Did you know - Tamoxifen & antidepressants

[SoCalGal]

Hi - Just as an FYI - This was in today's Wall St Journal online. I was not aware of this info and know that many are on anti-d's and tamoxifen.


http://online.wsj.com/article/SB124390737596575037.html

The Food and Drug Administration is planning to warn doctors about an interaction between the widely used breast-cancer drug tamoxifen and certain antidepressants after a study showed women on both drugs were more than twice as likely to see their cancer return. The study involved about 1,300 women and was released this past weekend at the American Society of Clinical Oncology's annual meeting in Orlando, Fla. Researchers found that women who were taking antidepressants like Paxil, Prozac and Zoloft along with tamoxifen for at least one year had a breast-cancer recurrence rate of 16% -- compared with a recurrence rate of 7.5% for women not taking the drugs.
However, not all antidepressants strongly affect tamoxifen's usefulness, and the study showed that women on drugs like Celexa, Lexapro and Luvox didn't have a statistically higher rate of cancer recurrence.
Tamoxifen is an old but widely used treatment to prevent the return of breast cancers whose tumors were estrogen-dependent. This is one of the most common types of breast cancer.
The new study, which was led by researchers at Medco Health Solutions Inc., backs up prior laboratory studies that found drugs that interfere with an enzyme known as CYP2D6 also block the activation of tamoxifen. Antidepressants like Paxil and Prozac, which are also sold generically, are considered moderate-to-potent CYP2D6 inhibitors, while other commonly used antidepressants are considered weak CYP2D6 inhibitors.
Larry Lesko, director of the FDA's Office of Clinical Pharmacology, said now that the agency has evidence about clinical outcomes as a result of the drug interaction, the FDA is likely to add that information to tamoxifen's label. Placing information on FDA-approved drug labels is the main vehicle the agency uses to communicate with health-care professionals.
Julie Gralow, an associate professor in the oncology division of the University of Washington School, said she'd already been prescribing Wyeth's Effexor, which also doesn't appear to interfere with tamoxifen, primarily for the treatment of hot flashes that are a side effect of tamoxifen.
"This is what you'd predict," she said of the study, which also involved researchers at Indiana University School of Medicine.
"If we lower the effectiveness of tamoxifen, you'd get worse outcomes." Dr. Gralow said many doctors in the U.S. also prescribe aromatase inhibitors rather than tamoxifen to block estrogen in post-menopausal women to prevent breast cancer from returning, which also avoids the tamoxifen-antidepressant interaction.
Still, Robert Epstein, Medco's chief medical officer, said more than 500,000 women in the U.S. are taking tamoxifen and about 30% of those women are also prescribed antidepressants. He said Medco has been notifying doctors when it sees patients in its pharmacy-benefits database being given tamoxifen and an CYP2D6 inhibitor drug like tamoxifen, and found that some breast-cancer doctors weren't aware that another doctor had prescribed an antidepressant.