Lamotrigine and Cardiac Arrhythmias: A Target Trial Approach.

Area of Science:

• Neurology
• Cardiology
• Pharmacology

Background:

• Lamotrigine is a widely used antiseizure medication (ASM) known for its efficacy and tolerability.
• A recent safety warning suggested a potential link between lamotrigine and ventricular arrhythmias (VT/VF).
• Levetiracetam was chosen as a comparator due to its presumed cardiac inertness.

Purpose of the Study:

• To compare the incidence of ventricular arrhythmias (VT/VF) in patients newly treated with lamotrigine versus levetiracetam for seizures.
• To investigate the cardiac safety profile of lamotrigine in a real-world setting.

Main Methods:

• Retrospective cohort studies were conducted using two large datasets: Medicare (US) and Clinical Practice Research Datalink (CPRD, UK).
• Patients initiating lamotrigine or levetiracetam as their first ASM were identified and followed for 2 years.
• Cox proportional hazard models were used to compare the cumulative incidence of VT/VF between the two groups, adjusting for relevant covariates.

Main Results:

• The study included over 53,000 patients across both datasets.
• After adjusting for demographics and comorbidities, the hazard ratio for VT/VF comparing lamotrigine to levetiracetam was not statistically significant in either Medicare (0.73) or CPRD (0.75).
• The 2-year cumulative incidence of VT/VF was similar between groups, with lamotrigine showing a slightly lower, though not statistically significant, incidence in both datasets.

Conclusions:

• The findings do not support concerns that lamotrigine increases the risk of ventricular arrhythmias.
• Lamotrigine appears to be a safe option regarding cardiac arrhythmias when initiated as a first-line ASM.
• Further research may be needed to address potential residual confounding and generalizability to diverse populations.