About This Calculator

The Amiodarone Infusion Calculator helps clinicians determine the correct intravenous (IV) dosing and infusion rates based on established Advanced Cardiovascular Life Support (ACLS) guidelines. It simplifies complex calculations for both emergent cardiac arrest situations and the management of stable tachyarrhythmias, ensuring adherence to recommended protocols.

Outputs Explained

The tool provides tailored outputs based on the selected clinical indication:

• For Cardiac Arrest (Pulseless VT/VF): The calculator provides the standard fixed doses for the initial and subsequent boluses as per ACLS algorithms. No patient weight is required for this indication.
• For Stable Tachyarrhythmia: The calculator outputs a multi-part infusion schedule, including the initial loading dose rate (typically over 10 minutes) and subsequent maintenance infusion rates for the first 6 hours and the following 18 hours. These rates are calculated in mL/hr based on the patient's weight and the specified amiodarone concentration.

How to Use the Calculator

1. Select Indication/Protocol: Choose either "Cardiac Arrest" for pulseless ventricular tachycardia/fibrillation or "Stable Tachyarrhythmia" for patients with a pulse who require rate or rhythm control.
2. Enter Patient Weight: For the "Stable Tachyarrhythmia" protocol, input the patient's weight and select the unit (kg or lbs). This step is hidden and not required for the cardiac arrest protocol.
3. Select Infusion Concentration: Choose from a list of standard premixed bag concentrations (e.g., 450 mg in 250 mL) or select "Custom" to input the total drug amount (mg) and total solution volume (mL) for your institution's specific formulation.
4. Calculate: The tool will display the appropriate dosing recommendations based on your inputs.

Dosing Overview

Amiodarone administration follows distinct protocols based on patient stability and cardiac rhythm.

Pulseless Ventricular Fibrillation / Tachycardia (Cardiac Arrest):

• Initial Dose: 300 mg IV/IO push.
• Second Dose: If rhythm persists, a second dose of 150 mg IV/IO push may be administered.

Stable Wide-Complex Tachycardia:

• Loading Infusion: 150 mg infused over 10 minutes (rate of 15 mg/min). This is typically prepared as 150 mg in 100 mL D5W.
• Maintenance Infusion (Part 1): 1 mg/min for the first 6 hours.
• Maintenance Infusion (Part 2): 0.5 mg/min for the subsequent 18 hours.

The maximum cumulative dose in a 24-hour period should not exceed 2.2 grams.

Switching from IV to Oral Therapy

When transitioning a patient from an intravenous amiodarone infusion to an oral dosing schedule, careful planning is required to maintain therapeutic levels. The approach depends on the duration of the IV infusion.

• For infusions < 1 week: A typical oral loading dose is 800-1600 mg/day, divided into multiple doses, until a total loading dose of 10 grams is achieved.
• For infusions > 1 week: A lower initial oral loading dose of 400-600 mg/day may be appropriate.

Coordination with a pharmacist and cardiologist is highly recommended to ensure a safe transition based on the individual patient's clinical status.

Managing a Missed or Interrupted Dose

For a continuous maintenance infusion, any interruption should be addressed promptly. If the infusion is stopped for a short period, it can typically be restarted at the previously prescribed rate. For longer interruptions, the patient's clinical status and cardiac rhythm must be reassessed. The prescribing provider should be consulted to determine if a supplemental bolus or rate adjustment is necessary.

Safety Alerts & Administration

• Hypotension and Bradycardia: These are the most common adverse effects. Slowing the infusion rate can often mitigate these effects. Continuous cardiac and hemodynamic monitoring is essential.
• Phlebitis: Amiodarone is an irritant to peripheral veins. Administration through a central venous catheter is strongly preferred, especially for concentrations >2 mg/mL or for long-duration infusions.
• In-line Filter: Always use a 0.22-micron in-line filter during administration.
• Diluent: Amiodarone is compatible with Dextrose 5% in Water (D5W) only. Do not use saline unless specified by the manufacturer for certain formulations.
• Incompatibilities: Amiodarone is incompatible with heparin and sodium bicarbonate, among other medications. Always flush the line before and after administration.

Frequently Asked Questions (FAQ)

1. Why is patient weight required for stable tachycardia but not for cardiac arrest?
   In cardiac arrest, the immediate goal is to restore circulation, and a standardized, high-dose bolus is used for maximal effect. In stable patients, dosing is more nuanced to balance efficacy with the risk of side effects like hypotension, so a weight-based maintenance infusion is not standard, but the loading dose is fixed. The maintenance dose is a standard rate (1 mg/min then 0.5 mg/min), not weight-based. The tool includes weight for context and potential local protocols, though ACLS itself uses fixed rates.
2. What is the standard concentration for an amiodarone drip?
   A common concentration is 1.8 mg/mL (e.g., 450 mg in 250 mL D5W or 900 mg in 500 mL D5W). However, concentrations can vary by institution.
3. Why must the loading dose for stable tachycardia be given over 10 minutes?
   A rapid IV push of amiodarone in a patient with a pulse can cause profound hypotension and bradycardia. Infusing the 150 mg load over 10 minutes minimizes these hemodynamic risks.
4. What should I do if my institution uses a concentration not listed?
   Select the "Custom..." option in the calculator. This will allow you to enter the exact amount of drug (in mg) and the total volume of the solution (in mL) to calculate the correct rate.
5. Can I administer amiodarone through a peripheral IV line?
   While a bolus can be given via a large, well-established peripheral IV, continuous infusions should be administered through a central line whenever possible to prevent phlebitis and extravasation.
6. What is the maximum 24-hour dose of amiodarone?
   The total cumulative IV and oral dose should not exceed 2.2 grams in the first 24 hours.
7. Does amiodarone require a special type of IV bag or tubing?
   Yes, amiodarone can be adsorbed into polyvinyl chloride (PVC) tubing and bags. It is recommended to use glass or polyolefin containers and dedicated administration sets.
8. Is this calculator a substitute for clinical judgment or ACLS certification?
   No. This tool is for educational and informational purposes only. It is intended to support, not replace, the judgment of a qualified healthcare professional and current ACLS guidelines. All calculations should be independently verified before administration.

References

1. Panchal, A. R., et al. (2020). Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation, 142(16_suppl_2), S366–S468. View Guideline
2. U.S. Food and Drug Administration. (2022). Highlights of Prescribing Information: Amiodarone Hydrochloride Injection, USP. Drugs@FDA. View FDA Label
3. National Center for Biotechnology Information. PubChem Compound Summary for CID 2157, Amiodarone. View at PubChem