Tamoxifen is an antimetabolite (antiestrogen) that competitively binds to estrogen receptors in the cytoplasm of estrogen-dependent tumor cells. Together with them, it penetrates into the nucleus, where it blocks the interaction of estrogens with its receptors.
After oral administration, the drug is rapidly absorbed and maximum serum concentrations are reached within 4-7 hours.
Stable concentrations (approximately 300 ng / ml) are achieved after a four-week treatment with a daily intake of 40 mg. Tamoxifen binds well to serum albumin (> 99%). As a result of metabolism, in the process of hydroxylation, demethylation and conjugation, a number of metabolites are formed, having pharmacological profile similar to the initial chemical compound, thus contributing to the achievement of a therapeutic effect. The half-life is 7 days. Isolation occurs mainly through stool masses.
Metastatic breast cancer, especially in patients who are in menopause, endometrial cancer, kidneys, soft tissue sarcoma, anovulatory infertility, postpartum agalactia, oligospermia, pituitary tumors. It is noted that the prophylactic administration of tamoxifen to women at risk of breast cancer reduces their incidence by 45% compared to women of the same risk but not taking the drug.
With breast cancer, endometrial or kidney 10-20 mg 2-3 times a day. The course dose is 2.4-9.6 g; Treatment continues until the regression of the process and within the next 1-2 months.
With anovulatory infertility 10 mg twice a day for 4 days, starting from the 2nd day of menstruation, then 20 mg twice a day, and if necessary, 40 mg 2 times a day.
With postpartum agalactia 10 mg 4 times a day for 5 days.
With oligospermia 10 mg twice a day.
Lack of appetite, nausea, vomiting. Feeling of fatigue, drowsiness, dizziness, erythema, hypercalcemia, moderate metrorrhagia. Pulmonary embolism, thrombosis. Hyperplasia of the endometrium, polyposis or endometrial carcinoma, uterine fibroid, cystic swelling of the ovaries in women, retinopathy, corneal opacity, heat attacks, weight gain, genital itching, changes in the menstrual cycle. Headache. Rarely, fever, leukopenia, sometimes with anemia and / or thrombocytopenia, nentropenia. Change in liver enzyme levels, and in rare cases, with more serious disorders, including fatty liver infiltration, cholestasis and hepatitis.
Absolute – pregnancy, thrombophlebitis, hypersensitivity to tamoxifen.
Relative – leukopenia, thrombocytopenia, hyperlipidemia, hypercalcemia, cataract.
increased anti-estrogenic side effects. Specific antidote is not available, and treatment should be symptomatic.
In the process of treatment, it is necessary to control the number of leukocytes, platelets, calcium level, and the parameters of the blood coagulation system.
It is not effective in the treatment of patients with metastases (especially in the liver).
In a number of women taking tamoxifen for the treatment of breast cancer in the pre-pellicle, there is a lack of menstruation.
it is recommended to carry out careful monitoring of patients with simultaneous application of anticoagulants of the coumarin type.
Lactation: There is no data on the isolation of tamoxifen in breast milk in women, so its use during lactation is not recommended.