Complete adverse effect profile including incidence rates and management
Important Safety Information
This is not a complete list of all possible side effects. Contact your healthcare provider if you experience any unexpected symptoms. For serious or life-threatening side effects, seek emergency medical attention immediately.
Dizziness and lightheadedness
Visual disturbances (blurred vision, difficulty focusing, spots before the eyes)
Headache
Dyspnea (shortness of breath)
Palpitations
Fatigue and weakness (asthenia)
Nausea and abdominal discomfort
Tremor
Constipation
Proarrhythmia: worsening of existing arrhythmias or new ventricular tachycardia/fibrillation, including incessant or hard-to-resuscitate ventricular tachycardia
Increased mortality and nonfatal cardiac arrest in patients with prior myocardial infarction or structural heart disease (CAST trial)
Conversion of atrial flutter to 1:1 conduction with very rapid ventricular rate
New or worsened congestive heart failure due to negative inotropic effect
High-degree AV block, marked QRS prolongation, sinus node dysfunction
Unmasking of a Brugada-type ECG pattern
Hepatic dysfunction with elevated liver enzymes
Blood dyscrasias such as leukopenia, thrombocytopenia, or granulocytopenia
Peripheral neuropathy and paresthesias
Corneal deposits
Severe hypersensitivity or skin reactions
Seizures (most often in overdose)
Like all medications, Flecainide can cause side effects. However, not everyone who takes this medication will experience them. Many side effects are dose-dependent and may improve as your body adjusts to the medication. Others may require dose adjustment or medical attention.
Contact your healthcare provider promptly if you experience:
Seek immediate emergency medical care if you experience signs of: