What is the preferred choice between procainamide and bretylium (anti-arrhythmic medications) in an elderly patient with a complex medical history, including conditions such as small bowel obstruction, during a cardiac arrest (code) situation?

Neither Procainamide nor Bretylium Should Be Used in Elderly Patients During Cardiac Arrest

Bretylium is no longer recommended for cardiac arrest, and procainamide should not be used as it is listed after lidocaine, bretylium, and magnesium in the treatment algorithm—making it a distant fourth-line option that has no proven survival benefit. 1

Current Evidence-Based Approach

Why Bretylium Is Obsolete

• Bretylium is explicitly no longer recommended for cardiac arrest management according to the European Society of Cardiology guidelines 1
• The 1996 ACC/AHA guidelines positioned bretylium as a second-line agent only after defibrillation, epinephrine, and lidocaine had failed to convert VF/pulseless VT 1
• Bretylium has potent antifibrillatory but weak antiarrhythmic effects, with a biphasic hemodynamic profile that causes initial hypertension followed by hypotension—particularly problematic in elderly patients 1

Why Procainamide Is Inappropriate During Codes

• Procainamide requires a slow infusion rate of 20 mg/min over 30-60 minutes, making it impractical during active cardiac arrest when time is critical 1
• The ACLS guidelines list procainamide as potential therapy for VF and pulseless VT only after lidocaine, bretylium, and magnesium have been considered—placing it as a fourth-line option 1
• In a 10-year observational study of 665 out-of-hospital VF/pulseless VT arrests, procainamide showed no association with survival to hospital discharge (OR = 1.02; 95% CI = 0.66 to 1.57) 2
• Procainamide may cause proarrhythmia including torsades de pointes, with patients having renal insufficiency (common in elderly) at increased risk due to accumulation of the active metabolite NAPA 1

What Should Be Used Instead

First-Line Antiarrhythmic: Amiodarone

• Amiodarone is the first choice in patients with VF/VT refractory to 3 initial shocks, with a starting dose of 300 mg IV diluted in 20 mL 5% dextrose 1
• Two randomized trials demonstrated benefit of amiodarone over standard care for shock-refractory VF/VT for survival to hospital admission, though not to discharge 1
• Amiodarone may be considered for refractory VT/VF according to the 2010 International Consensus on CPR 1

Alternative: Lidocaine

• Lidocaine is the traditional first antiarrhythmic agent recommended in cardiac arrest patients with persistent VT/VF despite defibrillation and epinephrine 1
• Initial bolus of 1.0 to 1.5 mg/kg (75-100 mg), with additional boluses of 0.5 to 0.75 mg/kg every 5-10 minutes up to 3 mg/kg total 1
• While there is inadequate evidence to definitively support lidocaine, it remains an acceptable alternative when amiodarone is unavailable 1

Critical Considerations for Elderly Patients

Altered Pharmacokinetics Demand Caution

• Elderly patients have decreased renal and hepatic clearance and altered volume of distribution, requiring lower starting doses and slower titration 1
• Drug therapy should be initiated at lower than usual doses with titration at longer intervals and smaller incremental increases 1
• Patients with renal insufficiency may develop high levels of procainamide's metabolite NAPA, increasing risk of torsades de pointes 1

Complex Medical History Compounds Risk

• In an elderly patient with small bowel obstruction, the risk of electrolyte abnormalities (hypokalemia, hypomagnesemia) increases proarrhythmic potential of Class IA agents like procainamide 1, 3
• Procainamide has a low toxic-to-therapeutic ratio and is associated with serious adverse effects, particularly problematic in elderly patients with multiple comorbidities 3
• Advanced age increases susceptibility to adverse cardiac events from antiarrhythmic drugs 1

Practical Algorithm for Cardiac Arrest in Elderly

1. Immediate CPR with high-quality chest compressions and defibrillation for VF/pulseless VT 1
2. Epinephrine 1 mg IV/IO every 3-5 minutes as the primary vasopressor 1
3. After 3 failed defibrillation attempts: Consider amiodarone 300 mg IV bolus 1
4. If amiodarone unavailable: Lidocaine 1.0-1.5 mg/kg IV bolus 1
5. Magnesium 8 mmol IV if suspicion of hypomagnesemia (especially with diuretic use or bowel obstruction) 1
6. Never use bretylium (no longer recommended) 1
7. Never use procainamide during active arrest (too slow to administer, no survival benefit, high risk in elderly) 1, 2

Common Pitfalls to Avoid

• Do not delay defibrillation to administer antiarrhythmic drugs—electrical therapy remains the definitive treatment for VF/pulseless VT 1
• Do not use procainamide's slow infusion rate (20 mg/min over 30-60 minutes) during active cardiac arrest when seconds matter 1
• Do not assume antiarrhythmic drugs improve survival—no antiarrhythmic agent has been proven to improve survival to hospital discharge 1, 4
• Do not forget to correct reversible causes (the H's and T's), particularly electrolyte abnormalities in a patient with bowel obstruction 5