What medications can be used to treat hot flushes in premenopausal women receiving tamoxifen for breast cancer?

Tamoxifen (Nolvadex, generics), which blocks the effects of estrogen on breast and other tissue, is often used in the adjuvant treatment of hormone receptor-positive breast cancer in premenopausal women. Hot flushes are a frequent side effect. While women without breast cancer can use estrogen or progesterone to manage their hot flushes, these hormones are not used in cancer patients because of the risk that they will stimulate hormone-positive breast cancers. Studies in this population have found that estrogen and progesterone use more than doubles the risk of recurrence. Therefore, other medications are used to manage hot flushes whenever possible.

No treatment option controls hot flushes in every woman. Therefore, nurses should encourage patients to communicate with their oncologist if their current hot flush medication is not working. Some antidepressants, specifically the selective serotonin reuptake inhibitors (SSRIs) (eg, fluoxetine) and serotonin and norepinephrine receptor inhibitors (SNRIs) (eg, venlafaxine [Effexor, generics]), are effective in managing hot flushes in many women. Studies of venlafaxine, fluoxetine, and citalopram (Celexa, generics) have reported fewer hot flushes in women taking these medications. Women receiving tamoxifen should not take paroxetine (Paxil, Pexeva) because it interferes with the metabolism of tamoxifen to its active form. Other antidepressants produce this effect to a lesser degree, and venlafaxine does not seem to interfere at all.

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Gabapentin (Gabarone, Gralise, Neurontin, generics) and clonidine (Catapres, generics) have also been studied in the treatment of hot flushes. While both these medications are effective in some women, clonidine is not often used because of side effects, including drowsiness, dizziness, and dry mouth.

In addition to lifestyle modifications, such as dressing in layers and avoiding spicy foods, some vitamins and herbs have been purported to manage hot flushes. However, a randomized trial of vitamin E showed that it was no better than placebo in controlling hot flushes. Black cohosh, phytoestrogens, and other herbs have weak estrogenic properties and should not be used in women with a history of breast cancer. Women who wish to use herbal therapy for managing hot flushes should discuss the possible effects with their oncologist. ONA

Lisa Thompson is assistant professor, Department of Clinical Pharmacy, University of Colorado Denver School of Pharmacy, Aurora, Colorado.