What is the typical dosing regimen for amiodarone (antiarrhythmic medication) via intravenous (IV) drip for an adult patient with no significant contraindications, requiring acute management of life-threatening arrhythmias?

Amiodarone IV Drip Dosing for Life-Threatening Arrhythmias

For acute management of life-threatening ventricular arrhythmias in adults, administer amiodarone as a 150 mg IV bolus over 10 minutes, followed by 1 mg/min infusion for 6 hours (360 mg), then 0.5 mg/min for the remaining 18 hours (540 mg), with a maximum total dose of 2.2 g over 24 hours. 1, 2, 3

Standard Infusion Protocol

Initial Loading Dose

• Administer 150 mg IV over 10 minutes as the rapid loading dose, diluted in 100 mL D5W 2, 3
• This initial bolus can be repeated once if breakthrough VF or hemodynamically unstable VT occurs during treatment 2, 3

Maintenance Infusion Sequence

• First 6 hours: Infuse at 1 mg/min (total 360 mg) 1, 2, 3
• Remaining 18 hours: Reduce to 0.5 mg/min (total 540 mg) 1, 2, 3
• Total 24-hour dose: Approximately 1,050 mg (including initial bolus) 2, 3

Extended Maintenance Beyond 24 Hours

• Continue at 0.5 mg/min (720 mg per 24 hours) for up to 2-3 weeks if needed 3
• The maintenance infusion rate may be increased to achieve effective arrhythmia suppression, but doses above 2,100 mg/day increase hypotension risk 3

Cardiac Arrest Protocol (VF/Pulseless VT)

For cardiac arrest with VF or pulseless VT unresponsive to defibrillation and epinephrine, use a different dosing strategy:

• Administer 300 mg IV/IO bolus over 10 minutes 4, 2
• If the rhythm persists, give a second dose of 150 mg IV/IO 4, 2
• This is specifically for arrest situations where the patient has no pulse 4

Critical Administration Requirements

Vascular Access and Concentration Limits

• Use a central venous catheter for concentrations >2 mg/mL 2, 3
• For peripheral IV access, do not exceed 2 mg/mL concentration for infusions longer than 1 hour 3
• Concentrations >3 mg/mL cause high incidence of peripheral vein phlebitis 3
• Always use a volumetric infusion pump—drop counter sets can underdose by up to 30% 3

Equipment and Solution Preparation

• Use an in-line filter during administration 3
• Administer in glass or polyolefin bottles containing D5W for infusions exceeding 2 hours 3
• Do not use evacuated glass containers for admixing due to precipitation risk 3
• Inspect solution for particulate matter and discoloration before administration 3

Monitoring Requirements

Cardiovascular Monitoring

• Hypotension occurs in 16% of IV patients—monitor blood pressure continuously during loading 2
• Bradycardia occurs in 4.9% of IV patients—watch for heart rate <60 bpm 2
• Monitor for AV block and heart block development 2
• Check QT interval for excessive prolongation 2

Continuous Surveillance

• Maintain continuous ECG monitoring throughout infusion 2
• Have defibrillator immediately available 2
• Monitor for phlebitis at infusion site if using peripheral access 2

Absolute Contraindications

Do not administer amiodarone in the following situations without a functioning pacemaker:

• Second- or third-degree AV block 2
• Sick sinus syndrome 2
• Severe sinus node dysfunction 2

Additional contraindications:

• Acute inflammatory lung disease 2
• Patients who have had heart transplant 2

Critical Drug Interactions During IV Infusion

Immediate Dose Adjustments Required

• Digoxin: Reduce dose by 50% immediately—amiodarone doubles digoxin levels 2
• Warfarin: Reduce dose by 33-50% and monitor INR at least weekly (interaction peaks at 7 weeks) 2
• Avoid concomitant QT-prolonging drugs without expert consultation 2

Y-Site Incompatibilities

• Amiodarone forms precipitates with multiple drugs—use separate IV lines for coadministration of incompatible medications 3

Special Considerations for High-Risk Patients

Hepatic Dysfunction

• Use with extreme caution in patients with hepatic impairment 2
• Intravenous amiodarone at concentrations and rates exceeding recommendations has caused hepatocellular necrosis and death 3

Elderly Patients

• Close clinical monitoring is particularly important in elderly patients 3
• Consider lower maintenance infusion rates if adverse effects develop 3

Common Pitfalls to Avoid

• Never exceed initial infusion rate of 30 mg/min—this increases risk of severe hypotension 3
• Do not use PVC containers in series connections due to air embolism risk 3
• Remember that amiodarone's antiarrhythmic effect may take up to 30 minutes to develop 4
• The onset of IV amiodarone is rapid (typically <30 minutes), much faster than the older literature suggesting 30-minute delays 1

Supplemental Dosing for Breakthrough Arrhythmias

• For breakthrough VF or hemodynamically unstable VT during maintenance infusion, administer 150 mg supplemental bolus mixed in 100 mL D5W over 10 minutes 3
• Infuse slowly to minimize hypotension risk 3