Amiodarone Loading Regimen
Amiodarone has a massive volume of distribution and a very long half-life. To achieve therapeutic concentrations rapidly, a cumulative loading dose (typically 10g total) is required before transitioning to a 200mg daily maintenance dose.
Standard Oral Loading Regimen
Days 1 to 7: 200 mg THREE times a day (Total: 600mg/day)
Days 8 to 14: 200 mg TWO times a day (Total: 400mg/day)
Day 15 onwards: 200 mg ONCE a day (Maintenance)
Total Cumulative Dose: (600 x 7) + (400 x 7) = 4,200 mg + 2,800 mg = 7,000 mg (7g). The remaining 3g to reach 10g tissue saturation is accumulated during the first few weeks of maintenance therapy.
Standard IV Loading Regimen (Central Line)
Amiodarone is highly phlebitic. Continuous infusions should be administered via a central venous catheter (CVC).
Initial phase (Stat): 5 mg/kg over 20 - 120 minutes. (Usually approx 300mg in 250mL 5% Glucose).
Followed by (24h infusion): 900 mg in 500mL 5% Glucose over 24 hours.
Transition: Switch to oral therapy as soon as clinically stable. Do not exceed 1,200 mg IV in 24 hours.
Note: IV Amiodarone is incompatible with saline (0.9% NaCl). Must be mixed in 5% Glucose.
Monitoring Requirements
- Baseline: LFTs, U&Es, TFTs, Chest X-ray.
- Ongoing (Every 6 months): LFTs, TFTs (Hyper/Hypothyroidism).
- Interactions: Potent enzyme inhibitor. Halve the dose of Digoxin. Halve the dose of Warfarin (and monitor INR closely). Max dose of Simvastatin is 20mg.