Can amiodarone be administered to an adult with hypotensive ventricular tachycardia that is refractory to electrical cardioversion?

Amiodarone in Hypotensive Ventricular Tachycardia

Yes, amiodarone can and should be administered to patients with hypotensive ventricular tachycardia that is refractory to electrical cardioversion, as it is FDA-approved specifically for this indication and supported by guideline recommendations. 1

FDA-Approved Indication

• Amiodarone IV is explicitly indicated for hemodynamically unstable ventricular tachycardia (VT) in patients refractory to other therapy, making hypotensive VT a primary indication rather than a contraindication 1
• The FDA label specifies use for "frequently recurring ventricular fibrillation and hemodynamically unstable ventricular tachycardia" 1

Guideline Recommendations for Shock-Refractory VT

• Amiodarone may be considered for VF/pVT refractory to CPR, defibrillation, and vasopressors (Class IIb recommendation) 2
• The 2018 AHA guidelines support amiodarone use after at least 1 failed shock and epinephrine administration in shock-refractory ventricular arrhythmias 3
• The primary objective is to facilitate successful defibrillation and reduce recurrent arrhythmias, not to pharmacologically convert the rhythm 3

Dosing Strategy

• Initial dose: 300 mg IV/IO bolus for shock-refractory VT/VF 2
• Alternative dosing: 5 mg/kg IV over 30 minutes followed by continuous infusion 3
• Administer the 150 mg loading dose diluted to 1.5 mg/ml over 10 minutes minimum to reduce hypotension risk 4

Critical Hypotension Considerations

Understanding the Risk

• Hypotension occurs in approximately 16% of patients receiving IV amiodarone, primarily due to vasoactive solvents causing vasodilation rather than negative inotropy 4
• The polysorbate formulation is more likely to cause hypotension than the captisol-based formulation 3
• The rate of infusion is more important than dose in determining hypotension risk 4

Management Algorithm

If hypotension develops during amiodarone administration:

• First step: Slow or temporarily discontinue the amiodarone infusion 4
• Continue vasopressor support (epinephrine already being given during cardiac arrest) 2
• Resume at slower infusion rate once blood pressure stabilizes 4

When Hypotension is NOT a Contraindication

• Pre-existing hypotension from the unstable VT itself does not contraindicate amiodarone use - the drug is specifically indicated for hemodynamically unstable VT 1
• In the cardiac arrest setting with ongoing CPR, the benefits of rhythm control outweigh hypotension concerns 3
• Clinical trials demonstrating efficacy specifically enrolled patients with shock-refractory VF/pVT who had already received multiple shocks and epinephrine 3

Evidence from Clinical Trials

• The ARREST and ALIVE trials showed amiodarone improved survival to hospital admission in shock-refractory VF/pVT compared to placebo or lidocaine 3
• The ROC-ALPS trial found survival to hospital admission was higher with amiodarone compared to placebo, though no difference in long-term survival 3
• A prospective multicenter trial of 273 patients with recurrent hypotensive ventricular tachyarrhythmias showed a 40.3% response rate with IV amiodarone 5

Important Caveats

• Do not combine amiodarone with lidocaine - use one or the other, never both simultaneously, due to increased risk of adverse cardiovascular effects and QT prolongation 2
• Establishing vascular access should not compromise CPR quality or timely defibrillation 3
• Amiodarone is contraindicated only in patients with bradycardia or heart block without a pacemaker - not in hypotensive VT 4
• Monitor for bradycardia and heart block, which occur in 4.9% of patients receiving IV amiodarone 4

Clinical Context

• Most patients will require amiodarone therapy for 48 to 96 hours until ventricular arrhythmias are stabilized, though it may be safely administered for longer if necessary 1
• Research shows intravenous amiodarone can be used safely in patients with congestive heart failure, bundle branch block, or acute myocardial infarction with appropriate monitoring 6
• The hypotension risk should not deter use in the acute setting of refractory hypotensive VT, as this is the exact population for which the drug is indicated and studied 1, 5