Antiandrogens Flashcards
How do antiandrogens work?
block androgen receptors or suppress androgen production
What are the three classes of antiandrogens?
- 5a-reductase inhibitors
- gonadotropin-releasing inhibitors
- hormonal oncological agents with androgen deprivation effects
What is an example of a 5a-reductase inhibitor?
Finasteride
What are 5a-reductase inhibitors indicated for?
treatment of benign prostatic hyperplasia + male pattern baldness
What is the mechanism of action of finasteride (propecia/proscar)?
inhibits the action of 5-alpha reductase (normally converts testosterone to dihydrotestosterone to cause male sex changes)
How long should finasteride (propecia/proscar) be administered before beneficial affect is determined?
6-12 months
True or false
Finasteride (propecia/proscar) is nonselective in its inhibition of 5-alpha reductase
False - it is highly selective (up to 100x more) to receptors in the prostate and hair follicles
How is finestaride metabolized?
Extensively by the liver; monitor patients with hepatic impairment
Adverse effects of the 5α-reductase inhibitors:
- erectile/ejaculatory dysfunction
- decreased libido
- gynecomastia
- small risk for high grade prostate cancers
Any increase in PSA levels while taking finasteride (propecia/proscar) may be a sign of what adverse effect?
high grade prostate cancer
What is an example of a gonadotropin-releasing inhibitors? (GnRH)
Leuprolide
What is Leuprolide indicated for?
- advanced prostate cancer
- advanced breast cancer
- management of endometriosis
- uterine fibroids (polycystic ovarian syndrome)
- treatment of precocious puberty
What is an example of a hormonal oncological agents with androgen deprivation effects?
Flutamide
MOA of Flutamide:
inhibits androgen uptake and acts like a competitive androgen receptor antagonist in target tissues (sex organs)
Flutamide indication:
treat moderate to advanced or metastatic prostate cancer (usually in combination) & female androgen excess syndrome
