Lamotrigine use not linked to increased risk of cardiac morbidity and mortality

Denmark: A new study reports that lamotrigine use is associated neither with the risk of cardiac conduction disorders in people without pre-existing cardiac morbidity nor with all-cause mortality in people with pre-existing cardiac morbidity. The article was published in Epilepsia.

Recently, the US FDA issued a warning against the use of Lamotrigine in people at risk of cardiac rhythm and conduction abnormalities. Lamotrigine is one of the most widely used antiseizure medications for epilepsy and bipolar disorders. The warning was issued after an in vitro study showed that lamotrigine may slightly inhibit cardiac sodium channels, giving rise to class IB antiarrhythmic activity. Also, there is concern that it may slow ventricular conduction and thus increase the risk of proarrhythmia and sudden death in people with structural or functional heart disease. Therefore, the lamotrigine label warns about its use in patients with cardiac conduction disorders (e.g., second or third-degree heart block), ventricular arrhythmias, and cardiac disease or abnormality. Concerns about the safety of treatment are central to the management of illness in people with epilepsy and bipolar disorder treated with lamotrigine. It is essential to address these concerns.

Christensen. J, Aarhus University Hospital, Denmark, and colleagues initiated a study to assess the risk of cardiac morbidity and mortality in new users of lamotrigine.

Researchers followed 91 949 members aged ≥15 for the first 2 years after initiating lamotrigine therapy. Among the new users 86 769 had no pre-existing cardiac disease and n = 5180 had pre-existing cardiac disease. The main outcomes were set as cardiac conduction disorders in people without pre-existing cardiac morbidity and all-cause mortality in people with pre-existing cardiac morbidity. Cox proportional hazards models were used for hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for comparison of the risk in current versus past users of lamotrigine.