@Article{,
AUTHOR = {Kevin R. Loughlin},
TITLE = {The clinical applications of five-alpha reductase inhibitors},
JOURNAL = {Canadian Journal of Urology},
VOLUME = {28},
YEAR = {2021},
NUMBER = {2},
PAGES = {10584--10588},
URL = {http://www.techscience.com/CJU/v28n2/60328},
ISSN = {1488-5581},
ABSTRACT = {<b>Introduction:</b> Five-alpha reductase (5-AR) deficiency was first identified by Imperato-McGinley and Walsh as the cause of pseudohermaphroditism in two separate studies. The discoveries led to the development of finasteride (inhibitor of type 2 isoenzyme of 5-AR) and dutasteride (inhibitor of type 1 and type 2 isoenzymes of 5-AR).<br/>
Both drugs have been proven effective for the treatment of benign prostatic hyperplasia, improving voiding symptoms, reducing the risk of urinary retention, and decreasing the need for prostate surgery.<br/>
Five-alpha reductase inhibitors (5-ARIs) have also been demonstrated to be chemopreventive agents, reducing the risk of prostate cancer, although the risk of selecting out or mediating higher-grade prostate cancer remains uncertain. A lower dose of finasteride has been shown to be effective in the treatment of male pattern baldness.<br/>
<b>Materials and methods:</b> A Medline search was performed using mesh terms, benign prostatic hypertrophy, prostate cancer, male pattern baldness, female, and 5-AR.<br/>
<b>Results:</b> The Prostate Long Term Efficacy and Safety Study (PLESS) was a randomized double-blind study that established that finasteride resulted in a 22% increase in maximum flow rate and a 19% decrease in prostate volume. Further studies demonstrated that finasteride caused a significant reduction in the risk of the need for surgery and urinary retention over a 4-year period. Additional studies showed similar beneficial results with dutasteride.<br/>
The potential benefits of 5-ARIs as chemopreventive agents were examined in the Prostate Cancer Prevention Trial (PCPT) and the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) studies. In the 7-year PCPT trial, 18.4% of the finasteride group developed prostate cancer compared to 24.4% in the placebo group. In the 4-year REDUCE trial, there was a 22.8% reduction in prostate cancer at the conclusion of the study.<br/>
Despite the reduction in prostate cancer incidence in both the PCPT and REDUCE trials, each study showed an increased risk of high-grade prostate cancer in the treatment arms. The explanation for these observations remains an area of investigation.<br/>
Low-dose finasteride has also been used successfully for the treatment of male pattern baldness.<br/>
<b>Conclusions:</b> The use of 5-ARIs has been a major advance in urologic clinical practice. Urologists should be familiar with the underlying pharmacology of 5-ARIs as well as the clinical indications for their use.},
DOI = {}
}