New Study: Antidepressants Commonly Prescribed with Tamoxifen Put Women at Much Higher Risk for Recurrent Bre...( - Several SSRIs more than double risk...),Health

- Several SSRIs more than double risk of cancer recurrence in tamoxifen treated patients

- Nearly 30 percent of tamoxifen users take drugs that reduce its effectiveness against breast cancer

ORLANDO, Fla., May 30 /PRNewswire-FirstCall/ -- An important new study finds that certain popular antidepressants frequently prescribed to women taking the breast cancer drug tamoxifen more than double the risk of a breast cancer recurrence for those using both medications. The research presented by Medco Health Solutions, Inc. (NYSE: MHS) and Indiana University School of Medicine at the 2009 Annual Meeting of the American Society of Clinical Oncology (ASCO) is the largest study to date looking at how these drugs impact breast cancer recurrence rates when taken with tamoxifen.

The antidepressants at issue are three widely used selective serotonin reuptake inhibitors (SSRIs), Prozac(R) (fluoxetine), Paxil(R) (paroxetine) and Zoloft(R) (sertraline), and are among a group of drugs known as CYP2D6 inhibitors. Antidepressants are often prescribed with tamoxifen to treat depression - a common co-morbidity of the disease, as well as hot flashes - a common side-effect of the breast cancer drug.

The three drugs that pose this risk for women on tamoxifen are considered to be moderate to potent CYP2D6 inhibitors. Several other SSRIs examined in the study that are weak CYP2D6 inhibitors did not raise breast cancer recurrence risks for patients using them along with tamoxifen. Those SSRIs included Celexa(R) (citalopram), Lexapro(R) (escitalopram) and Luvox(R) (fluvoxamine).

"We've known that these CYP2D6 inhibitor drugs block the activation of tamoxifen chemically, but this is the first time there's evidence that these drugs are putting women at a much higher risk for recurrent breast cancer
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