Most commonly giddiness, dizziness and lightheadedness.
Visual disturbances, such as double vision and blurring of vision, may occur. More rarely nausea and vomiting have been reported. These effects are usually transient and disappear upon continuing or reducing the dosage.
Pro-arrhythmic effects have been reported in a small number of patients.
A few cases of elevated liver enzymes and jaundice have been reported which were possibly related to treatment with Flecainide acetate (Tambocor).
During long term therapy a few cases of peripheral neuropathy, parathesia and ataxia have been reported.
Extremely rare cases of corneal deposits, pulmonary fibrosis, interstitial lung disease and pneumonitis have also been reported.