Related Experiment Video
Updated: May 2, 2026

Behavioral Characterization of Pentylenetetrazole-induced Seizures: Moving Beyond the Racine Scale
Published on: July 8, 2025
Flecainide-induced myoclonus
Sara Llamas Velasco1, Fernando Sierra-Hidalgo, Rosa María Ceballos Rodríguez
1*Neurology Department, Hospital Universitario 12 de Octubre, Madrid, Spain; and †Instituto de Investigación Hospital 12 de Octubre (i + 12), Madrid, Spain.
Abstract:
Flecainide is a class 1c antiarrhythmic that acts by blocking sodium channels to reduce intracardiac conduction and is used mainly in the treatment of supraventricular arrhythmias. Dizziness, visual disturbances, headache, and nausea are commonly associated with flecainide, but severe central nervous system toxicity is rare. Here, we report the case of a 71-year-old woman with a history of renal transplantation who developed severe myoclonus 24 hours after being started on flecainide, 100 mg 2 times a day, because of atrial fibrillation. This symptom completely disappeared once the drug was removed. Only 2 patients presenting with flecainide-induced myoclonus have been previously reported. Although the exact pathophysiologic explanation of this phenomenon remains unclear, it is well known that the susceptibility to severe flecainide toxicity is increased in patients with chronic kidney disease.
Related Concept Videos
Antiepileptic Drugs: Potassium Channel Activators
Ezogabine has gained approval as an adjunctive treatment...
Seizures ll: Types
Antiepileptic Drugs: Glutamate Antagonists
Skeletal Muscle Relaxants: Adverse Effects
Unlike...
Antiepileptic Drugs: GABAergic Pathway Potentiators
The key GABA pathway potentiators used in epilepsy management are as follows.
Benzodiazepines are a well-known class of drugs used for...
Antiepileptic Drugs: Sodium Channel Blockers
Sodium channel blockers modulate ion channels, particularly voltage-gated sodium channels. They block only sodium ion movement.
Among the most commonly prescribed antiepileptic drugs are...

