Some Antidepressants Interact with Tamoxifen

Several Antidepressants Cancel Out the Anti-Estrogen Effects of Hormone Therapy

Tamoxifen is a hormone therapy drug taken by many premenopausal women after completing their initial treatments for estrogen-sensitive breast cancer. To treat the side effects of Tamoxifen and to help with depression, doctors often prescribe antidepressants. However, research shows that some of these drugs can cancel out the benefits of Tamoxifen, and should be avoided.

Once a young woman is past surgery, chemotherapy, and radiation therapy, she may need to take Tamoxifen for five years to block estrogen receptors in breast tissue and prevent a recurrence of cancer.

In some cases, Tamoxifen may be given to women at high risk for breast cancer as an effort to forestall or prevent the development of a breast tumor.

The side effects of Tamoxifen often include menopausal symptoms, such as hot flashes, low libido, vaginal dryness, and osteoporosis. In rare cases, some women experience endometrial cancer, cataracts, and circulatory problems. In addition, many women who have been treated with chemotherapy for estrogen-receptor positive breast cancer develop some depression during or after primary treatment. You may not develop these problems, but you should be aware of them and discuss these side effects with your doctor if these appear.

Here is a table of antidepressants that may affect the benefits of tamoxifen in women with estrogen-receptor positive breast cancer.

Antidepressants And How They Interact With Tamoxifen

Antidepressant DrugInteraction with TamoxifenSafety Range

Paxil (paroxetine)

Prozac (fluoxetine)

Prevents antiestrogen benefitAvoid Use

Cymbalta (duloxetine)

Wellbutrin (bupropion)

Zoloft (sertraline)

Medium interference with antiestrogen benefit

Note: Studies confirm that Zoloft interferes with Tamoxifen.

Increases Risk
Saint John's Wort
Modest inhibition of antiestrogen benefitIncreased Risk

Celexa (citalopram)

Lexapro (escitalopram)

Pristiq (desvenlafaxine)

Remeron (mirtazapine)

Mild interaction

Note: Pristiq and Remeron have not been well-studied for interaction with Tamoxifen.

Slight Risk
Black Cohosh
May enhance the antiestrogen benefit

Note: There are just a few studies for interaction with Tamoxifen.

Slight Risk

Effexor (venlafaxine)

Almost no interaction with TamoxifenBest Choice

Black Cohosh. Kligler, B. Albert Einstein College of Medicine, New York. Am Fam Physician. 2003 Jul 1;68(1):114-116.

Interactions between tamoxifen and antidepressants via cytochrome P450. Desmarais JE, et al. Journal of Clinical Psychiatry (Dec. 2009): Vol. 70, No. 12, pp. 1688-97.

Tamoxifen treatment and new-onset depression in breast cancer patients. Lee KC, Ray GT, Hunkeler EM, Finley PR. Psychosomatics. 2007 May-Jun;48(3):205-10.