Prostate Anti-Androgen Drugs

== Anti-androgen Trials ==

Drug Mechanism Prostate Cancer
Leuprolide acetate (Lupron) GnRH agonist/antagonist Treat in adjuvant and metastatic settings
Bicalutamide (Casodex)
cyproterone acetate
androgen receptor blocker
(ie. antiandrogen)
block cllinical flair
Finesteride (Proscar) 5-$\alpha$-reductase inhibitor prevents cancer in 25%
Terazosin (HYTRIN®) alpha-1-blocker For BPH not Testosterone reduction or prostate cancer, relaxes smooth muscle

GnRH agonist/ antagonist

  • Formulation available: leuprolide (Lupron) and goserelin (Zoladex)

Mechanism: analogues of LHRH

  1. initial surge in LH with a rise in testosterone (may result in clinical flare)
  2. followed by down-regulation of LH receptors in the pituitary and
  3. inhibition of LH release
  4. testosteron fall in 2 to 3 weeks

Complications

  • LHRH alone is contraindicated in: painful metastasis, ureteral obstruction and impending spinal cord compromise
  • Osteoporesis
  • Gynecomastia, more common with Casodex
  • Impotence
  • Hot Flahses
  • Body Hair Loss

Androgen Receptor Blockers

type I: steroidal

* Formulation available:
* suppress LH levels and lower serum testosterone

type II: non-steroidal

  • Formulation available: flutamide (Eulexin), bicalutamide (Casodex), and nilutamide (Nilandron)

Mechanism

  • binds AR in prostate and pituitary and hypothalamus
  • thus no negative feed back on LH synthesis (ie. unlike LHRH agonist, LH does not decrease)
  • testosterone levels increase

Complications

  • Potency sparing
  • more Gynecomastia
  • less decrease in libido
  • less muscle wasting
  • less urinary urgency

5-$\alpha$-Reductase Inhibitor

Type II
Finesteride (Proscar) [1] [3] [2]

  • reduces PSA by 50% in men with BPH but without cancer
  • reduces overall prostate cancer risk by 24.8% or more at 7-years.
  • increase sensitivity of PSA test for detecting prostate cancer especially high-grade prostate cancer but does not increase the incidence of high-grade prostate cancer (conflicting studies)
  • reduces the symptoms of benign prostatic hyperplasia
  • impotency is a side-effect

Alpha-1-receptor blocker

Terazosin (HYTRIN®) [2]

  • does not effect PSA
  • treatment for BPH not prostate cancer

== Anti-androgen Trials ==

Bibliography
1. Etzioni RD, Howlader N, Shaw PA, Ankerst DP, Penson DF, Goodman PJ, Thompson IM. Long-term effects of finasteride on prostate specific antigen levels: results from the prostate cancer prevention trial.
J Urol. 2005 Sep;174(3):877-81. Erratum in: J Urol. 2005 Nov;174(5):2071.
2. Keetch DW, Andriole GL, Ratliff TL, Catalona WJ. Comparison of percent free prostate-specific antigen levels in men with benign prostatic hyperplasia treated with finasteride, terazosin, or watchful waiting.
Urology. 1997 Dec;50(6):901-5. PMID: 9426721
3. Thompson IM, Chi C, Ankerst DP, Goodman PJ, Tangen CM, Lippman SM, Lucia MS, Parnes HL, Coltman CA Jr. Effect of finasteride on the sensitivity of PSA for detecting prostate cancer. J Natl Cancer Inst. 2006 Aug 16;98(16):1128-33. PMID: 16912265
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