Tamoxifen: what it is for, how to take it and side effects

Tamoxifen is a medicine indicated for the treatment of breast cancer that depends on estrogen for its growth, as it works by blocking the action of this hormone, preventing it from binding to breast cancer cells, and in this way, preventing the growth of the tumor.

This medicine can be found in pharmacies or drugstores, or provided by the SUS or health plans, in the form of 10 or 20 mg tablets, with the trade name Nolvadex, with the similar names Tacfen, Festone or Taxofen, for example, or in generic form as tamoxifen citrate.

Tamoxifen should be used as recommended by the oncologist, at the dose and for the duration of treatment established by the doctor.

What is it for

Tamoxifen is indicated for the treatment of early-stage breast cancer with positive or unknown estrogen receptor.

This medicine works by inhibiting the binding of estrogen to cancer cells, preventing tumor growth. It can be used regardless of age, whether the woman is in menopause or not, and the dose to be taken.

This medicine can also be used by men with breast cancer who are estrogen receptor positive.

How to drink

Tamoxifen tablets should be taken orally, with a little water, and ingested whole without breaking or chewing, always at the same time each day.

Generally, the recommended dose of tamoxifen is 1 tablet of 20 mg, in a single dose, or 2 tablets of 10 mg. However, if there is no improvement after 1 or 2 months, the doctor may increase the dose to 20 mg, twice a day.

The duration of treatment with tamoxifen can vary from 5 to 10 years and should always be used according to the oncologist’s instructions.

What to do if you forget to take a dose?

If you forget to take a dose of tamoxifen, you should take it as soon as you remember, no later than 12 hours late. The next dose should be taken at the usual time.

If the dose has been missed for more than 12 hours, you should contact your doctor, as it is not recommended to take two doses less than 12 hours apart.

Possible side effects

The most common side effects that may occur during treatment with tamoxifen are nausea, fluid retention, swollen ankles, vaginal bleeding or discharge, hot flashes, mood changes, depression, blistering, itching or peeling skin, or tiredness. .

Additionally, tamoxifen may increase the risk of blood clots, pulmonary embolism, thrombosis or stroke.

Therefore, you should seek medical help immediately if you experience symptoms such as sudden numbness or weakness, severe headache, slurred speech, vision or balance problems, chest pain, sudden cough, shortness of breath, dizziness, or pain, swelling or heat in one leg.

Who shouldn’t use

Tamoxifen should not be used by children, adolescents, pregnant or breastfeeding women, or by people who are allergic to tamoxifen citrate or any other substance present in the tablets.

Furthermore, tamoxifen should also not be used by people who use anticoagulant medications, such as warfarin, chemotherapy drugs, rifampicin and selective serotonin reuptake inhibitor antidepressants, such as paroxetine or fluoxetine, for example.

This remedy should also not be used at the same time with aromatase inhibitors, such as anastrozole, letrozole or exemestane. See what exemestane is for and how to use it.

It is important to always inform the doctor or pharmacist of all medicines, natural products or supplements that are used, to avoid increasing or decreasing the effect of tamoxifen.