Before taking flecainide, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, liver problems, other heart problems (such as previous heart attack, heart pacemaker).
This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.
Flecainide may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can infrequently result in serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.
The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using flecainide, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).
Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/”water pills”) or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using flecainide safely.
Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above).
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
This medication passes into breast milk. However, this drug is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.
Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.
Many drugs besides flecainide may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, pimozide, procainamide, quinidine, sotalol, and macrolide antibiotics (such as erythromycin), among others. (See also Precautions section.)
Other medications can affect the removal of flecainide from your body, which may affect how flecainide works. Examples include cimetidine, fluconazole, certain HIV protease inhibitors (such as ritonavir, tipranavir), anti-seizure drugs (such as carbamazepine, phenytoin, phenobarbital), among others.
This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.