Efficacy of Oral Anticoagulants in Epilepsy and Atrial Fibrillation Not Impacted by Antiseizure Medications

Emily K. Acton, MSCE

A new study published in JAMA Neurology looked at how two types of antiseizure medications (ASMs) affect the effectiveness of direct-acting oral anticoagulants (DOACs) in patients with both epilepsy and atrial fibrillation (AF).¹ The study found that using enzyme-inducing (EI) ASMs did not change how well DOACs worked compared to non-EI ASMs. This finding is important because many people with epilepsy use EI ASMs, and it helps us understand how these medications interact with DOACs.

In the study, researchers found that there were 88.5 cases of blood clots for every 1,000 people who used DOACs and ASMs, and 68.3 cases of bleeding events in the same group. Although there was no increased risk of blood clots with EI ASMs, there was a lower risk of major bleeding events. This means that EI ASMs might reduce the chance of serious bleeding without affecting the chance of blood clots.

Emily K. Acton, a PhD student at the University of Pennsylvania, and her team said that previous studies had mixed results on this topic. Some suggested higher risks, while others showed no significant effects. Their study helps clarify the safety of using EI ASMs with DOACs for people with epilepsy and AF.

The researchers analyzed health data from patients with epilepsy and AF in the United States between October 2010 and September 2021. They looked at how patients using EI or non-EI ASMs with DOACs experienced blood clots and bleeding. They used special methods to account for various factors and to get accurate results.

Out of the patients studied, 3,619 were using EI ASMs, and 10,459 were using non-EI ASMs. Most of the patients using EI ASMs were older, mostly women, and White. Before matching patients by similar characteristics, those using non-EI ASMs were older and had more health problems.

The study has a few limitations. The data didn’t show how well patients stuck to their medication plans, and some details about why medications were prescribed were missing. Also, some patients were only followed for a short time, which might have affected the results. Certain medications not included in the study might have influenced the findings. Lastly, while the study included levetiracetam as a non-EI ASM, additional analyses confirmed the main results regarding its interaction with DOACs.

Overall, the study suggests that EI ASMs might lower the risk of major bleeding when used with DOACs, though further research is needed to understand this better and its impact on dosing DOACs for people with epilepsy and AF.

An original version of this article was published on sister site Neurology Live.

REFERENCES
^{1. Acton EK, Hennessy S, Gelfand MA, et al. Direct-Acting Oral Anticoagulants and Antiseizure Medications for Atrial Fibrillation and Epilepsy and Risk of Thromboembolic Events. JAMA Neurol. 2024;81(8):835-844. doi:10.1001/jamaneurol.2024.2057}