Manufacturer: Alpha PharmaPack: 2.5mg (50 pills)Chemical Substance: Letrozole
Pharmacological action – antitumor.
Competitively binds to the prosthetic part (heme) of cytochrome P450, the aromatase subunit involved in the transformation of androgens to estrone and estradiol, inhibits the biosynthesis of estrogens in tissues and, in particular, removes their stimulating effect on tumor growth.
After oral intake is fully absorbed, bioavailability is close to 100%. In the vascular bed more than half (60%) binds to proteins (mainly albumin), accumulates in red blood cells. At average therapeutic doses, the equilibrium concentration is reached after 2-6 weeks. The volume of distribution is 1.9 l / kg. In the liver it breaks down, forming inactive derivatives. T1 / 2 – about 48 hours. It is excreted as the products of biotransformation mainly by the kidneys. Do not cumulate.
Induced, with prolonged daily intake, a decrease in the level of estrogens in plasma (an average of 85% of the baseline level) in advanced breast cancer in women after 50 years of age with both sufficient and unknown estrogen receptor levels leads to complete or partial regression of the tumor In 23% of cases, a decrease in the number of relapses and deaths. Letrozole is considered an alternative to tamoxifen in postmenopausal women and is used when tamoxifen (or toremifene) is ineffective.
Use of the substance Letrozole
Common breast cancer, mainly in postmenopausal women, incl. With resistance to anti-estrogen therapy.
Hypersensitivity, pre-menopausal period, marked renal dysfunction (Cl creatinine <10 ml / min), pregnancy, lactation (terminate).