Drug Groups

approved; investigational

Description

Dutasteride belongs to a class of drugs called 5-alpha-reductase inhibitors, which block the action of the 5-alpha-reductase enzymes that convert testosterone into dihydrotestosterone (DHT). Finasteride also belongs to this group, but while dutasteride inhibits both isoforms of 5-alpha reductase, finasteride inhibits only one. Even so, a clinical study done by GlaxoSmithKline, the EPICS trial, did not find dutasteride to be more effective than finasteride in treating BPH. [Wikipedia]

Indication

For the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate gland to improve symptoms, and reduce the risk of acute urinary retention and the need for surgery.

Pharmacology

Dutasteride is a synthetic 4-azasteroid compound that is a selective inhibitor of both the type 1 and type 2 isoforms of steroid 5 alpha-reductase (5AR), intracellular enzymes that convert testosterone to 5 alpha-dihydrotestosterone (DHT). Type I 5a-reductase is predominant in the sebaceous glands of most regions of skin, including scalp, and liver. Type I 5a-reductase is responsible for approximately one-third of circulating DHT. The Type II 5a-reductase isozyme is primarily found in prostate, seminal vesicles, epididymides, and hair follicles as well as liver, and is responsible for two-thirds of circulating DHT.

Affected Organisms

Biotransformation

Hepatic. Extensively metabolized by CYP3A4 and CYP3A5 to active metabolites.

Absorption

60%

Half Life

5 weeks

Protein Binding

Highly bound to albumin (99%) and α-1 acid glycoprotein (96.6%).

Elimination

Dutasteride is extensively metabolized in humans. Dutasteride and its metabolites were excreted mainly in feces.

Distribution

* 300 to 500 L

References

External Links