Tamoxifen 20 mg – [30 tablets]

Tamoxifen is a non-steroidal drug from the group of triphenylethylenes, which has a combined spectrum of pharmacological action as both an estrogen antagonist and an estrogen agonist in various tissues. In patients with breast cancer in tumor cells, tamoxifen primarily exhibits an anti-estrogenic effect by preventing estrogen binding to estrogen receptors. Tamoxifen, as well as some of its metabolites, compete with estradiol for binding sites with cytoplasmic estrogen receptors in breast, uterine, vaginal, anterior pituitary lobe tissues and tumors with high estrogen receptor content. In contrast to the estrogen receptor complex, the tamoxifen receptor complex does not stimulate DNA synthesis in the nucleus, but inhibits cell division, which leads to regression of tumor cells and their death.

In women with estrogen-positive/nonspecific breast tumors adjuvant therapy with tamoxifen significantly reduces recurrence of the disease and extends life expectancy up to 10 years. A more pronounced effect is achieved with treatment for 5 years than with one- or two-year treatment, and does not depend on age, menopause, or the dose of tamoxifen or adjuvant chemotherapy.

In approximately 10-20% of postmenopausal women, the use of tamoxifen results in a decrease in plasma total cholesterol and low-density lipoprotein concentrations. In addition, there are reports that tamoxifen preserves bone mineral density in postmenopausal women.

Variability in clinical response to tamoxifen may be related to CYP2D6 isoenzyme polymorphisms. A low metabolic rate may be associated with a reduced therapeutic response to treatment. Recommendations for tamoxifen treatment of “slow” metabolizers of the CYP2D6 isoenzyme have not been developed.

Adjuvant therapy of early estrogen receptor-positive breast cancer; treatment of locally advanced or metastatic estrogen receptor-positive breast cancer; breast cancer (including in men after castration).

The drug also can be applied at other solid tumors, resistant to standard methods of treatment, in the presence of hyperexpression of estrogen receptors.

Hypersensitivity to tamoxifen and/or any other drug component; pregnancy and breast-feeding; children under 18 years of age (data on efficacy and safety in children are not available); concomitant use with anastrozole.

Caution:

Renal failure, diabetes mellitus, eye disease (including cataracts), deep vein thrombosis and thromboembolic disease (including history), hyperlipidemia, leukopenia, thrombocytopenia, hypercalcemia, concomitant therapy with indirect anticoagulants, concomitant therapy with CYP2D6 isoenzyme inhibitors, rare hereditary forms of lactose intolerance, lactase deficiency or glucose/galactose malabsorption (as the tablet contains the following components). because the composition of the tablet contains lactose).

Use during pregnancy and breastfeeding:

Tamoxifen is contraindicated during pregnancy and while breastfeeding.

Pregnancy

Pregnancy should be excluded prior to initiating therapy with tamoxifen. There are reports of spontaneous abortions, birth defects, and fetal death in women taking tamoxifen during pregnancy, although a cause-effect relationship has not been established. Premenopausal patients should be carefully screened for pregnancy before starting tamoxifen treatment.

Patients taking tamoxifen should use barrier or other non-hormonal methods of contraception both during treatment and for two months after discontinuation to prevent pregnancy.

Breastfeeding period

Breastfeeding is not possible during tamoxifen therapy because it inhibits lactation when used 20 mg twice a week. When tamoxifen is discontinued, milk production does not begin for several months, due to the continued therapeutic effect of tamoxifen. It is not known whether tamoxifen is excreted into breast milk, so if it is necessary to use the drug during lactation, breastfeeding should be stopped.