Intravenous Amiodarone Infusion Protocol

Dosing Regimen

• Loading dose: Administer a 150 mg IV bolus over 10 minutes; a repeat bolus may be given after 10–30 minutes for breakthrough arrhythmias. This is followed by a rapid infusion of 1 mg/min for 6 hours (≈360 mg) and then a slower infusion of 0.5 mg/min for the next 18 hours (≈540 mg), delivering roughly 1 g of amiodarone in the first 24 hours. 1

• Breakthrough arrhythmia supplement: Give an additional 150 mg bolus diluted in 100 mL D5W over 10 minutes if arrhythmia recurs during the loading phase. 3

• Transition to oral therapy:

  • If IV therapy lasts < 1 week, start oral amiodarone 800–1600 mg/day.
  • If IV therapy lasts 1–3 weeks, start oral amiodarone 600–800 mg/day.
  • If IV therapy lasts > 3 weeks, start oral amiodarone 400 mg/day.
  • Continue oral dosing until a cumulative loading dose of 10 g is reached, then maintain with 200–400 mg/day. 6

Administration Requirements

• Route: Use a central venous catheter whenever feasible to minimize peripheral phlebitis risk. 4

• Delivery device: Employ a volumetric infusion pump; drop‑counter sets can underdose by up to 30 %.

Monitoring Protocol

• Continuous cardiac monitoring for bradycardia and heart block throughout the infusion. 5

• Blood pressure monitoring because hypotension occurs in about 16 % of patients; reduce or stop the infusion immediately if hypotension or significant bradycardia develops. 4

• Baseline assessments before initiation:

  • Detailed cardiac history (heart failure, arrhythmia symptoms, concomitant drugs).
  • Chest radiograph.
  • Thyroid function tests and liver transaminases.
  • Pulmonary function testing including diffusion capacity.
  • Digoxin level and PT/INR (if on warfarin).
  • Ophthalmologic exam for patients with pre‑existing visual impairment. All baseline items are recommended prior to starting IV amiodarone. 5

• During the first week: Close surveillance of heart rate and vigilance for anticipated adverse effects. 4

Contraindications & Adverse Effects

• Absolute contraindications:

  • Second‑ or third‑degree atrioventricular block without a pacemaker.
  • Symptomatic bradycardia without a pacemaker. 5

• Key adverse effects observed with IV administration:

  • Hypotension in ~16 % of patients.
  • Bradycardia or heart block in ~4.9 % of patients.
  • Phlebitis is common with peripheral administration. 4

Drug Interactions

• Warfarin: Amiodarone decreases warfarin clearance, causing abrupt INR rises; monitor PT/INR at least weekly for the first 6 weeks, with peak interaction around week 7. 5

• Digoxin: Co‑administration roughly doubles digoxin serum concentrations; monitor digoxin levels and adjust dose if toxicity is suspected. 4