Montreal—Pharmacists and other healthcare professionals might want to raise some questions about prescriptions for selective serotonin reuptake inhibitors (SSRIs) in patients on oral anticoagulants (OACs) and vice-versa.

That is based on the findings of a new Canadian study, led by McGill University in Montreal, which identified an increased risk of major bleeding among atrial fibrillation (AFib) patients with concomitant use of the drugs compared with OAC use alone.

In a report in the Journal of the American Medical Association Network Open, the researchers reported on a nested case-control study involving 42,190 cases with major bleeding matched to approximately 1.2 million controls. Their findings suggest that concomitant SSRI and OAC use was associated with a 33% increased risk of major bleeding compared with OAC use alone. The study team also pinpointed that the risk was highest in the first few months of dual use but was substantially lower after 6 months.

“This study suggests that concomitant use of SSRIs and OACs may be a risk factor for bleeding and should be closely monitored, particularly within the initial months of treatment,” the study team concluded.

It is widely understood that SSRIs—commonly prescribed antidepressants—have been linked with a small increased risk of major bleeding. What was not previously known, however, was whether the risk of bleeding was increased with the combined use of SSRIs and OACs, the authors added.

The study team’s goal was not only to assess whether concomitant use of SSRIs with OACs is associated with an increased risk of major bleeding compared with OAC use alone, but it also sought to describe how the risk varies with duration of use and to identify key clinical characteristics modifying this risk.

The study was conducted among AFib patients from approximately 2,000 general practices in the United Kingdom contributing to the Clinical Practice Research Datalink. All of the participants initiated OACs between January 2, 1998, and March 29, 2021. The focus was on the effects of concomitant use of SSRIs and OACs, including direct OACs and vitamin K antagonists (VKAs), compared with OAC use alone.

Incidence rate ratios (IRRs) of hospitalization for bleeding or death due to bleeding were defined as the main outcome. The patients with major bleeding and those comprising the control group had similar mean ages of approximately 74 years, and an identical percentage (59.8) were men.

The results indicated that concomitant use of SSRIs and OACs was associated with an increased risk of major bleeding compared with OACs alone (IRR, 1.33; 95% CI, 1.24-1.42). “The risk peaked during the initial months of treatment (first 30 days of use: IRR, 1.74; 95% CI, 1.37-2.22) and persisted for up to 6 months,” the authors pointed out. “The risk did not vary with age, sex, history of bleeding, chronic kidney disease, and potency of SSRIs.”

They further explained, “An association was present both with concomitant use of SSRIs and direct OACs compared with direct OAC use alone (IRR, 1.25; 95% CI, 1.12-1.40) and concomitant use of SSRIs and VKAs compared with VKA use alone (IRR, 1.36; 95% CI, 1.25-1.47).”

Background information in the article advised that antidepressant medications are among the most frequently prescribed class of drugs worldwide, with up to 19% of individuals aged 60 years or older in the United States reporting use of an antidepressant over the past 30 days. The most widely used antidepressant medications are SSRIs, and those are often recommended over other classes of antidepressants for the treatment of major depressive disorder because of their comparable efficacy and favorable safety profile.

“However, SSRIs have been shown to increase the risk of major bleeding, possibly owing to their inhibition of platelet activation during hemostasis,” the researchers wrote. “Although the absolute risk remains low for most individuals who use SSRIs, co-prescription with drugs such as oral anticoagulants (OACs) may be consequential. Concomitant use of SSRIs and OACs is common given the prevalence of mental health disorders.”

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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