Older women who take an antidepressant seem to have a small but noteworthy increased risk of stroke and death compared to older women not on an antidepressant medication, a new study shows.

But given that depression itself is a well-established risk factor for early death, heart disease and other ills, the study’s author told Reuters Health, women who need to take these medications shouldn’t see the new findings as a reason to quit.

“Women should not stop taking the medications based on this one study,” Dr. Jordan W. Smoller of Massachusetts General Hospital in Boston said in an interview. “What our study does is give patients and doctors a little bit more information about the risk-benefit calculation for older women.”

Antidepressant use in the US has more than quintupled since the early 1990s, Smoller and his colleagues note in their report in the Archives of Internal Medicine.

So-called selective serotonin reuptake inhibitors (SSRIs) such as Prozac and Zoloft are now the first-line treatment for most patients, having replaced older medications called tricyclic antidepressants that may harm the heart.

But little is known about how SSRIs affect heart health, especially in postmenopausal women, who are at increased risk for both heart disease and depression.

To investigate, Smoller and his team looked at 136,293 women participating in the Women’s Health Initiative, an ongoing investigation of women’s health after menopause. None of the women were taking antidepressants at the study’s outset.

During follow-up, which lasted about six years, 5,496 of the study participants started taking antidepressants. While there was no association between antidepressant use and heart disease, the researchers did find that women taking SSRIs had a 45 percent increase in risk of stroke and a 32 percent increase in risk of dying from any cause during follow up, compared with nonusers. Use of older tricyclic antidepressants wasn’t linked to stroke, but it did increase by 67 percent the risk of death during follow up.

It’s important to remember, Smoller said, that these numbers represent “relative risk.” The actual risk of stroke or death for women taking the medications was higher than for women who weren’t using them, but it was still quite small.

For example, he explained, during a given year 0.8 percent of the women not using antidepressants would die, compared to 1.2 percent to 1.4 percent of the women taking the medications. And while 0.3 percent of women who weren’t taking SSRIs would have had a stroke in a typical year, 0.42 percent of women using SSRIs would suffer a stroke annually.

Another limitation to the findings, Smoller added, is that the effect observed with antidepressants could have been related to the fact that women who used the medications had other risk factors that couldn’t be completely accounted for - like being depressed.

The increased risk of death and stroke associated with depression itself, he added, is similar to that seen with the antidepressants used in the study.

No matter what, the researcher said, the relationship between antidepressants and death must be investigated further. “More than 10 percent of Americans are taking antidepressants,” he said. “It’s an important category of medication for us to understand better.”

SOURCE: Archives of Internal Medicine, December 14/28, 2009.