Flecainide acetate
Flecainide acetate (Tambocor)
Flecainide acetate
(fleh- KAY-nyd)
Pregnancy Category: C Tambocor (Rx)

Classification: Antiarrhythmic, class IC

See Also: See also Antiarrhythmic Agents .

Action/Kinetics: The antiarrhythmic effect is due to a local anesthetic action, especially on the His-Purkinje system in the ventricle. Drug decreases single and multiple PVCs and reduces the incidence of ventricular tachycardia. Peak plasma levels: 3 hr.; steady state levels: 3-5 days. Effective plasma levels: 0.2-1 mcg/mL (trough levels). t 1/2: 20 hr (12-27 hr). Forty percent is bound to plasma protein. Approximately 30% is excreted in urine unchanged. Impaired renal function decreases rate of elimination of unchanged drug. Food or antacids do not affect absorption.

Uses: Life-threatening arrhythmias manifested as sustained ventricular tachycardia. Prevention of paroxysmal supraventricular tachycardias (PSVT) and paroxysmal atrial fibrillation or flutter (PAF) associated with disabling symptoms but not structural heart disease. Antiarrhythmic drugs have not been shown to improve survival in clients with ventricular arrhythmias.

Contraindications: Cardiogenic shock, preexisting second- or third-degree AV block, right bundle branch block when associated with bifascicular block (unless pacemaker is present to maintain cardiac rhythm). Recent MI. Cardiogenic shock. Chronic atrial fibrillation. Frequent premature ventricular complexes and symptomatic nonsustained ventricular arrhythmias. Lactation.

Special Concerns: Use with caution in sick sinus syndrome, in clients with a history of CHF or MI, in disturbances of potassium levels, in clients with permanent pacemakers or temporary pacing electrodes, renal and liver impairment. Safety and efficacy in children less than 18 years of age are not established. The incidence of proarrhythmic effects may be increased in geriatric clients.

Side Effects: CV: New or worsened ventricular arrhythmias, increased risk of death in clients with non-life-threatening cardiac arrhythmias new or worsened CHF, palpitations, chest pain, sinus bradycardia, sinus pause, sinus arrest, ventricular fibrillation, ventricular tachycardia that cannot be resuscitated second- or third-degree AV block, tachycardia, hypertension, hypotension, bradycardia, angina pectoris. CNS: Dizziness, faintness, syncope, lightheadedness, neuropathy, unsteadiness, headache, fatigue, paresthesia, paresis, hypoesthesia, insomnia, anxiety, malaise, vertigo, depression, seizures euphoria, confusion, depersonalization, apathy, morbid dreams, speech disorders, stupor, amnesia, weakness, somnolence. GI: Nausea, constipation, abdominal pain, vomiting, anorexia, dyspepsia, dry mouth, diarrhea, flatulence, change in taste. Ophthalmic: Blurred vision, difficulty in focusing, spots before eyes, diplopia, photophobia, eye pain, nystagmus, eye irritation, photophobia. Hematologic: Leukopenia, thrombocytopenia. GU: Decreased libido, impotence, urinary retention, polyuria. Musculoskeletal: Asthenia, tremor, ataxia, arthralgia, myalgia. Dermatologic: Skin rashes, urticaria, exfoliative dermatitis, pruritus, alopecia. Other: Edema, dyspnea, fever, bronchospasm flushing, sweating, tinnitus, swollen mouth, lips, and tongue.

Overdose Management: Symptoms: Lengthening of PR interval; increase in QRS duration, QT interval, and amplitude of T wave; decrease in HR and contractility; conduction disturbances; hypotension; respiratory failure or asystole. Treatment: Charcoal will remove unabsorbed drug up to 90 min after drug ingestion. Administration of dopamine, dobutamine, or isoproterenol. Artificial respiration. Intra-aortic balloon pumping, transvenous pacing (to correct conduction block). Acidification of the urine may be beneficial, especially in those with an alkaline urine. Due to the long duration of action of the drug, treatment measures may have to be continued for a prolonged period of time.

Drug Interactions: Acidifying agents / Renal excretion of flecainide Alkalinizing agents / Renal excretion of flecainide Amiodarone / Plasma levels of flecainide Cimetidine / Bioavailability and renal excretion of flecainide Digoxin / Digoxin plasma levels Disopyramide / Additive negative inotropic effects Propranolol / Additive negative inotropic effects; also, plasma levels of both drugs Smoking (Tobacco) / Plasma clearance of flecainide Verapamil / Additive negative inotropic effects

How Supplied: Tablet: 50 mg, 100 mg, 150 mg

Dosage
?Tablets Sustained ventricular tachycardia.
Initial: 100 mg q 12 hr; then, increase by 50 mg b.i.d. q 4 days until effective dose reached. Usual effective dose: 150 mg q 12 hr, not to exceed 400 mg/day.
PSVT, PAF.
Initial: 50 mg q 12 hr; then, dose may be increased in increments of 50 mg b.i.d. q 4 days until effective dose reached. Maximum recommended dose: 300 mg/day. NOTE: For PAF clients, increasing the dose from 50 to 100 mg b.i.d. may increase efficacy without a significant increase in side effects.
NOTE: For clients with a C _CR less than 35 mL/min/1.73 m ², the starting dose is 100 mg once daily (or 50 mg b.i.d.). For less severe renal disease, the initial dose may be 100 mg q 12 hr.