New research suggests that selective serotonin reuptake inhibitors (SSRIs) may increase risk of bleeding, transfusion, hospital readmission at 30 days, and death when taken around the time of surgery. The study appears in the April 29, 2013, issue of JAMA Internal Medicine.

Researchers led by Andrew D. Auerbach, MD, MPH, of the University of California, San Francisco, reviewed the medical records of more than 530,000 patients who underwent surgery at 375 US hospitals between 2006 and 2008. They retrospectively matched patients who had taken SSRIs with patients who were not taking the drugs. After matching and controlling for variables such as age, gender, medical condition, and depression, they found that patients on SSRIs still were about 10% more likely to experience bleeding, the need for transfusion, hospital readmission, and death when they took this medication around the time of surgery.

Exactly how, or if, SSRIs increase these risks is not fully understood, but they are known to interfere with the functioning of platelets.

“Receiving SSRIs in the perioperative period is associated with a higher risk for adverse events. Determining whether patient factors or SSRIs themselves are responsible for elevated risks requires prospective study,” the study authors conclude.