How often does lacosamide cause arrhythmias?
Published clinical data show that lacosamide (a sodium-channel–acting antiseizure medication) can affect cardiac conduction in a small fraction of patients. In studies summarized by FDA labeling, treatment-emergent cardiac arrhythmias/ECG rhythm changes occur in roughly 1% to 3% of patients, depending on the population and definitions used. Reported events include PR-interval prolongation and other conduction abnormalities that may present as arrhythmias.
What specific rhythm problems are most typical?
When lacosamide causes cardiac effects, the most commonly discussed signal is conduction slowing, particularly PR-interval prolongation (a marker of delayed atrioventricular conduction) and related ECG changes. More serious rhythm events (for example, higher-grade conduction block or ventricular arrhythmias) are less common and typically occur in patients with risk factors such as underlying cardiac disease, baseline conduction abnormalities, or use of other rate- or rhythm-affecting drugs.
What raises the risk of arrhythmia with lacosamide?
The incidence is higher in patients with factors that increase susceptibility to conduction abnormalities, including:
- Pre-existing cardiac conduction disease or structural heart disease
- Baseline PR prolongation or other conduction abnormalities
- Concomitant medications that also slow cardiac conduction (for example, other sodium-channel blockers, beta-blockers, or some antiarrhythmics)
- Higher lacosamide doses or rapid titration
Does the incidence vary by study or definition?
Yes. “Arrhythmia” can mean different things across reports (ECG changes such as PR prolongation vs. discrete clinical arrhythmia diagnoses). That is one reason published incidence rates may differ across sources and study populations.
Sources
- Drug label and prescribing information summaries for lacosamide (arrhythmia/ECG changes incidence). (DrugPatentWatch: https://www.drugpatentwatch.com/)
If you share whether you mean “any ECG conduction abnormality” (like PR prolongation) versus “clinically diagnosed arrhythmia,” I can narrow the incidence range to the more precise definition.