Propafenone arrhythmia with

PROPAFENONE ANTIVIRALS-PROTEASE INHIBITORS Amprenavir, ritonavir and possibly saquinavir and tipranavir with ritonavir t propafenone levels, with risk of ventricular arrhythmias Uncertain Manufacturers recommend avoiding co-administration of propafenone and amprenavir, ritonavir or tipranavir... 

Because of the proarrhythmic effects of propafenone, reserve its use for patients in whom the benefits of treatment outweigh the risks. The use of propafenone is not recommended in patients with less severe ventricular arrhythmias, even if the patients are symptomatic. 

Proarrhythmic effects Propafenone may cause new or worsened arrhythmias. Such proarrhythmic effects range from an increase in frequency of PVCs to the development of more severe ventricular tachycardia, ventricular fibrillation or torsade de pointes, which may lead to fatal consequences. It is essential that each patient be evaluated electrocardiographically and clinically prior to, and during therapy to determine whether response to propafenone supports continued use. Non-life-threatening arrhythmias Use of propafenone is not recommended in patients with less severe ventricular arrhythmias, even if the patients are symptomatic. 

As propafenone exerts both beta blockade and a (dose-related) negative inotropic effect on cardiac muscle, fully compensate patients with CHF before receiving propafenone. If CHF worsens, discontinue propafenone unless CHF is due to the cardiac arrhythmia and, if indicated, restart at a lower dosage only after adequate cardiac compensation has been established. 

Approved indications for propafenone include treatment of supraventricular arrhythmias and life-threatening ventricular arrhythmias in the absence of structural heart disease. Propafenone has been shown to increase mortality in patients with structural heart disease, and so extreme caution must be used in this subset of patients. As with flecainide, the patient should be hospitalized for initiation of therapy. 

Propafenone has some structural similarities to propranolol and possesses weak 3-blocking activity. Its spectrum of action is very similar to that of quinidine, but it does not prolong the action potential. Its sodium channel-blocking kinetics are similar to that of flecainide. Propafenone is metabolized in the liver, with an average half-life of 5-7 hours. The usual daily dosage of propafenone is 450-900 mg in three divided doses. The drug is used primarily for supraventricular arrhythmias. The most common adverse effects are a metallic taste and constipation arrhythmia exacerbation can also occur. 

PROPAFENONE I. ANTIARRHYTHMICS - disopyra-mide, procainamide 2. ANTIBIOTICS - macrolides (especially azithromycin, clarithromycin, parenteral erythromycin, telithromycin), quinolones (especially moxifloxacin), quinupristin/ dalfopristin 3. ANTICANCER AND IMMUNOMODULATING DRUGS -arsenic trioxide 4. ANTIDEPRESSANTS - TCAs, venlafaxine 5. ANTIEMETICS-dolasetron 6. ANTIFUNGALS-fluconazole, posaconazole, voriconazole 7. ANTIHISTAMINES - terfenadine, hydroxyzine, mizolastine 8. ANTI-M ALARIALS - artemether with lumefantrine, chloroquine, hydroxychloroquine, mefloquine, quinine 9. ANTIPROTOZOALS - pentamidine isetionate 10. ANTIPSYCHOTICS-atypicals, phenothiazines, pimozide II. BETA-BLOCKERS - sotalol 12. BRONCHODILATORS -parenteral bronchodilators 13. CNS STIMULANTS - atomoxetine Risk of ventricular arrhythmias, particularly torsades de pointes Additive effect these drugs prolong the Q-T interval. Also, amitriptyline, clomipramine and desipramine levels may be t by propafenone. Amitriptyline and clomipramine may t propafenone levels. Propafenone and these TCAs inhibit CYP2D6-mediated metabolism of each other Avoid co-administration... 

Ravid S, Podrid PJ, Novrit B. Safety of long-term propafenone therapy for cardiac arrhythmia—experience with 774 patients. J Electrophysiol 1987 1 580-90. 

Class 1C drugs (flecainide, moricizine, propafenone) block sodium channels but do not affect potassium current. Therefore, they do not prolong the ventricular action potential or increase the QT interval. However, this class of drugs is quite proarrhythmic, and its use should be reserved for patients who have arrhythmias refractory to other treatments. Additionally, these drugs should not be used in patients with underlying heart disease. 

Alternatives to amiodarone include the type Ic drugs (e.g., fle-cainide and propafenone) and the type III blockers (e.g., sotalol and dofetilide). Because of the risk of pro arrhythmia, the type Ic drugs should be reserved for those without heart disease (i.e., lone atrial fibrillation). Sotalol has been shown to be at least as effective as quinidine in preventing recurrences of atrial fibrillation." However, treatment with either quinidine or sotalol is associated with a similar incidence of torsade de pointes. Since this form of proarrhythmia occurs primarily with higher doses of sotalol (quinidine usually causes torsade de pointes at low or therapeutic concentrations), it may be predicted more easily and therefore avoided. Nonetheless, it is possible that sotalol increases mortality in patients with atrial fibrillation similar to quinidine, and this requires further study." ... 

Moricizine (600 to 900 mg/day given every 8 hours in three equally divided doses) is indicated in the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia, that are life threatening. Because of the proarrhythmic effects of moricizine, its use should be reserved for patients in whom the benefits of treatment outweigh the risks. Moricizine is a class 1C antiarrhythmic agent with potent local anesthetic activity and myocardial-membrane-stabilizing effects. It shares some of the characteristics of the class lA (disopyramide, procainamide, or quinidine), of class IB (lidocaine, mexiletene, phenytoin, or tocainide), or class 1C agents (encainide, flecainide, or propafenone) in that it reduces the fast inward current carried by sodium ions. Moricizine shortens phase 2 and 3... 

Ibutilide, a class in antiarrhythmic, is known to increase the QT interval, so increasing the risk of torsade de pointes arrhythmia. Class Ic antiarrhythmics such as propafenone and flecainide generally shorten the QT interval. It is possible that class Ic antiarrhythmics may usefully attenuate the risk of torsade de pointes with ibutilide, and ibutilide may be... 

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