Antiandrogens Flashcards
Which antiandrogen is an 5-alpha reductase inhibitor?
Finasteride (propecia/proscar)
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)
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 long should finasteride (propecia/proscar) be administered before beneficial affect is determined?
6-12 months
What are the indications for finasteride (propecia/proscar)?
Benign prostatic hyperplasia (BPH)
Male patterned baldness
Finasteride should be used cautiously in patients with _________ insufficiency
Hepatic
(No dosage adjustments required for renal insufficiency)
Any increase in PSA levels while taking finasteride (propecia/proscar) may be a sign of what adverse effect?
high grade prostate cancer
PSA levels should be checked ___________ after initiating finasteride (propecia/proscar)
6 months
What are the adverse effects associated with 5-alpha reductase inhibitors?
- small risk for high grade prostate cancers
- decreased libido
- impotence/ED
- gynecomastia
What medication class does flutamide (eulexin) belong to?
Direct antiandrogens
What is the mechanism of action of flutamide (eulexin)?
it is a competitive androgen receptor antagonist in target tissues (sex organs)
What are the indications for flutamide (eulexin) use?
- Prostate cancer (moderate-advanced or metastatic)
- female androgen excess syndrome
What is flutamide’s (eulexin) black box warning?
- Hepatic failure
- Hepatic encephalopathy
- Death related to the above
Leuprolide acetate (Lupron) is a _______ analog
GnRH (gonadotropin releasing hormone)
What is the MOA of Leuprolide (Lupron)?
Agonist of the GnRH receptors in the pituitary - subsequently suppresses further release of LH and FSH
* causes reversible chemical castration
