What is the dose of a 'pill in the pocket' (emergency medication), such as metoprolol (beta-blocker), for atrial fibrillation?

Pill-in-the-Pocket Dosing for Atrial Fibrillation

For self-administered cardioversion of paroxysmal atrial fibrillation, use flecainide 200-300 mg as a single oral dose OR propafenone 450-600 mg as a single oral dose, but only after safety has been confirmed in a monitored hospital setting first. 1

Specific Dosing Regimens

Flecainide

• Single oral dose: 200-300 mg 1
• No follow-up dose needed 1
• Mean time to conversion: approximately 2 hours 1

Propafenone

• Single oral dose: 450-600 mg 1
• No follow-up dose needed 1
• Similar conversion time to flecainide 1

Critical Pre-Treatment Requirements

Before any out-of-hospital use, you must:

• Administer the first dose in a monitored hospital setting to establish safety 1
• Pre-treat with a beta-blocker or non-dihydropyridine calcium channel blocker at least 30 minutes before the Class IC agent to prevent rapid 1:1 AV conduction if atrial flutter develops 1
• Alternatively, maintain continuous background therapy with AV nodal blocking agents 1

Absolute Contraindications (Do Not Use)

These patients should never receive pill-in-the-pocket Class IC drugs:

• Any coronary artery disease (CAD) of any severity 1, 2
• Significant structural heart disease 1
• Left ventricular dysfunction or reduced ejection fraction 1, 2
• NYHA Class III-IV heart failure 2
• Sinus or AV node dysfunction 1
• Bundle branch block 1
• QT interval prolongation 1
• Brugada syndrome 1
• Marked left ventricular hypertrophy (wall thickness >1.4 cm) 2

Safety Data from Real-World Use

Adverse events occur in approximately 3% of patients: 3

• Significant events include unexplained syncope, symptomatic bradycardia/hypotension, and 1:1 atrial flutter 3
• All significant adverse events occurred with flecainide 300 mg or propafenone 600 mg (the higher end of dosing ranges) 3
• Two patients required permanent pacemakers for bradycardia 3
• Electrical cardioversion was needed in 11% due to drug failure 3

Important Clinical Pitfalls

Common mistakes to avoid:

• Never initiate without the supervised hospital trial first - even though 38% of patients in contemporary practice skip this step, guidelines uniformly require it due to rare but serious complications 1, 3
• Never use in patients with any degree of CAD - this is an absolute contraindication per European Society of Cardiology guidelines, yet is frequently overlooked 2
• Never give Class IC agents without prior or concurrent AV nodal blockade - this prevents the dangerous complication of 1:1 atrial flutter with rapid ventricular response 1

Efficacy Expectations

When used appropriately, pill-in-the-pocket therapy:

• Achieves successful conversion in approximately 94% of episodes 1
• Reduces emergency department visits and hospitalizations 1
• Provides patient autonomy and reassurance for selected individuals 1
• Is marginally less effective than hospital-based cardioversion but far more practical 1

Note on Metoprolol

Metoprolol is NOT used as a pill-in-the-pocket agent for cardioversion. 4, 5 Beta-blockers like metoprolol are used for rate control in chronic atrial fibrillation or for maintaining sinus rhythm after cardioversion, but they do not reliably terminate acute AF episodes and are not part of the pill-in-the-pocket strategy 1, 4, 5