Flecainide Acetate

Pronunciation

Pronunciation: fleh-CANE-ide ASS-uh-TATE
Class: Antiarrhythmic

Trade Names

Tambocor
- Tablets 50 mg
- Tablets 100 mg
- Tablets 150 mg

Apo-Flecainide (Canada)

Pharmacology

Produces a dose-related decrease in intracardiac conduction in all parts of the heart; also has local anesthetic activity.

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Pharmacokinetics

Absorption

About 100% absorbed. T max is 1 to 6 h.

Distribution

About 40% protein bound.

Metabolism

There are 2 major metabolites: meta-o-dealkylated flecainide (active, but about 1/ 5 as potent) and meta-o-dealkylated lactam of flecainide (nonactive).

Elimination

The t ½ is 12 to 27 h; 10% to 50% is excreted in the urine as unchanged drug.

Hemodialysis

About 1% of unchanged drug is removed by hemodialysis.

Special Populations

Renal Function Impairment

The t ½ is prolonged.

Children
At birth

The t ½ is up to 29 h.

At 3 mo of age

The t ½ is 11 to 12 h.

At 1 to 12 yr of age

The t ½ is 6 to 8 h.

CHF (NYHA Class III)

The t ½ is increased.

Indications and Usage

Prevention of paroxysmal atrial fibrillation/flutter (PAF) associated with disabling symptoms; paroxysmal supraventricular tachycardias (PSVTs), including AV nodal reentrant tachycardia and AV reentrant tachycardia; prevention of documented life-threatening ventricular arrhythmias, such as sustained ventricular tachycardia (VT).

Contraindications

Preexisting second- or third-degree AV block; right bundle branch block when associated with a left hemiblock (unless a pacemaker is present); presence of cardiogenic shock; hypersensitivity to the drug.

Dosage and Administration

PSVT, PAF
Adults Initial dose

PO 50 mg every 12 h, increasing 50 mg twice daily every 4 days until efficacy is achieved. Max, 300 mg/day.

Sustained VT
Adults Initial dose

PO 100 mg every 12 h, increasing 50 mg twice daily every 4 days until efficacy is achieved. Max, 400 mg/day.

Children
Younger than 6 mo of age

PO 50 mg/m 2 divided into 2 or 3 equally spaced doses.

Older than 6 mo of age

PO 100 mg/m 2 /day. The maximum recommended dose is 200 mg/m 2 /day.

Renal Function Impairment

When CrCl is less than 35 mL/min, the initial dose is 100 mg once daily (or 50 mg twice daily).

Administration with Amiodarone

Reduce dose of flecainide 50% when given with amiodarone.

Drug Interactions

Amiodarone

Increased flecainide plasma levels; reduce dose of flecainide 50%.

Cimetidine

Increased bioavailability and half-life of flecainide.

Cisapride, disopyramide, verapamil

Has negative inotropic effects; administer with flecainide only if benefit outweighs the risks. Coadministration with flecainide is not recommended because of the increased risk of life-threatening cardiac arrhythmias.

Digoxin

Increased digoxin plasma levels.

Drugs that inhibit CYP2D6 (eg, quinidine, ritonavir)

Flecainide plasma concentrations may be elevated, increasing the risk of toxicity.

Propranolol

Levels of either drug may be increased; additive negative inotropic effects.

Smoking

Increased dosage may be required.

Urinary acidifiers

Effects of flecainide may be decreased.

Urinary alkalinizers

Effects of flecainide may be increased.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Palpitation (6%); chest pain (5%); tachycardia (1% to less than 3%); sinus bradycardia, sinus pause, sinus arrest (1%); new or worsening arrhythmia, unresuscitatable VT or ventricular fibrillation, new or worsening CHF, second- or third-degree AV block.

CNS

Dizziness including lightheadedness, faintness, unsteadiness, and near syncope (19%); headache (10%); fatigue (8%); asthenia, tremor (5%); hypoesthesia, paresthesia, paresis, ataxia, flushing, increased sweating, vertigo, syncope, somnolence, anxiety, insomnia, depression, malaise (1% to less than 3%).

