New test suggests antidepressant Paxil may promote breast cancer

A team of researchers from the City of Hope in Duarte has developed a speedy way to identify drugs and chemicals that can disrupt the balance of sex hormones in human beings and influence the development and progress of diseases such as breast cancer.

In a trial screening of 446 drugs in wide circulation, the new assay singled out the popular antidepressant paroxetine (better known by its commercial name, Paxil) as having a weak estrogenic effect that could promote the development and growth of breast tumors in women.
This is important because as many as a quarter of women being treated for breast cancer suffer from depression -- a condition most commonly treated with antidepressants known as SSRIs (selective serotonin reuptake inhibitors), including Paxil, which has been on the market since 1992. Almost a quarter of American women in their 40s and 50s are taking an antidepressant, mostly SSRIs.

Last summer, the Food and Drug Administration approved the marketing of a low dose of paroxetine -- repackaged under the commercial name Brisdelle -- as a nonhormonal treatment for hot flashes and other menopausal symptoms.

About 70% of breast cancers in women are sensitive to estrogen, meaning that the hormone found plentifully in females of child-bearing age contributes to their growth.

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