AMIODARONE (CORDARONE)

Class

Antiarrhythmic agent

Pharmacology and Actions

1. Suppresses ventricular ectopy and increases ventricular fibrillation threshold.
2. Noncompetitive blocker of alpha and beta adrenergic receptors which can cause:
   1. Negative chronotropic effects
   2. Negative inotropic effects (the effect on cardiac output by the negative inotropic effect is balanced by a decrease in afterload and increase in coronary blood flow, which in turn improves cardiac performance [especially for patients with left ventricular failure]).
   3. Peripheral vasodilation (reduces afterload).
   4. Coronary vessel dilation
3. Prolongs duration of cardiac potential and prolongs effective refractory period

Indications

1. Shock resistant ventricular fibrillation or pulseless ventricular tachycardia
2. Unstable ventricular tachycardia
3. May be used for rate control in treatment of symptomatic atrial fibrillation or flutter when other therapies are ineffective.

Contraindications

1. None in cardiac arrest with ventricular fibrillation or pulseless ventricular tachycardia
2. 2^nd or 3^rd  degree heart block in the absence of functioning pacemaker
3. Marked bradycardia
4. Cardiogenic shock
5. Known hypersensitivity

Precautions

1. Increased hypotension and bradycardia can occur when given with other beta­-blockers or calcium channel blockers.
2. May prolong QT interval. Do not administer with other medications that prolong QT interval (e.g., procainamide).
3. Use with caution if renal failure is present, terminal elimination of amiodarone is extremely long (half-life can last up to 40 days).

Administration

1. Pulseless VT / VF: 300 mg IV/IO push. Consider repeating 150 mg IV/IO push in 3-5 minutes (Maximum cumulative dose is 2.2 grams IV over 24 hours).
2. Unstable VT: 150 mg slow IV/IO push over 10 minutes.  Consider repeating at same dose.

Side Effects and Special Notes

1. Medication must be carefully and slowly drawn from vial to avoid excess air bubbles.
2. The most commonly reported side effects include hypotension, bradycardia, AV block, PEA, and hepatoxicity.