People with epilepsy often also have other medical conditions, including conditions that increase the risk of blood clots. Consequently, antiepileptic drugs (AEDs) are often prescribed with direct oral anticoagulants (DOACs), one of the main drugs used to prevent clot formation. However, some widely-used AEDs, called enzyme-inducing AEDs (EI-AEDs), may lower DOAC levels, increasing the risks of clots, stroke and pulmonary embolism. How often this interaction occurs is not clear. Most of the data on this potential problem comes from research conducted on bacteria, cell cultures, and laboratory research animals (such as mice), which does not necessarily tell us what will happen in humans. The few reports in humans are inconsistent, with some reporting an interaction, and some reporting no interaction. To help guide safe prescribing practices, we propose a large study of prescription and health care use records to: (1) examine patterns of prescription for AEDs with anticoagulants in adults with epilepsy; and, (2) determine whether there is a risk of serious health events from clot formation attributable to interactions between DOACs and EI-AEDs in adults with epilepsy.
