SSRI increases bleeding risk after MI

Patients who received a selective serotonin reuptake inhibitor (SSRI) after acute myocardial infarction were at higher risk of bleeding, a new study found.

The retrospective cohort study included 27,000 patients discharged from a Canadian hospital following an acute myocardial infarction (MI). All of the patients were taking some form of antiplatelet therapy: 14,426 were on aspirin (ASA), 2,467 received clopidogrel and 9,475 took both. Some of the patients also received an SSRI in combination with aspirin (406 patients), with clopidogrel (45) or both (239). The study followed the patients until death, readmission due to bleeding or repeat MI, or the end of the study period.

The addition of the SSRI to the antiplatelet regimens was associated with an increased risk of bleeding, researchers found. Compared to patients taking only aspirin, patients in the ASA plus SSRI group had a 42% increased risk of bleeding (95% confidence interval [CI] for hazard ratio, 1.08 to 1.87). The use of an SSRI, aspirin and clopidogrel all together increased risk by 57% compared to just dual antiplatelet therapy (95% CI for hazard ratio, 1.07 to 2.32). The study also found a higher bleeding risk in patients taking clopidogrel with an SSRI than those on clopidogrel alone, but the patient population was too small to prove significance.

The study authors noted that previous studies have reported increased bleeding with SSRIs that have a higher affinity to serotonin, a finding that was not replicated by this research. This study was limited by its observational nature, reliance on billing information, and lack of data on compliance with medication regimens. Still, the authors concluded that physicians should cautiously weigh the benefits of SSRI therapy against the risk of bleeding in post-MI patients with major depression. The study was published online by the Canadian Medical Association Journal on Sept. 26.