Exemestane course with this drug for women
The anti-cancer drug, an aromatase inhibitor, has a structure similar to that of the natural steroid hormone androstenedione.
In postmenopausal women, estrogen is mainly produced by the conversion of androgens to estrogen by peripheral tissue aromatase enzymes. The mechanism of action of exemestan is an irreversible binding to the active aromatase fragment, resulting in inactivation of the enzyme.
Exemestane has no progestogenic or estrogenic activity. At high doses, only weak androgenic activity is observed. Does not affect the biosynthesis of cortisol and aldosterone in the adrenal gland.
Slight increases in LH and FSH levels in the blood are observed with low doses of eczema. However, this effect is not specific to drugs of this pharmacological class. It probably develops at the level of the pituitary gland according to the principle of reaction: a decrease in estrogen levels stimulates the secretion of gonadotropins in the pituitary gland in postmenopausal women.
After oral administration, it is rapidly absorbed from the gastrointestinal tract. Cmax is 18 ng / ml after a single dose of 25 mg after a meal and is reached within 2 hours.
Upon reaching Cmax, the plasma concentration of the active substance decreases; The final T1 / 2 is approximately 24 hours. Exemestane is widely distributed in tissues. Plasma protein binding is approximately 90% and is independent of total concentration.
After repeated daily administration of 25 mg, plasma concentrations remained unchanged after a single dose.
Exemestane is generally highly purified due to metabolism. It is metabolized by the CYP3A4 isoenzyme by oxidation of the methylene group to position 6 and / or reduction of the 17-keto group by aldocetoreductase. As a result, a large number of secondary metabolites are formed, but the amount is very small compared to the dose used. In connection with aromatase inhibition, these metabolites are less active than inactive or unmodified substances.
Excreted in urine and feces. The excretion of exmethane and its metabolites usually stops within a week. Less than 1% is excreted unchanged in the urine.
Use during pregnancy and lactation
Contraindicated during pregnancy.