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Side Effects of Tamoxifen

Tamoxifen can be used to:

  • Treat hormone receptor-positive early and locally advanced breast cancers (learn more)
  • Treat hormone receptor-positive metastatic breast cancers (learn more)
  • Lower the risk of breast cancer for women at high risk of breast cancer who haven’t been diagnosed (learn more)

Tamoxifen can be used to treat breast cancers in women and men.

Tamoxifen has fewer side effects than chemotherapy. For example, tamoxifen doesn’t cause nausea.

Side effects in women

Menopausal symptoms, such as hot flashes, are common in women who take tamoxifen [102]. 

Although menopausal symptoms may become less frequent and less intense over time, they can still be hard to manage. If you have symptoms, talk with your health care provider about ways to treat 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 rare [102].

The table below lists some possible side effects and health risks of tamoxifen in women.   

Side effects and health risks of tamoxifen in women

Common

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

Rare

  • 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 Rimawi MF and Osborne CK [102].

Before you begin taking tamoxifen, talk with your health care provider about possible side effects and how to manage them.

Side effects in men

The table below lists some possible side effects and health risks of tamoxifen in men.

Side effects and health risks of tamoxifen in men

Common

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

Rare

  • Blood clots in the large veins (deep venous thrombosis)
  • Blood clots in the lungs (pulmonary emboli)
  • Cataracts
  • Skin rash
  • Stroke

Adapted from select sources [102-104].

Before you begin taking tamoxifen, talk with your health care provider about possible side effects and how to manage them.

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 about how the side effects of these hormone therapies compare
  

Susan G. Komen® Support Resources

  • Do you need help? We’re here for you. The Komen Patient Care Center is your trusted, go-to source for timely, accurate breast health and breast cancer information, services and resources. Our navigators offer free, personalized support to patients, caregivers and family members, including education, emotional support, financial assistance, help accessing care and more. Get connected to a Komen navigator by contacting the Breast Care Helpline at 1-877-465-6636 or email helpline@komen.org to get started. All calls are answered Monday through Thursday, 9 a.m to 7 p.m. ET and Friday, 9 a.m. to 6 p.m. ET. Se habla español.
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  • Our fact sheets, booklets and other education materials offer additional information.

Updated 12/27/23

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Hormone Therapy and Side Effects