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Pharmacologic class: Cardiac benzamide local anesthetic
Therapeutic class: Antiarrhythmic (class IC)
Pregnancy risk category C
Inhibits fast sodium channels of myocardial cell membrane. Also slows conduction, shortens action potential, stops paroxysmal reentrant supraventricular tachycardia, and decreases conduction in accessory pathways in Wolff-Parkinson-White syndrome.
Tablets: 50 mg, 100 mg, 150 mg
Indications and dosages
➣ Supraventricular tachyarrhythmias (including paroxysmal supraventricular tachycardia and paroxysmal atrial fibrillation or flutter)
Adults: Initially, 50 mg P.O. q 12 hours, increased by 50 mg b.i.d. q 4 days until desired response occurs or maximum daily dosage of 300 mg is reached
➣ Sustained, life-threatening ventricular tachycardia
Adults: Initially, 100 mg P.O. q 12 hours, increased by 50 mg b.i.d. q 4 days until desired response occurs or maximum daily dosage of 400 mg is reached
• Heart failure
• Renal impairment
• Ventricular arrhythmias
• Wolff-Parkinson-White syndrome
• Hypersensitivity to drug
• Preexisting atrioventricular block or right bundle-branch block
• Recent MI
• Cardiogenic shock
Use cautiously in:
• heart failure, renal impairment
• patients taking concurrent amiodarone, beta-adrenergic blockers, disopyramide, or verapamil
• pregnant or breastfeeding patients
• children (safety not established).
• Initiate therapy only in hospital setting with trained personnel and continuous ECG monitoring.
• Before giving, correct hypokalemia or hyperkalemia.
• Be aware that dosage may be reduced once arrhythmias have been adequately controlled.
CNS: dizziness, anxiety, fatigue, headache, depression, malaise, tremor, weakness, hypoesthesia, paresthesia
CV: chest pain, palpitations, second- or third-degree heart block, heart failure, new or worsening arrhythmias
EENT: blurred vision, visual disturbances, corneal deposits
GI: nausea, vomiting, constipation, abdominal pain, dyspepsia, anorexia
Skin: rash, diaphoresis
Other: edema, fever
Drug-drug. Acidifying drugs: increased renal elimination, decreased efficacy of flecainide (with urine pH below 5)
Alkalizing drugs: increased flecainide blood level, possible toxicity
Amiodarone: doubling of flecainide blood level
Beta-adrenergic blockers: increased blood levels of both drugs
Beta-adrenergic blockers, disopyramide, verapamil: additive myocardial depressant effect
Digoxin: 15% to 25% increase in digoxin blood level
Other antiarrhythmics (including calcium channel blockers): increased risk of arrhythmias
Drug-diagnostic tests. Alkaline phosphatase: increased level (with prolonged therapy)
Drug-food. Foods that decrease urine pH below 5 (such as acidic juices): increased renal elimination and possibly decreased efficacy of drug
Foods that increase urine рH above 7 (as in strict vegetarian diets): increased drug blood level
Drug-behaviors. Smoking: increased plasma clearance and decreased efficacy of drug
☞ Monitor ECG for worsening arrhythmias.
• Measure pacing threshold 1 week before therapy starts and again after 1 week of therapy.
• Monitor potassium and flecainide blood levels.
• Assess respiratory status regularly.
• Monitor hepatic function tests.
☞ Instruct patient to immediately report cardiac or respiratory symptoms, unusual tiredness, or yellowing of skin or eyes.
• Tell patient drug may cause numbness. Advise him to avoid injury to areas with sensory impairment.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, alertness, and vision.
• Advise patient to minimize GI upset by eating small, frequent servings of food and drinking adequate fluids.
• Tell female patient to inform prescriber if she is pregnant or breastfeeding.
• Inform patient that he'll undergo regular blood testing during therapy.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and behaviors mentioned above.