Electrocardiographic Evaluation in Patients Receiving Lamotrigine Monotherapy/Duotherapy

Objective:Despite its widespread use and safety data, the cardiac safety of lamotrigine was brought into question in October 2020 when the U.S. Food and Drug Administration issued a safety warning about its cardiac side effects. Here, we investigated whether there are differences in electrocardiogram (ECG) findings between epilepsy cases receiving lamotrigine monotherapy and those receiving duotherapy.Methods:Patients older than 16 years who were followed up with a diagnosis of epilepsy and receiving lamotrigine were retrospectively identified. Those receiving only lamotrigine and any second anti-seizure medication (ASM) in addition to lamotrigine were included in the study, and those receiving more than two ASMs were excluded. Eligible patients were asked to apply to any health institution and have an ECG performed. Heart rate, PR distance, QRS duration, QT duration, corrected QT value, and Tp-Tend value were calculated manually, and ST-T changes were evaluated. Comparisons were made between patients receiving monotherapy and dootherapy and those receiving low-dose and high-dose lamotrigine.Results:There were 19 patients receiving monotherapy and 11 receiving duotherapy. The ECG parameters of all other patients were within normal values. When ECG parameters were compared between patients receiving monotherapy and those receiving duotherapy, no significant differences were found in heart rate, PR distance, QRS duration, QT duration, QTc duration, Tp-Tend duration, and presence of ST-T changes. When the patients were divided into low-dose and high-dose lamotrigine groups, there were no significant differences in the ECG parameters between these two groups.Conclusion:The relationship between the use of lamotrigine and cardiac conduction problems in patients with epilepsy has attracted the attention of physicians since its introduction into clinical practice. Although our results did not indicate a significant relationship, there is still a need to determine the risk groups and clarify the pathophysiology of lamotrigine-related arrhythmia through genotype- and phenotype-related studies.