Aromasin - Exemestane
Pharmaceutical Name: Exemestane
Drug Class: Aromatase Inhibitor
Active Life: 24-30 hours
Exemestane is a steroidal suicide aromatase inhibitor/irreversible aromatase
inactivator, lowering production of estrogen in the body by blocking the
aromatase enzyme. Similar in structure to formestane, exemestane's medical use
like most aromatase inhibitors is for treatment of estrogen-dependent breast
cancer. It is usually only prescribed in those cases where therapies using
less aggressive compounds have not produced the results hoped for, such as
selective estrogen receptor modulators.
For use by strength athletes and bodybuilders, exemestane has several
properties that would be beneficial. First, exemestane reportedly can lower
estrogen 85% on average (1). In doing so of course this will aid in the
prevention of estrogen related side effects caused by aromatizing steroids.
The drug also raises testosterone levels in users which can be advantageous if
used during post-cycle therapy (2). Add to this the fact that there is some
evidence that exemestane may elevate levels of insulin growth factor [IGF]
Like other aromatase inhibitors, there is also conflicting information and
studies regarding the effect that exemestane has on users blood
lipids/cholesterol, with some studies indicating that the compound has little
to no effect while others say that it is quite harsh (4,5).
Use/Dosing of Aromasin - Exemestane
Exemestane reaches peak plasma concentrations within 2 hours following the
oral administration of a 25 mg dose (1). The active life of the drug is
between 24 and 30 hours. This is significant since it is quite shorter than
for the non-steroidal inhibitors (1). A single oral dose of 25 milligrams of
exemestane causes a relatively long-lasting reduction in plasma and urinary
estrogen levels, with maximal suppression occurring approximately 2 to 3 days
after dosing and persists for about 4 to 5 days (1, 4).
It has been shown that 25 milligrams of exemestane is basically just as
effective as 50 milligrams at suppressing estrogen, raising testosterone
levels, and levels of IGF (2). It is therefore unnecessary to go higher in
doses than 25 milligrams per day. Due to the active life of the compound
exemestane should be administered roughly once every twenty-four hours.
It appears that the only negative aspect of the compound in terms of the
dosing schedule is that it takes approximately seven days for it to reach
steady blood plasma levels. However, this is not a major hindrance to its use.
It just simply requires that a user begin using exemestane a week prior to
when they want the effect of the compound to be full realized.
Risks/Side Effects of using Aromasin - Exemestane
Exemestane has no significant drug toxicity at doses up to 600 milligrams per
day. It is well tolerated by most users with the maximum tolerated dose
toxicity not yet being identified (1). Negative side effects related to the
use of this compound are usually quite mild and can include things such as
transient gastrointestinal effects, hot flashes, nausea, and/or fatigue (1,
2). As previously mentioned, the effect of exemestane on the blood
lipids/cholesterol are unknown due to the conflicting research and therefore
should be monitored when using the compound. Sexual dysfunction is also a
possibility due to the lowering of estrogen levels as well. However reports of
this are relatively rare.
Due to the mild negative side effects associated with the compound, as well as
the potency of the drug in alleviating estrogen-related side effects when
administering aromatizing anabolic steroids, exemestane is seemingly a
relatively safe choice when looking for an aromatase inhibitor.
1. Brueggemeier RW. Overview of the pharmacology of the
aromatase inactivator exemestane. Breast Cancer Res Treat 2002;74:177-185.
2. Mauras N, Lima J, Patel D, Rini A, di Salle E, Kwok A, Lippe B.
Pharmacokinetics and dose finding of a potent aromatase inhibitor, aromasin (exemestane),
in young males. J Clin Endocrinol Metab. 2003 Dec;88(12):5951-6.
3. Martinetti A, Zilembo N, Ferrari L, Massimini G, Polli A, La Torre I,
Giovanazzi R, Pozzi P, Bidoli P, De Candis D, Seregni E, Bombardieri E,
Bajetta E. Bone turnover markers and insulin-like growth factor components in
metastatic breast cancer: results from a randomised trial of exemestane vs
megestrol acetate. Anticancer Res. 2003 Jul-Aug;23(4):3485-91.
4. Buzdar AU. An overview of the pharmacology and pharmacokinetics of the
newer generation aromatase inhibitors anastrozole, letrozole, and exemestane.
Cancer. 2002 Nov 1;95(9):2006-16.
5. Atalay G, Dirix L, Biganzoli L, Beex L, Nooij M, Cameron D, Lohrisch C,
Cufer T, Lobelle JP, Mattiaci MR, Piccart M, Paridaens R. The effect of
exemestane on serum lipid profile in postmenopausal women with metastatic
breast cancer: a companion study to EORTC Trial 10951, 'Randomized phase II
study in first line hormonal treatment for metastatic breast cancer with
exemestane or tamoxifen in postmenopausal patients'. Ann Oncol. 2004
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