PROPAFENONE

PROPAFeNONE (pro-pa'fen-one) Rythmol Classifications: antiarrhythmic class ic; Therapeutic: antiarrhythmic class ic Prototype: Flecainide Pregnancy Category: C

Availability

150 mg, 225 mg, 300 mg tablets

Action

Class IC antiarrhythmic drug with a direct stabilizing action on myocardial membranes. Reduces spontaneous automaticity. Exerts a negative inotropic effect on the myocardium.

Therapeutic Effect

Appropriate dose and concentration decreases rate of single and multiple PVCs; additionally, it suppresses ventricular arrhythmias.

Uses

Ventricular arrhythmias.

Unlabeled Uses

Atrial tachyarrhythmias, reentrant arrhythmias, Wolff-Parkinson-White syndrome.

Contraindications

Uncontrolled CHF, cardiogenic shock, sinoatrial, AV or intraventricular disorders (e.g., sick sinus node syndrome, AV block) without a pacemaker; cardiogenic shock; bradycardia, QT prolongation; marked hypotension; bronchospastic disorders; electrolyte imbalances; hypersensitivity to propafenone; nonlife-threatening arrhythmias; chronic bronchitis, emphysema; pregnancy (category C). Safety and efficacy in children are not established.

Cautious Use

CHF, AV block; hepatic/renal impairment; older adult patients; lactation.

Route & Dosage

Ventricular Arrhythmias Adult: PO Initiate with 150 mg q8h, may be increased at 3–4 d intervals (max: 300 mg q8h)

Administration

• Dosage increments gradually are usually made with older adults or those with previous extensive myocardial damage.
• Significant dose reduction is warranted with severe liver dysfunction. Consult physician.
• Store at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

CNS: Blurred vision, dizziness, paresthesias, fatigue, somnolence, vertigo, headache. CV: Arrhythmias, ventricular tachycardia, hypotension, bundle branch block, AV block, complete heart block, sinus arrest, CHF. Hematologic: Leukopenia, granulocytopenia (both rare). GI: Nausea, abdominal discomfort, constipation, vomiting, dry mouth, taste alterations, cholestatic hepatitis. Skin: Rash.

Interactions

Drug: Amiodarone, quinidine increases the levels and toxicity of propafenone. May increase levels and toxicity of tricyclic antidepressants, cyclosporine, digoxin, beta blockers, theophylline, and warfarin may increase levels of both propafenone and diltiazem. Phenobarbital decreases levels of propafenone.

Pharmacokinetics

Absorption: Readily from GI tract. Peak: 3.5 h. Distribution: 97% protein bound, highest concentrations in the lung. Crosses placenta, distributed into breast milk. Metabolism: Extensively metabolized in the liver. Elimination: 18.5–38% of dose excreted in urine as metabolites. Half-Life: 5–8 h.

Nursing Implications

Assessment & Drug Effects

• Monitor cardiovascular status frequently (e.g., ECG, Holter monitor) to determine effectiveness of drug and development of new or worsened arrhythmias.
• Monitor patients with preexisting CHF closely for worsening of this condition. Monitor for digoxin toxicity with concurrent use, because drug may increase serum digoxin levels.
• Report development of second- or third-degree AV block or significant widening of the QRS complex. Dosage adjustment may be warranted.

Patient & Family Education

• Report to physician any of following: Chest pain, palpitations, blurred or abnormal vision, dyspnea, or signs and symptoms of infection.
• Be aware when taking concurrent warfarin of possible increase in plasma levels that increase bleeding risk. Report unusual bleeding or bruising.
• Monitor radial pulse daily and report decreased heart rate or development of an abnormal heartbeat.
• Be aware of possibility of dizziness and need for caution with walking, especially in older adult or debilitated patients.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug