Propafenone

Administration

• Type:Antiarrhythmics
• Dosage Forms: Oral cap, Oral tablet
• Routes of Administration: PO
• Common Trade Names: Rhythmol

Adult Dosing

Sustained Ventricular Tachycardia

• 150 mg PO q 8 hrs
• Dosage may be increased at 3-4 days to 225 mg PO q 8 hrs
• Max dosage: 300 mg PO q 8 hrs

New Onset Atrial fibrillation

• 450 to 600 mg PO as a single dose

Sinus Rhythm Maintenance in Atrial fibrillation or Atrial flutter

• See sustained VT dosing

PSVT Prophylaxis in AVRT including WPW

• 300 mg q 8 hrs for 48 hrs (max 900 mg q 8 hrs)
• Limited data regarding dosing

Pediatric Dosing

PSVT Prophylaxis in AVRT including WPW

• 8 to 10 mg/kg/day PO in 3 divided doses.
• Increase by 2 to 3 mg/kg/day every 2 to 3 days
• Max 15 mg/kg/day PO in 3 divided doses.

Special Populations

Pregnancy Rating

• No assigned FDA category
• No associated risk of miscarriage, birth defects, or adverse maternal or fetal outcomes with this drug

Lactation risk

• Dosages up to 900mg/day not expected to cause adverse effects in breast fed infants

Renal Dosing

• Adult: No dosage adjustment needed
• Pediatric: No dosage adjustment needed

Hepatic Dosing

• Adult: Administer 20-30% of normal IR dose and monitor closely; consider dose reduction if administering ER dose
• Pediatric: No specified guidelines

Contraindications

• Allergy to class/drug
• Significant QRS widening
• High Grade Heart Block
• Heart Failure
• Left Ventricular Dysfunction
• Bradycardia
• Cardiogenic Shock
• Electrolyte Imbalance
• Hypotension
• Sick Sinus Syndrome
• Long QT Syndrome
• Brugada Syndrome
• Renal failure (relative)
• Hepatic failure (relative)
• Asthma
• COPD
• Bronchospasm
• SLE

Adverse Reactions

Serious

• Cardiac arrhythmia (2%-10%; new or worsened)
• Cardiac failure (1%-4%)

Common

• Unusual Taste (3%-23%)
• Dizziness (4%-15%)
• Nausea/Vomiting (<11%)

Pharmacology

• Half-life: Extensive metabolizers: 2-10 hours; Poor metabolizers: 10-32 hours
• Metabolism: Hepatic via CYP2D6, CYP3A4 and CYP1A2
• Excretion: Urine (<1% unchanged; remainder as glucuronide or sulfate conjugates); feces

Mechanism of Action

• Class 1c antiarrhythmic agent w/ local anesthetic properties
• Blocks the fast inward sodium current, slowing the rate of increase of the action potential.
• Prolongs conduction/refractoriness in myocardium, reduces spontaneous automaticity, and exhibits some beta-blockade activity