How does lacosamide affect the heart?

How does lacosamide change heart rhythm in people with epilepsy?

Lacosamide slows electrical conduction through the heart by blocking sodium channels that also exist in cardiac muscle cells. This action can lengthen the PR interval on an ECG, which measures the time between the start of the P wave and the QRS complex. Studies show average PR-interval increases of 3–12 ms, and some patients reach first-degree atrioventricular block. The effect is dose-related and appears more often at daily doses above 400 mg.

What heart risks increase when lacosamide is combined with other drugs?

Adding lacosamide to sodium-channel blockers such as carbamazepine or lamotrigine can further slow conduction and raise the chance of second- or third-degree heart block. Beta-blockers, calcium-channel blockers, and certain anti-arrhythmics intensify the same risk. Patients taking these combinations need ECG monitoring before and after dose increases.

Who should avoid lacosamide because of heart concerns?

People with known second- or third-degree atrioventricular block, sick-sinus syndrome without a pacemaker, or severe conduction disorders should not start lacosamide. Those with recent myocardial infarction or heart failure also face higher risk. A baseline ECG is recommended for anyone over 65 or with a history of conduction abnormalities.

Can lacosamide cause dangerous heart rhythms?

Although rare, lacosamide has been linked to atrial fibrillation, atrial flutter, and ventricular arrhythmias in post-marketing reports. The FDA label carries a warning for these events, particularly in patients with structural heart disease. Sudden cardiac events remain uncommon but require immediate evaluation if dizziness, fainting, or palpitations occur.

When does the heart effect appear and how long does it last?

PR-interval changes begin within days of reaching a stable dose and usually remain stable during long-term treatment. The effect reverses within days to weeks after stopping the drug. No cumulative toxicity on conduction has been observed in open-label extension studies lasting several years.

How do doctors monitor heart safety during lacosamide treatment?

An ECG is obtained before starting therapy and repeated whenever the dose is raised or new symptoms appear. Blood-pressure and heart-rate checks occur at each visit. Patients are advised to report any chest pain, shortness of breath, or fainting immediately.