Propafenone Hydrochloride

Indications

Propafenone Hydrochloride is used for: Supraventricular and ventricular arrhythmias, Atrial Fibrillation/Flutter

Adult Dose

Oral Supraventricular and ventricular arrhythmias, Atrial Fibrillation/Flutter Adult: For immediate-release tablet: Usual initial doses: 150 mg tid, may increase at intervals of 3-4 days up to 300 mg tid. Dose reduction is recommended in patients weighing <70 kg. Elderly: Dose reduction is recommended. Hepatic impairment: Dose reduction is recommended.

Child Dose

Safety and efficacy not established

Renal Dose

Administration

Should be taken with food. Take after meals. Swallow whole, do not chew/crush.

Contra Indications

Uncontrolled heart failure, marked hypotension, severe bradycardia and heart block, conduction abnormalities, cardiogenic shock, myasthenia gravis.

Precautions

Severe pulmonary obstructive diseases, CHF, cardiac pacemaker, impaired renal/hepatic function, pregnancy, lactation, elderly. Correct electrolyte disturbances before starting treatment. May worsen heart failure in patients with preexisting organic heart disease. May worsen or cause new severe ventricular arrhythmias e.g. ventricular tachycardia or fibrillation. May aggravate electrically induced ventricular tachycardia in some patients. Lactation: Crosses into breast milk; discontinue drug or do not nurse

Pregnancy-Lactation

Interactions

Effect may be potentiated by local anesth, beta-blockers, TCA. May increase plasma level of propranolol, metoprolol, desipramine, cyclosporin, digoxin, theophylline. Plasma conc may rise when taken simultaneously w/ cimetidine or quinidine. May enhance effect of anticoagulant. Simultaneous administration w/ phenobarb or rifamycin may decrease propafenone plasma conc, possibly in sub-therapeutic levels.

Adverse Effects

Side effects of Propafenone Hydrochloride : >10% Unusual taste (7-23%),Dizziness/lightheadedness (7-15%),N/V (3-11%) 1-10% Constipation (4-8%),Headache (2-6%),Intraventricular conduction delay (4%),Fatigue (6%),Blurred vision (3%),Weakness (3%),Dyspnea (2%),Wild complex tachycardia (2%),Bradycardia (2%),Palpitations (2%),Tremor (2%),Anorexia (2%),Diarrhea (2%),Ataxia (2%),1°AV block (2-5%),Angina (5%),Palpitations (3%),CHF (2-3% ),Chest pain (2%),Bradyarrhythmia (2%),AF (1%),Bundle branch block (1%),2nd degree AV block (1%),Hypotension (1%),Sinus arrest (1%) Frequency Not Defined Lethargy,Rash,Dyspepsia,Dry mouth,Agranulocytosis,Hepatotoxicity (rare),Systemic lupus erythematosus (rare),Bronchospasm (rare) Potentially Fatal: SA/AV or intraventricular blocks. Severe hypotension, especially in elderly.

Mechanism of Action

Propafenone is a class 1C antiarrhythmic drug with local anaesthetic effects, and a direct stabilising action on myocardial membranes. The electrophysiological effect manifests itself in a reduction of upstroke velocity (Phase 0) of the monophasic action potential. In Purkinje fibers, and to a lesser extent myocardial fibers, propafenone reduces the fast inward current carried by sodium ions. Diastolic excitability threshold is increased and effective refractory period prolonged. Propafenone reduces spontaneous automaticity and depresses triggered activity.