Propafenone
RYTHMOL
Pronunciation: proe-pa-FEEN-oen (RITH-mawl)
“Proper fin Rhythm y’all”
What it isClass IC sodium channel blocker with weak beta blockade; atrial fibrillation in structurally normal hearts.
Why this oneIt works as a pill-in-the-pocket strategy and its beta blockade gives some rate control that flecainide lacks.
What limits itContraindicated in structural or ischemic heart disease after CAST. Pair with an AV nodal blocker; a metallic taste is characteristic.
FDA-approved for
- arrhythmias (1989)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Paroxysmal AF/PSVT (delay recurrence, no structural heart disease); life-threatening ventricular arrhythmias | Adults | 150 mg every 8 h (450 mg/day) | 225 mg every 8 h (675 mg/day) | 300 mg every 8 h (900 mg/day) |
Titration Increase at minimum 3–4 day intervals.
Renal ~50% of metabolites renally excreted; monitor for signs of overdosage in renal impairment.
Hepatic Bioavailability increases (~70% in severe dysfunction); consider dose reduction and monitor.
Instructions
- Consider dose reduction with hepatic impairment, marked QRS widening, or 2nd/3rd-degree AV block
- Avoid simultaneous use of a CYP2D6 inhibitor plus a CYP3A4 inhibitor
- Initiate life-threatening ventricular arrhythmia treatment in hospital
Available strengths
- tab 150, 225, 300 mg
- ER cap 225, 325, 425 mg
Contraindications
- Heart failure
- Cardiogenic shock
- SA, AV, and intraventricular disorders of impulse generation/conduction without a pacemaker
- Known Brugada syndrome
- Bradycardia
- Marked hypotension
- Bronchospastic disorders or severe obstructive pulmonary disease
- Marked electrolyte imbalance
Cautions
- Proarrhythmia
- May unmask Brugada syndrome
- Avoid with other QT-prolonging drugs
- May provoke heart failure
- Conduction disturbances/AV block
- Agranulocytosis
- May exacerbate myasthenia gravis
Adverse reactions
- Unusual taste
- Nausea/vomiting
- Dizziness
- Constipation
- Headache
- Fatigue
- First-degree AV block
- Intraventricular conduction delay
Pregnancy No identified drug-associated risks in humans; animal adverse developmental outcomes at maternally toxic doses.
Lactation Undefined.
Cost
Generic entry2000
⚠ BOXED WARNING
- Proarrhythmia and excess mortality after myocardial infarction
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityProarrhythmia and sodium-channel blockade can cause wide-complex dysrhythmia and cardiogenic shock.
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