Dermatologic

Rash (1% to less than 3%).

EENT

Visual disturbances including blurred vision, difficulty focusing, spots before eyes (16%); tinnitus, diplopia (1% to less than 3%).

GI

Nausea (9%); constipation (4%); abdominal pain (3%); vomiting, diarrhea, dyspepsia, anorexia (1% to less than 3%).

Respiratory

Dyspnea (10%).

Miscellaneous

Edema (4%); fever (1% to less than 3%).

Precautions

Warnings

Mortality

An excessive mortality or nonfatal cardiac arrest rate was observed in patients with nonlife-threatening ventricular arrhythmias who had a recent MI.

Ventricular pro-arrhythmic effects have been observed in patients with atrial fibrillation/flutter. This drug is not recommended in patients with chronic atrial fibrillation.


Pregnancy

Category C .

Lactation

Excreted in breast milk.

Children

Safety and efficacy not established.

Hepatic Function

Do not use in patients with hepatic function impairment unless benefits outweigh risks.

CV disorders

Use with caution in patients with arrhythmias, CHF, cardiomyopathy, low ejection fraction, and conduction abnormalities. Use with extreme caution in patients with sick sinus syndrome, because drug may cause sinus bradycardia, sinus pause, or sinus arrest.

Conduction disturbance

Flecainide slows cardiac conduction in most patients to produce a dose-related increase in PR, QRS, and QT intervals.

Pacemaker threshold

Flecainide increases endocardial pacing thresholds and may suppress ventricular escape rhythms in patients with pacemakers.

Potassium imbalances

Effect of flecainide may be altered in patients with hypokalemia or hyperkalemia; correct condition before administering flecainide.

Overdosage

Symptoms

Nausea and vomiting, convulsions, hypotension, bradycardia, syncope, extreme widening of the QRS complex, widening of the QT interval, widening of the PR interval, VT, AV nodal block, asystole, bundle branch block, cardiac failure, cardiac arrest, death.

Patient Information

  • Advise patient that dose of medication will be changed periodically to obtain max benefit.
  • Caution patient to take prescribed dose every 8 or 12 h exactly as ordered. Advise patient that serious heart disturbances can result from missing doses.
  • Advise patient to take each dose without regard to meals but to take with food if stomach upset occurs.
  • Caution patient not to change the dose or stop taking unless advised by health care provider. Advise patient that serious adverse reactions can result from increasing or decreasing the dose without medical supervision.
  • Inform patient that drug controls, but does not cure, abnormal heart rhythm and to continue taking as prescribed once heart rhythm has been controlled.
  • Instruct patient to continue taking other heart medications as prescribed by health care provider.
  • Instruct patient in BP and pulse measurement skills.
  • Advise patient to monitor and record BP and pulse at home and to inform health care provider if abnormal measurements are noted. Also advise patient to take record of BP and pulse to each follow-up visit.
  • Advise patient with heart failure, or those taking other medications with negative inotropic effect, to monitor and record weight on a daily basis and inform health care provider if noting unexplained or rapid weight gain.
  • Instruct patient to lie or sit down if experiencing dizziness or lightheadedness when standing.
  • Advise patient to notify health care provider if any of the following occur: frequent episodes of dizziness or lightheadedness, persistent fatigue, persistent headache, nausea, any other unusual or unexplained symptom or sign.
  • Instruct patient to immediately report fainting, pounding in chest, new or worsening shortness of breath, change in pulse or heart rhythm, swelling in feet or ankles, or rapid weight gain to health care provider.
  • Caution patient that drug may cause dizziness or drowsiness and to use caution while driving or performing other tasks requiring mental alertness or coordination until tolerance is determined.
  • Advise patient to carry medical identification (eg, card, bracelet) describing cardiac condition and medication regimen.
  • Offer family instruction in basic life support.

Copyright © 2009 Wolters Kluwer Health.

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