After oral administration, tamoxifen is well absorbed. The maximum serum concentration is achieved in the range of 4 to 7 hours after receiving a single dose. Equilibrium concentration in serum when using 20-40 mg / day is typically achieved after 3-4 weeks of administration. Communication to plasma proteins is 98%. It is metabolized in the liver with the formation of several metabolites.
The main serum metabolite, subsequent metabolites possess antiestrogenic essentially the same properties as the starting material. Tamoxifen and its metabolites accumulate in the liver, lung, brain, pancreas, skin and bones. Tamoxifen is metabolized primarily by means of fluoxymesterone halotestin, which further metabolized isoenzyme using to another active metabolite – endoksifena. Patients with a deficiency of the enzyme endoksifena concentration about 75% lower than in patients with normal activity . Application of strong isoenzyme inhibitors as much endoksifena reduces the concentration in the blood.
Tamoxifen excretion from the body has a biphasic pattern with an initial half-life of 7 to 14 hours followed by slow and the terminal half-life of 7 days. It provided mainly as conjugates, mainly through the intestine and only small amounts of its allocated kidneys.
Adjuvant therapy of early breast cancer with estrogen-receptor-positive; treatment of locally advanced or metastatic breast cancer with estrogen-receptor-positive; breast cancer (including men after castration).
The preparation can also be applied in other solid tumors, refractory to standard treatments, in the presence of overexpression of estrogen receptors.
- Increased sensitivity to tamoxifen and / or any other component of the formulation.
- Pregnancy and breast-feeding.
- Children’s age (18 years).
Renal failure, diabetes, eye diseases (including cataracts), deep vein thrombosis and thromboembolic disease (including history), hyperlipidemia, leukopenia, thrombocytopenia, hypercalcemia, concomitant therapy with indirect anticoagulants, rare hereditary forms fluoxymesterone halotestin of intolerance lactose, lactase deficiency or malabsorption of glucose / galactose (as in the tablet contains lactose).
Application of pregnancy and during breastfeeding
Do not use this drug hexane during pregnancy. There are reports of spontaneous abortions, congenital malformations and fetal deaths in women taking tamoxifen during pregnancy, despite the fact that a causal link has not been established.
Breastfeeding is not possible during tamoxifen therapy because it inhibits lactation. Upon termination of the use of tamoxifen milk production does not begin within a few months due to the preservation of the therapeutic effect of the drug. It is not known whether tamoxifen passes into breast milk gets, so if you need treatment with Tamoxifen hexane lactation should decide the issue of termination of breastfeeding.
Dosing and Administration
The tablets should be taken with liquid, squeezed small amounts of liquid in one go in the morning or by separating the required dose into two doses, morning and evening.
The dosage regimen is generally determined individually depending on the evidence. The maximum daily dose is 40 mg.
As a standard recommended dose of 20 mg tamoxifen.
If signs of progression of the disease reception cancel preparation.
The duration of treatment depends fluoxymesterone halotestin on the severity of the disease usually requires long-term treatment. As an adjuvant therapy in women with breast cancer the recommended duration of treatment with tamoxifen for about 5 years.