Formestane was the first selective aromatase inhibitor to be developed as a prescription drug, first appearing in Europe during the mid-1990s under the Lentaron Depot brand name. It was sold by Novartis, which marketed Lentaron Depot in two-dozen countries including Argentina, Austria, Belgium, Brazil, Canada, Chile, Czech Republic, Denmark, France, Germany, Greece, Hong Kong, Ireland, Israel, Italy, Malaysia, Netherlands, Portugal, South Africa, Spain, Switzerland, Turkey, and the United Kingdom. With the emergence of newer and more effective aromatase inhibitors, however, formestane soon lost market presence at a rapid rate. Most of the initial Lentaron Depot preparations have since been discontinued. The drug remains available today, but only in a small number of nations. This includes Austria, Brazil, Czech Republic, Hong Kong, and Turkey.
How is Formestane Supplied
Formestane is most commonly supplied in a sterile solution containing 125 mg/mL of drug in a 2 mL ampule.
Structural Characteristics of Formestane
Formestane is classified a steroidal selective irreversible aromatase inhibitor. It has the chemical designation 4- Hydroxyandrost-4-ene-3,17-dione.
Formestane Side Effects
Common side effects associated with the use of an aromatase inhibitor include hot flashes, joint pain, weakness, fatigue, mood changes, depression, high blood pressure, swelling of the arms/legs, and headache. Aromatase inhibitors may also decrease bone mineral density, which may lead to osteoporosis and an increase in fractures in susceptible patients. Some individuals may also respond to the medication with gastrointestinal side effects including nausea and vomiting. Aromatase inhibitors can harm the development of an unborn fetus, and should never be taken or handled during pregnancy. When taken by men (as an off-label use) to reduce estrogenicity during prolonged periods of steroid treatment, aromatase inhibitors may increase cardiovascular disease (CVD) risk by retarding some beneficial properties of estrogen on cholesterol values. Studies have demonstrated that when an aromatizable steroid such as testosterone enanthate is taken in conjunction with an aromatase inhibitor, suppression of HDL (good) cholesterol levels becomes significantly more pronounced. Since the estrogen receptor agonist/antagonist Nolvadex generally does not display the same anti-estrogenic (negative) effect on cholesterol values, it is usually favored over aromatase inhibitors for estrogen maintenance by male bodybuilders and athletes concerned with cardiovascular health.
Formestane is indicated for the treatment of advanced breast cancer in postmenopausal women. The recommended dosage is 250 mg by intramuscular injection (buttock) every two weeks. Although not a medically approved form of the drug, studies have demonstrated that a similar level of estrogen suppression can also be achieved with oral use of formestane. Due to poor bioavailability, however, the dose needed is around 250 mg per day . When used (off-label) to mitigate the estrogenic side effects of anabolic/androgenic steroid use or increase muscle definition, male athletes and bodybuilders often take 250 mg every two weeks by injection, or 250 mg per day orally.
Formestane is not widely available as a prescription drug, and consequently is rarely circulated in the athletic community.
Newbies Research Guide reference
Formestane is the first in a new line of selective, steroidal-based aromatase inhibitors. It is currently available in a few European countries, and is expected to reach U.S. shelves before long. Formestane is structurally a derivative of androstenedione, most specifically 4-OH androstenedione. Androstenedione is a readi- ly aromatized steroid, so clearly this similarity welcomes interaction with the aromatase enzyme. Its activity in the body is in fact that of a suicide inhibitor, meaning that the compound will become inextricably bound to the aromatase enzyme upon contacting it. Its effect is therefore comparatively much more lasting than that seen with reversible, competitive inhibitors. This is no doubt the reason formestane was shown in studies to be as much as 60 times more potent than aminoglutethimide. As with Arimidex, this compound can help achieve near total suppression of aromatase.
Due to poor oral bioavailability, formestane is commercially prepared as an injectable product. The typical recommendation is an injection of 250mg (typically 1 ampule or injection) every two weeks. Though estrogen suppression can be marked with this dosing pattern, some studies do suggest that by the second week (near the time the dosage is to be repeated) estrogen levels may begin to recover. Although a more frequent schedule may provide more stable results, again cost is a prohibiting factor. I am looking at a current mail-order list in which a single 250mg ampule of formestane sells for $249. This would equate to a monthly expense of around $500, roughly twice the cost of the recommended anastrozole dose. It is of course also very doubtful that, with the high potency of this compound, an athlete would ever have trouble with the recommended schedule.
Wlliam Llewellyn (2011) - Anabolics
Newbies Research Guide