A common antidepressant weakens or cancels the beneficial effects of a standard treatment for breast cancer, according to the recent study. Women who take the mood drug paroxetine – better known its brand name Paxil and Seroxat – at the same time as the breast cancer medication tamoxifen face an increased risk of death., researcher reported.
The antidepressant alone has no impact on the course of the disease but should not be taken at the same time as anticancer drug, the study recommended.
Tamoxifen significantly improves survival for the dominant type of breast cancer, the most diagnosed cancer in women worldwide.
But to work properly, it must be converted by the liver into an active metabolite, the chemical remains after a drug broken down by the body.
It was previously suspected that antidepressant that boost the release of the natural occurring neutransmitter serotonin, such as paroxetine, might interfere with this process.
Canada investigated the health care records of 2,430 women with breast cancer who had received tamoxifen from 1993 to 2005.
About 30% of these women also received antidepressant – paroxetine more than any other – at the same time, often prescribed over long periods to help patient cope with the stress battling the deadly disease.
The use of paroxetine in combination with tamoxifen resulted in an increased long term risk of breast cancer death – approximately one additional fatality after 5 years of illness for every 20 women treated.
Tamoxifen is prescribed to women who so – called estrogen receptors positive breast cancer, which accounts for up to 80% of all cases of the disease.
