BLACK BOX WARNING
- ventricular proarrhythmia
propafenone
Brand: Rythmol
⚠ BBW Prototype: flecainide
Drug Class: antiarrhythmic (Class IC)
Drug Family: antiarrhythmic
Subclass: sodium channel blocker + weak beta-blocker
Organ Systems: cardiovascular
Mechanism of Action
Sodium channel blocker with additional weak beta-blocking and calcium channel blocking properties; slows conduction velocity.
fast sodium channelsbeta-1 adrenergic receptor (weak)
Indications
- paroxysmal AF/SVT in structurally normal hearts
- ventricular arrhythmias
Contraindications
- structural heart disease
- cardiogenic shock
- severe bronchospasm (weak beta-block)
- uncontrolled HF
Adverse Effects
Common
- dizziness
- metallic taste
- nausea
- bradycardia
Serious
- proarrhythmia
- worsening HF
- 1:1 flutter
Pharmacokinetics (ADME)
| Absorption | 5-50% oral (extensive first-pass; CYP2D6 polymorphism dependent) |
| Distribution | moderate |
| Metabolism | extensive hepatic CYP2D6, CYP3A4 |
| Excretion | renal (<1% unchanged) |
| Half-life | 2-10 hours |
| Onset | 2-3 hours |
| Peak | 3.5 hours |
| Duration | 8-12 hours |
| Protein Binding | 97% |
| Vd | 3.6 L/kg |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| CYP2D6 inhibitors | dramatically increased propafenone levels in extensive metabolizers | major |
| warfarin | increases warfarin levels — monitor INR | major |
| digoxin | increases digoxin concentrations | moderate |
Nursing Considerations
- Pill-in-pocket approach same as flecainide
- Metallic taste is common adverse effect
- Weak beta-blockade — may cause bronchospasm
- CYP2D6 poor metabolizers have 5-10x higher exposure
Clinical Pearls
- Unique metallic taste adverse effect due to local anesthetic properties
- Propafenone pill-in-pocket for AF cardioversion
Safety Profile
Pregnancy avoid
Lactation avoid
Renal Adjustment Required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.