Ocular Side Effects of Flecainide
Yes, flecainide commonly causes visual disturbances, occurring in approximately 16-28% of patients, making it one of the most frequent non-cardiac adverse effects of this medication. 1, 2
Nature and Frequency of Visual Side Effects
Visual disturbances represent the second most common non-cardiac adverse effect of flecainide therapy:
In the FDA-approved labeling, visual disturbances occurred in 15.9% of patients with ventricular arrhythmias at any dose during clinical trials, with incidence increasing to 18% at the 400 mg/day dose 1
Multicenter studies report visual disturbances in approximately 28% of patients, often occurring in tandem with dizziness (30%), making these the two most frequently reported extracardiac adverse effects 2
Visual complaints include blurred vision, difficulty focusing, and spots before the eyes 1
Clinical Characteristics
The visual side effects of flecainide have several important features:
These symptoms typically appear early in therapy and tend to be intermittent, often decreasing over time with continued treatment 2
Visual disturbances are dose-related, with higher incidence at higher plasma levels (particularly when trough levels exceed 1 mcg/mL) 1
Less common but documented ocular effects include diplopia (double vision), eye pain or irritation, photophobia, and nystagmus, each occurring in less than 1% of patients 1
Management Approach
When visual disturbances occur on flecainide:
Most cases are mild and do not require discontinuation of therapy — only 10% of patients in short-term studies and 6% in long-term studies discontinued flecainide due to extracardiac adverse effects (including visual symptoms) 2
Dose reduction often resolves visual complaints, as these effects are generally related to the central nervous system and respond to dosage adjustment 3, 4
Monitor flecainide plasma levels, keeping trough concentrations below 0.7-1.0 mcg/mL to minimize adverse effects 5
Important Safety Context
While managing visual side effects, remember the critical cardiac contraindications:
Flecainide is absolutely contraindicated in patients with structural heart disease, ischemic heart disease, or reduced left ventricular ejection fraction due to increased risk of life-threatening ventricular arrhythmias 5
Regular ECG monitoring is essential, with QRS widening ≥25% from baseline requiring immediate dose reduction or discontinuation 6
Visual disturbances, while bothersome, are far less concerning than the cardiac risks in inappropriate patient populations 1