Flecainide effects

Fleca.inide, Elecainide acetate, a fluorobenzamide, is a derivative of procainamide, and has been reported to be efficacious in suppressing both supraventricular and ventricular arrhythmias (26—29). The dmg is generally reserved for patients with serious and life-threatening ventricular arrhythmias. Elecainide depresses phase 0 depolarization of the action potential, slows conduction throughout the heart, and significantly prolongs repolarization (30). The latter effect indicates flecainide may possess some Class III antiarrhythmic-type properties (31). 

I c With only little effect on action potential duration Lorcainide, Flecainide, Propafenone... 

Class IC antiarrhythmic drugs such as flecainide or propafenone block the Na+ channel (open state propafenone open and inactivated state) with a very long dissociation time constant so that they alter normal action potential propagation. Flecainide increased mortality of patients recovering from myocardial infarction due to its proarrhythmic effects (CAST study). Action potential is shortened in Purkinje fibres but is prolonged in the ventricles. 

Ventricular fibrillation should be terminated by electrical defibrillation. Alternatively, lidocaine can be injected intravenously. In cases with lower frequency, ventricular tachyarrhythmia class I diugs such as aj marine, flecainide or propafenone are more effective as a result of the use-dependence of lidocaine. For prophylaxis treatment, amiodarone or sotalol may be helpful or the implantation of a cardioverter-defibrillator system. Acute amiodarone (i.v. in higher doses) can also terminate ventricular tachyarrhythmias. This action, however, seems to be mediated by its INa-blocking side effects and not (or less) by its class III like effects. 

Oral administration of bicarbonate may decrease the absorption of ketoconazole. Increased blood levels of quinidine, flecainide, or sympatiiomimetics may occur when these agents are administered with bicarbonate There is an increased risk of crystalluria when bicarbonate is administered with the fluoroquinolones. Fbssible decreased effects of lithium, methotrexate, chlorpropamide, salicylates, and tetracyclines may occur when these drag s are administered with sodium bicarbonate. Sodium bicarbonate is not administered within 2 hours of enteric-coated drugs the protective enteric coating may disintegrate before the drug reaches the intestine. 

Deneer VHM, Drese GB, Roemele PEH, Verhoef JC, Lie-A-Huen L, Kingma JH, Brouwers JRBJ, Junginger HE (2002) Buccal transport of flecainide and sotalol Effect of a bile salt and ionization state. Int J Pharm 241 127-134... 

Q79 As opposed to flecainide, amiodarone is not associated with pneumonitis as a side-effect. Signs of pneumonitis include progressive shortness of breath or cough. 

Clinical use of encainide is primarily associated with the presence of serious ventricular tachycardia however, like flecainide, it is also sufficiently effective for atrial arrhythmia and is used for natural occurrences. A synonym of this drug is enkaid. 

C (flecainide, encainide, propafenone) - Marked depression of phase 0. Slight effect on repolarization. Profound slowing of conduction. Encainide was voluntarily withdrawn from the market, but is still available on a limited basis. 

Ventricular proarrhythmic effects in patients with atrial fibrillation/flutter A review of the world literature revealed reports of 568 patients treated with oral flecainide for paroxysmal atrial fibrillation/flutter (PAF). Ventricular tachycardia was experienced in 0.4% of these patients. Of 19 patients in the literature with chronic atrial fibrillation (CAF), 10.5% experienced ventricular tachycardia (VT) or ventricular fibrillation (VF). Flecainide is not recommended for use in patients with CAF. Case reports of ventricular proarrhythmic effects in patients treated with flecainide for atrial... 

Not recommended in patients with less severe ventricular arrhythmias even if the patients are symptomatic. Because of proarrhythmic effects of flecainide, reserve use for patients in whom benefits outweigh risks. 

Once the arrhythmia is controlled, it may be possible to reduce the dose, as necessary, to minimize side effects or effects on conduction. PSVT and PAF The recommended starting dose is 50 mg every 12 hours. Doses may be increased in increments of 50 mg twice daily every 4 days until efficacy is achieved. For PAF patients, a substantial increase in efficacy without a substantial increase in discontinuation for adverse experiences may be achieved by increasing the flecainide dose from 50 to 100 mg twice/day. The maximum recommended dose for patients with paroxysmal supraventricular arrhythmias is 300 mg/day. 

Administration with amiodarone When flecainide is given in the presence of amiodarone, reduce the usual flecainide dose by 50% and monitor the patient closely for adverse effects. Plasma level monitoring is strongly recommended to guide dosage with such combination therapy. 

Pharmacology Flecainide has local anesthetic activity and belongs to the membrane stabilizing (Class I) group of antiarrhythmic agents it has electrophysiologic effects... 

Proarrhythmic effects Flecainide can cause new or worsened arrhythmias. Such proarrhythmic effects range from an increase in frequency of PVCs to the development of more severe ventricular tachycardia. 

Cardiac conduction Flecainide slows cardiac conduction in most patients to produce dose-related increases in PR, QRS, and QT intervals. The degree of lengthening of PR and QRS intervals does not predict either efficacy or the development of cardiac adverse effects. Patients may develop new first-degree AV heart block. Use caution and consider dose reductions. The JT interval (QT minus QRS) only widens approximately 4% on the average. Rare cases of torsade de pointes-type arrhythmias have occurred. 

Effects on pacemaker thresholds Flecainide increases endocardial pacing thresholds and may suppress ventricular escape rhythms. These effects are reversible. Use with caution in patients with permanent pacemakers or temporary... 

Drugs that may affect flecainide include amiodarone, cimetidine, cisapride, disopyramide, propranolol, ritonavir, urinary acidifiers/alkalinizers, and verapamil. Smoking may also have an effect. Drugs that may be affected by flecainide include cisapride, propranolol, and digoxin. 

WARNING Co administration w/ ritonavir assoc w/ Hep hepatic decomp w/ fatalities. D/C w/ S/Sxs of H Uses HIV 1 Infxn w/ highly Tx-experienced pts or HIV 1 strains resistant to multiple protease inhibitors. Must be used w/ ritonavir 200 mg Action Antiretroviral HIV-1 protease inhibitor Dose 500 mg PO bid w/ food, administer w/ ritonavir 200 mg PO bid Caution [C, -] Sulfa aU gy, Uvct Dz Contra Mod-severe hepatic insuff concomitant use w/ amiodarone, astemizole, bepridil, cisapride, ergots, flecainide, lovastatin, midazolam, pimozide, propafenone, quinidine, rifampin, simvastatin, terfenadine, triazolam, St. John s wort Disp Caps SE HA, GI distress, rash, fati e, fat redistribution, hyperglycemia, Hep, liver Dz, lipid elevations Interactions T Effects OF anticoagulants, antipits, azole antifun-... 

CAST (1989) Preliminary report effect of encainide and flecainide on mortality in a randomized trial of arrhythmia suppression after myocardial infarction. The cardiac arrhythmia suppression trial (CAST) investigators. The New En and Journal of Medicine, 321, 406 12. 

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