased risk of ejaculation disorder, impotence, and lowered libido for finasteride versus placebo.

A systematic review 2 including 11 studies with a total of 13,822 subjects was abstracted in DARE. Reductions in prostate volume, increases in urinary flow rates and improvements in symptoms compared with placebo have been observed in trial of up to 4 years´ duration and in noncomparative extensions (up to 6 years). Results from the PLESS trial show finasteride to significantly reduce the risk of acute urinary retention and requirement for surgical intervention. Similar efficacy has been reported with the novel 5-ARI dutasteride which inhibits both subtype I and subtype II 5-alpha-reductase.


1. Tacklind J, Fink HA, Macdonald R, Rutks I, Wilt TJ. Finasteride for benign prostatic hyperplasia. Cochrane Database Syst Rev 2010;(10):CD006015.  [PMID:20927745]
2. Wilde MI, Goa KL. Finasteride: an update of its use in the management of symptomatic benign prostatic hyperplasia. Drugs 1999 Apr;57(4):557-81.  [PMID:10235693]
3. Roehrborn CG, Boyle P, Nickel JC, Hoefner K, Andriole G, ARIA3001 ARIA3002 and ARIA3003 Study Investigators. Efficacy and safety of a dual inhibitor of 5-alpha-reductase types 1 and 2 (dutasteride) in men with benign prostatic hyperplasia. Urology 2002 Sep;60(3):434-41.  [PMID:12350480]
4. Debruyne F, Barkin J, van Erps P, Reis M, Tammela TL, Roehrborn C, ARIA3001, ARIA3002 and ARIB3003 Study Investigators. Efficacy and safety of long-term treatment with the dual 5 alpha-reductase inhibitor dutasteride in men with symptomatic benign prostatic hyperplasia. Eur Urol 2004 Oct;46(4):488-94; discussion 495.  [PMID:15363566]
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