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Home > Understanding Breast Cancer > Treatment > Side Effects of Tamoxifen


Side Effects of Tamoxifen


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If you have hormone receptor-positive breast cancer, hormone therapy with tamoxifen and/or an aromatase inhibitor is a key part of your treatment.  

Compared to chemotherapy, tamoxifen has few side effects. For example, tamoxifen does not cause hair loss. However, menopausal symptoms, like hot flashes, are common in women who take tamoxifen [62]. Although these symptoms may become less frequent and less intense over time, they can still be hard to manage. If you have any symptoms, talk to your health care provider. He/she can help treat many of them.  

The most serious health risks of tamoxifen, such as endometrial cancer (cancer of the lining of the uterus) and blood clots in the lungs, are very rare [62].  

Figure 5.10 lists some possible side effects and health risks of tamoxifen in women. 

 Figure 5.10: Side effects and health risks of tamoxifen in women 


  • Hot flashes and night sweats
  • Vaginal discharge
  • Vaginal dryness or itching
  • Irregular periods or spotting (uterine bleeding)

Less common 

  • Loss of sex drive 


  • Blood clots in the large veins (deep venous thrombosis)
  • Blood clots in the lungs (pulmonary emboli)
  • Bone loss (premenopausal women only)
  • Cancer of the uterus (uterine or endometrial cancer)
  • Cataracts
  • Stroke 
Adapted from National Cancer Institute materials [62].

In men, possible side effects include [62-63]:

  • Headache
  • Hot flashes
  • Impotence
  • Loss of sex drive
  • Nausea and vomiting
  • Skin rash

Side effects of tamoxifen versus side effects of aromatase inhibitors

Although both aromatase inhibitors and tamoxifen can cause menopausal symptoms such as hot flashes, many of their side effects differ. Learn more about how the side effects of these hormone therapies compare.


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Health benefits of tamoxifen beyond breast cancer treatment

In addition to treating breast cancer, tamoxifen has other health benefits. Tamoxifen may:

  • Improve your blood cholesterol profile by lowering LDL levels (the "bad" cholesterol). A better cholesterol profile may lower your risk of heart disease.
  • Help maintain bone density and thus, lower your risk of osteoporosis and bone fractures (in postmenopausal women).

Tamoxifen as a risk-lowering drug

Cancer-free women who have a high risk of developing breast cancer (including those with atypical hyperplasia or lobular carcinoma in situ) can take tamoxifen to lower their risk [61].  

Learn more about risk-lowering drugs and other options for women at high risk of breast cancer

Updated 04/26/14

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previous  Tamoxifen 
Aromatase Inhibitors  next 
Side Effects of Aromatase Inhibitors  next 
Ovarian Suppression  next 
Emerging Areas in Chemotherapy, Hormone Therapy and Targeted Therapy  next 
Questions for Your Provider – Hormone Therapy  next