5-alpha-reductase inhibitor
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2008-01-28T23:55:27Z
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'''5α-reductase inhibitors''' (or '''5-alpha-reductase inhibitors''') are a group of [[medication|drugs]] with [[antiandrogen]]ic activity, used in the treatment of [[benign prostatic hyperplasia]] and androgenic (or androgenetic) [[alopecia]]. These drugs decrease the levels of available [[5-alpha reductase|5α-reductase]] prior to testosterone binding with the enzyme, thus reducing levels of [[dihydrotestosterone]] that derives from such a bond.
==Clinical use==
===Indications===
5α-reductase inhibitors are clinically used in the treatment of conditions which are exacerbated by [[dihydrotestosterone]]. Specifically, these indications may include: (Rossi, 2004)
*mild-to-moderate [[benign prostatic hyperplasia]]
*androgenic (or androgenetic) [[alopecia]]
===Adverse drug reactions===
[[Adverse drug reaction]]s (ADRs) experienced with 5α-reductase inhibitors are generally dose-dependent. Common ADRs include [[impotence]], decreased [[libido]], decreased ejaculate volume. Rare ADRs include: breast tenderness and enlargement, and [[allergy|allergic]] reaction. (Rossi, 2004)
==Pharmacology==
The enzyme 5α-reductase is involved in the conversion of [[testosterone]] to the active form [[dihydrotestosterone]] by reducing the Δ4,5 double-bond. In [[benign prostatic hyperplasia]], dihydrotestosterone acts as a potent cellular [[androgen]] and promotes [[prostate]] growth - inhibiting the enzyme reduces the excessive prostate growth. In alopecia, pattern-baldness is one of the effects of androgenic receptor activation. Reducing the levels of dihydrotestosterone thus reduces alopecia.
==Examples==
*[[finasteride]] (Proscar, Propecia)
*[[dutasteride]] (Avodart)
*[[FCE 28260]], an experimental compound
==References==
* Rossi S (Ed.) (2004). ''[[Australian Medicines Handbook]] 2004''. Adelaide: Australian Medicines Handbook. ISBN 0-9578521-4-2
{{Urologicals}}
[[Category:5-alpha-reductase inhibitors|*]]
[[pt:Inibidor da 5-alfa-redutase]]