From the Guidelines
The loading dose for amiodarone is typically 150 mg given intravenously over 10 minutes, followed by a 1 mg/minute infusion for 6 hours, then 0.5 mg/minute for the remaining 18 hours, as recommended by the most recent guidelines 1.
Key Considerations
- For oral loading, 400-600 mg daily is given in divided doses for 2-4 weeks, followed by a maintenance dose of 100-200 mg daily, as outlined in the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.
- When administering IV amiodarone, use a central line when possible to avoid phlebitis, and monitor for hypotension which can occur with rapid administration.
- ECG monitoring is essential during loading to detect QT prolongation or bradycardia.
- Amiodarone works by blocking potassium channels to prolong action potential and has sodium and calcium channel blocking properties, making it effective for both ventricular and supraventricular arrhythmias.
Important Safety Information
- The total dose over 24 hours should not exceed 2.2 g, as specified in the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1.
- Amiodarone has a long half-life (25-100 days), which means tissue accumulation occurs gradually, explaining the need for loading doses to achieve therapeutic effects quickly.
- Potential adverse effects include bradycardia, hypotension, phlebitis, and QT prolongation, as noted in the guidelines 1.
From the FDA Drug Label
• Initial Load: 150 mg in 100 mL (in D 5W) infused over 10 minutes The loading dose for amiodarone is 150 mg infused over 10 minutes 2.
- The initial load can be repeated for breakthrough episodes of VF or hemodynamically unstable VT.
From the Research
Amiodarone Loading Dose
- The loading dose for amiodarone is not explicitly stated in studies 3 and 4, which provide general information about the medication's use, side effects, and interactions.
- However, a study from 1992 5 describes a high-dose oral loading regimen, where patients received 50 mg/kg per day of amiodarone for 3 days, followed by 30 mg/kg per day for 2 days, and then maintenance therapy of 300 to 400 mg twice daily.
- This loading dose was found to be well-tolerated in 15 out of 16 patients, with significant increases in ventricular tachycardia cycle length and right ventricular effective refractory period starting on day 1.
- Other studies 6 and 7 do not provide specific information about the loading dose, focusing instead on monitoring protocols, side effects, and the antiarrhythmic efficacy of amiodarone.