Anastrozole (Arimidex) is a drug indicated in the treatment of breast cancer in post-menopausal women. It is used both in adjuvant therapy (i.e. following surgery) and in metastatic breast cancer. It has the effect of decreasing the amount of estrogen that the body makes.
Anastrozole belongs in the class of drugs known as aromatase inhibitors. It inhibits the enzyme aromatase, which is responsible for converting androgens (produced by women in the adrenal glands) to estrogen.
The drug is appropriately used when using substantial amounts of aromatizing steroids, or when one is prone to gynecomastia and using moderate amounts of such steroids. Arimidex does not have the side effects of aminoglutethimide (Cytadren) and can achieve a high degree of estrogen blockade, much more so than Cytadren. It is possible to reduce estrogen too much with Arimidex, and for this reason blood tests, or less preferably salivary tests, should be taken after the first week of use to determine if the dosing is correct.
As an aromatase inhibitor, Arimidex's mechanism of action -- blocking conversion of aromatizable steroids to estrogen -- is in contrast to the mechanism of action of anti-estrogens such as clomiphene (Klomen) or tamoxifen (Nolvadex, Tadex), which block estrogen receptors in some tissues, and activate estrogen receptors in others. During a cycle, if using Arimidex, there is generally no need to use Klomen as well, but there may still be benefits to doing so.
In one study, both .5mg and 1mg doses of Arimidex were shown to decrease estrogen by roughly 50%. The 1mg/day dose also increased testosterone levels by 58%. In that same study, in both groups, LH and FSH also went up slightly. This would seem to suggest that for use during a cycle, a dose of .5mgs/day would be sufficient to combat estrogen-related side effects. It is, however, important to remember that some estrogen is necessary to obtain optimal muscle growth. The lower estrogen levels provided by Arimidex seems, anecdotally at least, to produce a more "hard" and "quality" look for bodybuilders who have experimented with it´s use in either a cutting or bulking cycle.
I´d like to point out that the elevation in Testosterone provided by Arimidex is so large that it can be used as a "form" of testosterone replacement therapy for hypogonadal men. Clearly, this suggests its use in a post-cycle-therapy (as well as its previously discussed use within a cycle) to regain natural testosterone levels and full functioning of the HPTA (Hypothalamic-Testicular-Pituitary-Axis).
Literature provided by the original maker of Anastrozole (Arimidex, produced by Zeneca Pharmaceuticals) states that stable blood plasma concentrations of the compound are achieved after a mere 7 consecutive 1mg daily doses. Also, Arimidex is just over 80% effective at inhibiting aromatase. Thus, if you want to take it for the entire duration of a cycle of anabolic steroids, you can simply start taking it on the same day you begin your cycle. But can you use it for the entire duration of a cycle? Is it dangerous? Well, certainly reducing estrogen levels in your body is good from a body building point of view, as it reduces water-retention and the potential for gynocomastia (if there´s no estrogen in your body, you can´t get gyno, regardless of how much progesterone is floating around). Luckily this stuff is very mild on blood lipids (cholesterol) and doesn´t affect them adversely.
Store in temperature not exceeding 77oF(25oC), away from excess moisture.