MONDAY, Sept. 26 (HealthDay News) -- Heart attack patients who take both selective serotonin reuptake inhibitor (SSRI) antidepressants and antiplatelet drugs such as aspirin or Plavix have a higher risk for bleeding than those who take anti-clotting drugs only, a new study finds.

Commonly prescribed SSRIs include Zoloft, Prozac, Paxil and Lexapro.

Antiplatelet drugs prevent blood cells from sticking together and forming a blood clot. Heart attack patients are commonly prescribed antiplatelet therapy to reduce their risk of another heart attack. But there's an increased risk of bleeding, which increases even further when certain other drugs are taken at the same time.

It so happens that many heart attack patients have depression symptoms and are prescribed antidepressants, noted the researchers at McGill University in Montreal.

"We're always concerned about how other medicines might interact with the medicines we know are essential to heart health and recovery after heart attack," said Dr. Kirk Garratt, clinical director of interventional cardiovascular research at Lenox Hill Hospital in New York City. "Although SSRIs are used in only a few cardiac patients, learning that SSRIs can increase [the] risk of bleeding complications could have important implications for how we care for patients after stents and other heart procedures."

In the Canadian study, the researchers looked at more than 27,000 heart attack patients, aged 50 and older, and found that patients taking aspirin or Plavix alone had a similar risk of bleeding. But taking an SSRI antidepressant and aspirin increased the risk of bleeding by 42 percent, and taking an SSRI with both aspirin and clopidogrel (dual antiplatelet therapy) increased the risk by 57 percent.

Bleeding included gastrointestinal bleeding, hemorrhagic stroke or other bleeding that required hospitalization or occurred in the hospital during treatment.

The researchers also found that the risk of bleeding was lower in women and in patients who had angioplasty after their heart attack.

The study appears Sept. 26 in the Canadian Medical Association Journal.

"Ultimately, clinicians must weigh the benefits of SSRI therapy against the risk of bleeding in patients with major depression following acute myocardial infarction," the researchers wrote in a journal news release.

They urged doctors to be cautious when prescribing antidepressants to heart attack patients on antiplatelet therapy.

More information

The Texas Heart Institute has more about antiplatelet therapy.