A commonly prescribed antidepressant may counter the effectiveness of breast
cancer medications and increase a woman's risk of death, a new study has
found.
Paxil, an antidepressant often prescribed to women with breast cancer, could
decrease - or completely destroy - the effects of tamoxifen, a widely used
and extremely effective breast cancer drug.
"For women taking these two drugs together, I think there are better options
for the treatment of depression," said Dr. David Juurlink, a senior
scientist at
the Institute for Clinical Evaluative Sciences in Toronto and one of the
study's authors.
According to the Canadian Breast Cancer Foundation, about 22,700 women and
180 men are diagnosed with breast cancer every year in Canada.
Nearly half of all breast cancer patients develop depression within the
first year, and 25% in the third and fourth, according to the British
Medical Journal.
Many of these patients are prescribed selective serotonin reuptake
inhibitors (SSRIs), a drug class that includes paroxetine, meaning Paxil
and its generics.
The study looked 2,430 women in Ontario, aged 66 and up, who were treated
with both tamoxifen and an SSRI between 1993 and 2005. Of those, 374, or
15%, had died of breast cancer.
On average, these patients were taking antidepressants for about half the
time they were on tamoxifen, a drug therapy that usually lasts five years.
The longer both drugs were combined, the greater the risk of death, the
study found.
