Information about Exemestane
Exemestane is a steroidal inhibitor of aromatase which effectively blocks estrogen synthesis in postmenopausal women and is used as therapy of estrogen receptor positive breast cancer, usually after resection and after failure of tamoxifen.
Liver safety of Exemestane
Exemestane has been associated with a low rate of serum enzyme elevations during therapy and rare instances of clinically apparent liver injury.
Mechanism of action of Exemestane
Exemestane (ex" e mes' tane) is an aromatase inhibitor that acts as an antiestrogen and is used to treat postmenopausal women with estrogen receptor positive breast cancer. Aromatase is the enzyme responsible for the conversion of testosterone to estrone (E1) and of androstenedione to estradiol (E2). Highest levels of aromatase are found in the ovary and placenta, which are the major sources of estrogen in premenopausal women. However, aromatase is also found in other tissues, such as liver, kidney, adrenals, brain, muscle and subcutaneous fat where it is also active in producing estrogens, although at low levels. These tissues are the major source of estrogen in postmenopausal women. Inhibitors of aromatase were developed to block the synthesis of estrogen in the peripheral tissues and, thus, as antiestrogen therapy of estrogen receptor positive breast cancer in postmenopausal women. Exemestane is a steroidal, specific aromatase inhibitor which has little or no effect on adrenal glucocorticoid or mineralocorticoid synthesis.
FDA approval information for Exemestane
Exemestane was approved for use in postmenopausal women with estrogen receptor positive breast cancer in the United States in 1999. Exemestane is available in 25 mg tablets in generic forms and under the brand name Aromasin. Current indications are as adjuvant therapy in postmenopausal women with estrogen sensitive breast cancer after failure, intolerance or as replacement of tamoxifen. Exemestane is given in doses of 25 mg once daily by mouth for up to five years.
Side effects of Exemestane
Common side effects include hot flashes, night sweats, arthralgias, fatigue, dizziness, nervousness, insomnia, nausea, weight gain and headache. Uncommon, but potentially severe adverse reactions include reduction in body mineral density and embryo-fetal toxicity.