What are the effects of administering Amiodarone (antiarrhythmic medication) intravenously (IV)?

From the Guidelines

Amiodarone can be administered as an IV push in emergency situations, particularly for life-threatening ventricular arrhythmias, with a recommended loading dose of 300 mg IV/IO, which can be followed by a second dose of 150 mg IV/IO if needed, as supported by the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1.

Key Considerations

• The administration of IV amiodarone affects sodium, potassium, and calcium channels and has beta-adrenergic blocking properties, making it effective for treating VF or pulseless VT unresponsive to shock delivery, CPR, and a vasopressor 1.
• The use of amiodarone in the out-of-hospital setting has been shown to improve hospital admission rates when compared with administration of placebo or lidocaine 1.
• Potential adverse effects of IV amiodarone include hypotension, bradycardia, and QT prolongation, emphasizing the need for close monitoring during administration 1.

Administration Guidelines

• For cardiac arrest with ventricular fibrillation or pulseless ventricular tachycardia, a 300 mg rapid IV push is appropriate, with a possible second dose of 150 mg if needed 1.
• When administering IV push amiodarone, use a central line if available to minimize phlebitis, and dilute with D5W rather than normal saline to prevent precipitation 1.
• Continuous cardiac monitoring is essential during and after amiodarone administration to promptly identify any adverse effects or arrhythmia recurrence 1.

Mechanism of Action

• Amiodarone works by blocking potassium channels, prolonging action potential duration, and extending the refractory period in cardiac tissue, which helps suppress arrhythmias 1.
• It also has sodium and calcium channel blocking properties and noncompetitive beta-blocking effects, making it effective for various arrhythmias but also increasing the risk of side effects 1.

From the FDA Drug Label

12.3 Pharmacokinetics

Disposition Amiodarone exhibits complex disposition characteristics after intravenous administration. Peak serum concentrations after single 5 mg/kg 15-minute intravenous infusions in healthy subjects range between 5 mg/L and 41 mg/L Peak concentrations after 10-minute infusions of 150 mg intravenous amiodarone in patients with ventricular fibrillation (VF) or hemodynamically unstable ventricular tachycardia (VT) range between 7 mg/L and 26 mg/L.

Administration of Amiodarone via IV Push:

• The FDA drug label does not provide specific guidance on the administration of amiodarone via IV push.
• However, it does provide information on intravenous administration, including peak serum concentrations after single 5 mg/kg 15-minute intravenous infusions and 10-minute infusions of 150 mg intravenous amiodarone.
• Key Considerations:
  • Peak serum concentrations
  • Administration duration
  • Patient population (e.g., ventricular fibrillation or hemodynamically unstable ventricular tachycardia)
• Clinical Decision:
  • Given the lack of specific guidance on IV push administration, caution should be exercised when considering this route.
  • It is essential to carefully evaluate the patient's condition and the potential risks and benefits of IV push administration.
  • Consultation with a healthcare professional or further guidance from the manufacturer may be necessary 2.

From the Research

Amiodarone Administration

• Amiodarone can be administered intravenously (IV) for emergency situations, such as cardiac arrest with shockable rhythm, ventricular tachyarrhythmias, and atrial fibrillation 3, 4, 5.
• The IV administration of amiodarone is recommended for patients with hemodynamically stable ventricular tachycardia, polymorphic ventricular tachycardia, and wide-complex tachycardia of uncertain origin 3.

Dosage and Side Effects

• The dosage of amiodarone for IV administration varies, but it is typically given as a loading dose followed by a maintenance dose 3, 4, 6.
• Common side effects of amiodarone include hypotension, bradycardia, and peripheral phlebitis, while major contraindications include bradycardia, sinoatrial block, and severe conduction disturbances 3, 6.

Contraindications and Interactions

• Amiodarone is contraindicated in patients with certain conditions, such as hypotension, severe respiratory failure, hepatocellular failure, and hyperthyroidism 3, 6.
• Amiodarone interacts with several medications, including HMG-CoA reductase inhibitors, class I antiarrhythmic agents, and warfarin, which can increase the risk of adverse effects 3, 4, 6.

Efficacy and Outcomes

• Amiodarone has been shown to improve survival to hospital admission in patients with cardiac arrest due to ventricular fibrillation or pulseless ventricular tachycardia 5.
• Amiodarone also improves the restoration and maintenance of sinus rhythm after electrical cardioversion of atrial fibrillation, with a relatively low risk of adverse effects 7.