Side Effects Of Tamoxifen

Side Effects Of Tamoxifen

Estrogen Receptor Positive Breast Cancer is a form of breast cancer that is caused by the increased sensitivity of certain protein structures present on the surface of the cancer cells to circulating estrogen in the body. These protein structures would stimulate the cancer cells to divide rapidly every time they come in contact with estrogen.

Figure 5.9 below shows how tamoxifen works. Tamoxifen attaches to the hormone receptor in the cancer cell, blocking estrogen from attaching to the receptor. This slows or stops the growth of the tumor by preventing the cancer cells from getting the hormones they need to grow.

And so patients who are diagnosed with estrogen receptor positive breast cancer would need to undergo treatments and medications that aim at reducing the estrogen levels in the body, an action that would effectively prevent the division of the cancer cells.

Tamoxifen and Breast Cancer

Also called as Nolvadex, Tamoxifen is a medication that is prescribed for patients who are undergoing treatment for estrogen receptor positive breast cancer. The medication effectively helps to prevent the recurrence of this type of breast cancer.

Possible Side Effects of Tamoxifen

Every single medication out there would have some side effect or the other on the body. And Tamoxifen is no different. The drug can potentially cause a series of side effects that can be more troublesome for some individuals while others would be able to tolerate these minor symptoms.

Uterine sarcomas

Uterine sarcomas are a rare form of cancer, accounting for only 8% of uterine cancers.

Despite the low mortality rate from endometrial cancer in women on tamoxifen, and the improvement in the 5-year survival ofwomen with breast cancer who are on tamoxifen adjuvant therapy, there remains a statistically significant rise in the number of endometrial cancers and deaths from this cause after approximately 5 years on tamoxifen, as compared to placebo.

Menopausal Symptoms

The most common side effects experienced by women who take Tamoxifen are symptoms that resemble those experienced bywomen during menopause.

Some of the more common side effects of the drug in this case would include vaginal drynessirregular menstrual periods, low libido, nausea, and weight loss, Tamoxifen could also lead to the early onset of menopause in women who are near that particular stage of their lives.


Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.

This drug should not be used with the following medications because very serious interactions may occur: anastrozole, letrozole.if you are currently using any of these medications listed above, tell your doctor or pharmacist before starting tamoxifen.

Serious Side Effects of Tamoxifen

Tamoxifen can cause some serious side effects in the body as well. In case you start noticing any abnormal signs or symptoms related to the effects mentioned below, check the same with a doctor for further course of action.

Accordingly some of the more uncommon but serious side effects of Tamoxifen in women include formation of new tumors, noticeable increase in the size of the tumor, severe depression, respiratory issues, breathlessness, abnormal vaginal bleeding, severe chest pain, high blood pressure, appearance of blood clots (indicated by pain, swelling and a feeling of tenderness in the area), osteoporosis (including broken bones), severe allergic reactions (including rashes, hives, swelling, and skin irritation), increased risk of endometrial or uterine cancer, and permanent uterine changes (non cancerous).

Important Points to Ponder

These side effects may vary from individual to individual. So while one woman can experience none of these symptoms, another can experience a group or all of these side effects at the same time. It is considered absolutely essential to discuss the pros and cons of taking Tamoxifen with a qualified medical practitioner before starting the course.