Propafenone

Classification:

Class IC – Sodium (Na⁺) channel blockers

Propafenone – slows conduction in atrial myocardium and is also a non-selective beta-blocker
Flecainide – slows conduction in atrial myocardium

Diagram of the effect of propafenone as a class IC antiarrhythmic illustrating use-dependent sodium channel blockade, reduced myocardial excitability, and pharmacological cardioversion of atrial fibrillation to sinus rhythm.

Mechanism:

Slows conduction in myocardium, reduces myocardial excitability and automaticity

Inhibits the non-nodal action potential (in myocardium)

Is use-dependent (effect increases at heart rate > 90/min.)
Is a weak non-selective beta-blocker

The beta-blocking effect increases with higher doses of propafenone

Effect on AF:

Maintenance of sinus rhythm – prevents recurrence of atrial fibrillation (AF)
Cardioversion of AF to sinus rhythm – termination of the AF episode and restoration of sinus rhythm

“Pill in the pocket” strategy – single oral dose of propafenone taken at home at the onset of an AF episode.

The goal is restoration of sinus rhythm

Propafenone and atrial fibrillation (AF)
Brand names
Rytmonorm, Rythmol, Arythmol, Cuxafenon, Nistaken, Propafenon Hexal, Jutanorm
Indications
Acute cardioversion of AF to sinus rhythm “Pill in the pocket” strategy Maintenance of sinus rhythm
Dosing
Acute cardioversion of AF to sinus rhythm (intravenous) 1–2 mg/kg – approximately 70–150 mg intravenous over 10 minutes Acute cardioversion of AF to sinus rhythm (oral) – “pill in the pocket” strategy 450 mg (< 70 kg) – immediate-release 600 mg (> 70 kg) – immediate-release Chronic rhythm control – maintenance of sinus rhythm (oral) 150–300 mg three times daily – immediate-release 225–425 mg twice daily – prolonged-release
Onset of action
< 6 hours (intravenous) < 8 hours (oral)
Effect
Time to conversion to sinus rhythm and success rate < 6 hours – 43–89 % (intravenous) < 3 hours – 45–55 % (oral) 3–8 hours – 69–78 % (oral) Maintenance of sinus rhythm (paroxysmal or persistent AF) at 1 year 40–60 % (oral)
Duration of action
2–6 hours (intravenous) 6–12 hours (oral) – immediate-release 10–24 hours (oral) – prolonged-release
Contraindications
Atrial flutter (propafenone must not be administered for cardioversion) AV block II–III degree Bradycardia (< 50/min.) Hypotension (< 90 mmHg) Severe electrolyte imbalance (Na⁺, K⁺, Mg²⁺) Myocardial infarction (within the last 3 months) Cardiogenic shock Ejection fraction < 40 % Severe structural heart disease Brugada syndrome Sick sinus syndrome (without pacemaker) Severe COPD Severe hepatic impairment Myasthenia gravis Concomitant use of ritonavir Allergy to propafenone

Patient monitoring after initiation of propafenone:

Discontinue if contraindications occur
Discontinue or reduce the dose if adverse effects occur

Patient monitoring after initiation of propafenone
Time since initiation	What to monitor	Reason for treatment interruption
Week 1	ECG (QRS, PR interval) Blood pressure	QRS > 120 ms or prolongation > 25 % Bradycardia < 50/min Hypotension < 90/60 mmHg Brugada pattern on ECG
Month 1	ECG (QRS, PR interval)	QRS > 120 ms or prolongation > 25 % Brugada pattern on ECG
6–12 months	ECG (QRS, PR interval) Laboratory tests Echocardiography Holter ECG as needed	Ejection fraction < 40 % QRS > 120 ms or prolongation > 25 % Brugada pattern on ECG Severe laboratory abnormalities

Adverse effects:

Very common (> 10 %):

Nausea
Vomiting
Taste disturbance

Common (1–10 %):

Chest pain, oedema
Deblocked atrial flutter (1:1 conduction)
AV block (I and II degree)
Heart failure
Hypotension
Bradycardia
Ventricular arrhythmia
Haematomas
Anorexia
Constipation, diarrhoea, flatulence
Dry mouth
Haematuria
Weakness
Depression
Dizziness
Somnolence
Headache
Tremor
Blurred vision
Dyspnoea

Uncommon (< 1 %):

AV block III degree
Alopecia
Cholestasis
Gastroenteritis
Impotence
Agranulocytosis
Anaemia
Thrombocytopenia
Hepatitis
Seizures
Visual disturbances
Tinnitus
Nephrotic syndrome

Propafenone and flecainide belong to Class IC anti-arrhythmic drugs, but they are different molecules.

Therefore, their properties differ in part.

Propafenone vs. flecainide in atrial fibrillation (AF)
Characteristic	Propafenone	Flecainide
Mechanism of action	Na⁺ channel blockade + weak beta-blocking effect	Na⁺ channel blockade, without beta-blocking effect
Effect on AV node	Mild slowing of conduction (via beta-blockade)	Virtually no direct effect
Use in AF	Acute cardioversion, maintenance of sinus rhythm, partial rate control	Acute cardioversion, maintenance of sinus rhythm (combination with BB/non-DHP CCB recommended)
Efficacy at 1 year	~40–60 % maintenance of sinus rhythm	~50–65 % maintenance of sinus rhythm
Effect on heart rate	Reduces (due to beta-blockade)	No effect
Use-dependence	Less pronounced; partially attenuated by beta-blocking effect	Pronounced, marked QRS prolongation at higher heart rates
Adverse effects	Nausea, metallic taste, bradycardia, hypotension	Dizziness, visual disturbances

BB – beta-blockers, non-DHP CCB – non-dihydropyridine calcium channel blockers