I was just reading this so thought I'd post it:
Spironolactone has several properties that make it suitable for use in treating hirsutism. It interferes with the production of testosterone and it increases the metabolism of any testosterone that is produced. Spironolactone binds to cell androgen receptors and blocks them from binding to naturally produced androgens. In addition with long term spironolactone use, there is a gradual reduction in 5 alpha reductase activity. It is this enzyme that converts testosterone to the more potent, hair follicle stimulating, dihydrotestosterone.
Also:
Finasteride (marketed as Propecia and Proscar)
Promoted for use in treating pattern baldness and benign prostate hyperplasia, respectively, it's a type II 5alpha reductase inhibitor. This enzyme blocks the conversion of testosterone to dihydrotestosterone (DHT), a potent stimulator of hair loss in scalp follicles and hair growth in body hair follicles that have androgen receptors.
When finasteride was tested on postmenopausal women with pattern baldness there was little or no response. However, in trials for hirsutism finasteride has some significant promise. Results with finasteride alone in some trials have been comparable with oral antiandrogens, and the combination of finasteride plus other antiandrogens have shown an improved effect over using treatments separately. Although it may not be an appropriate treatment in every situation, finasteride is a readily available and relatively safe treatment option. The most significant side effect is that male fetuses will develop with female genitalia in any pregnant woman using finasteride. Consequently, dermatologists ensure one or more forms of birth control are used by any woman using finasteride. Other side effects reported include breast enlargement and increased libido (in contrast to decreased libido in men).
I've always thought it interesting that what causes hirsutism is the same thing that male pattern baldness.
It describes more treatments, including the CPA which isn't available in the U.S.
[url]http://www.hairfacts.com/methods/rxoral.html[/url]