Dysarthria and visual hallucinations due to flecainide toxicity

Area of Science:

• Cardiology
• Clinical Pharmacology
• Neuroscience

Background:

• Recurrent ventricular tachyarrhythmias post-myocardial infarction (MI) are often managed with antiarrhythmic drugs.
• Flecainide is a Class Ic antiarrhythmic agent used to treat ventricular arrhythmias.
• Drug toxicity can lead to significant adverse events, necessitating careful patient monitoring.

Observation:

• A 65-year-old male patient presented with dysarthria and visual hallucinations.
• These neurological symptoms were attributed to flecainide toxicity.
• The patient had a history of myocardial infarction and recurrent ventricular tachyarrhythmias.

Findings:

• Flecainide toxicity can manifest with central nervous system side effects, including dysarthria and visual hallucinations.
• Serum flecainide level estimation is essential for diagnosing and managing toxicity.
• Patients with compromised renal or hepatic function are at increased risk of flecainide accumulation and toxicity.

Implications:

• The case highlights the importance of therapeutic drug monitoring for flecainide.
• A readily available assay for serum flecainide levels is needed, particularly for vulnerable patient populations.
• Optimizing flecainide dosing and monitoring can prevent severe adverse events and improve patient outcomes in arrhythmia management.