Description
Exemestane: An Aromatase Inhibitor for Breast Cancer Treatment
Exemestane is a chemotherapy medication utilized in treating breast cancer. As an aromatase inhibitor, it acts as an antiestrogen. Estrogen fuels some breast cancers, particularly those with estrogen receptors (ERs), known as ER-positive, estrogen-responsive, or hormone-receptor-positive tumors. By inhibiting aromatase, which produces estrogen, exemestane reduces estrogen levels and suppresses cancer growth.
Medical Applications
Postmenopausal women with ER-positive early breast cancer use exemestane to complete five years of adjuvant hormone therapy. The US FDA approved this drug in October 1999. Exemestane is also prescribed to postmenopausal women with advanced breast cancer who haven’t responded to tamoxifen therapy.
Recent studies have shown that premenopausal women with hormone receptor-positive breast cancer may benefit from adjuvant therapy that includes ovarian suppression plus exemestane, as opposed to ovarian suppression plus tamoxifen. This treatment reduces the risk of recurrence and leads to longer survival times. Previously used mainly for postmenopausal women, exemestane may now be an option for premenopausal women receiving ovarian suppression.
Exemestane is an orally administered steroidal aromatase inhibitor utilized by postmenopausal women with ER-positive breast cancer. In postmenopausal women, estrogen is mainly produced by the aromatase enzyme in peripheral tissues (like adipose tissue in the breast) and some brain regions. This enzyme generates estrogen locally, and any excess estrogen that enters the bloodstream results from it escaping local metabolism.
As a type I inorganic steroidal aromatase inactivator, exemestane is structurally similar to 4-androstenedione. It functions as a false substrate for the aromatase enzyme, which becomes inactive after converting exemestane into an intermediate that permanently binds to the enzyme’s active site. This process prevents the enzyme from converting androgen into estrogen. In contrast, non-steroidal aromatase inhibitors like anastrozole and letrozole interfere with the aromatase’s heme.
Exemestane suppresses estrogen levels by 35% for estradiol (E2) and up to 70% for estrone (E1). However, this drug has a significant first-pass effect in the liver. In breast cancer patients, peak plasma concentrations are reached after 1.2 hours, while healthy individuals reach this point after 2.9 hours. Maximum aromatase inhibition occurs within two to three days, and 90% of the absorbed material is bound to plasma proteins. Within a week, 40% of the metabolites are eliminated through urine and 40% via feces. The terminal half-life is 24 hours.
Development and Distribution
Exemestane, also known as Aromasin, is a breast cancer treatment medication that functions as an aromatase inhibitor, similar to arimidex. Initially manufactured by Pharmacia & Upjohn, Pfizer now distributes the drug. The FDA approved this medication for postmenopausal women in 1999.
How It Works
Aromasin, a suicide aromatase inhibitor (AI), irreversibly inhibits the aromatase enzyme once bound. This mechanism differs from letrozole or arimidex, which prevent enzymes from recovering but can cause an “estrogen rebound” when discontinued. Some anabolic steroid users experience post-cycle gynecomecomastia due to this phenomenon. In breast cancer patients, Aromasin has been shown to decrease estrogen levels by up to 85%.
Use in Bodybuilding
Anabolic androgenic steroids (AAS) such as testosterone esters, nandrolones, dianabol, and boldenone convert to estrogen in the body. Uncontrolled estrogenic side effects may include gynecomastia (bitch tits), water retention, high blood pressure, and cardiovascular issues. If estrogen levels become unmanageable, a domino effect can occur, leading to fatigue, high blood pressure, lack of motivation, and other issues that counteract the goals of steroid use. Additionally, high estrogen levels after a cycle can hinder the body’s natural testosterone recovery.
On the other hand, a potent AI that eliminates too much estrogen may negatively impact libido, mood, and joint health. Since Aromasin is a suicidal aromatase inhibitor, it is crucial to manage the dosage and cycle it appropriately with your steroid cycle.
Benefits of Aromasin in Bodybuilding
Aromasin has several benefits for bodybuilders and athletes who use anabolic steroids. First, it can effectively manage and control estrogen levels, reducing the risk of estrogenic side effects such as gynecomastia, water retention, and high blood pressure. Controlled estrogen levels can result in a leaner, more defined physique, as well as improved cardiovascular health and reduced risk of estrogen-related complications.
Second, Aromasin may contribute to better muscle gains, as studies have shown a correlation between lower estrogen levels and increased muscle protein synthesis. This can lead to improved muscle growth and recovery, which are essential for bodybuilders and athletes looking to maximize their performance and physique.
Lastly, Aromasin has been reported to have a positive impact on cholesterol levels. Unlike other aromatase inhibitors, Aromasin does not appear to negatively affect the lipid profile, making it a safer choice for long-term use in managing estrogen levels.
Dosage Recommendations
The appropriate dosage depends on the individual and the amount of aromatizing compounds they are taking. A good starting dosage is 12.5mg every day (ED) or 25mg every other day (EOD). Users should monitor their body’s response to the initial dosage through blood tests and adjust as needed. Anabolic steroid users typically find a dosage they prefer and stick to it. If joint issues arise, reduce the dosage; if estrogen-related issues such as swollen or sensitive breasts or water retention occur, increase the dosage.
