Drug Card: Amiodarone

Amiodarone

An antiarrhythmic medication used for life-threatening ventricular arrhythmias and atrial fibrillation.

Ventricular Fibrillation (VF)

A life-threatening arrhythmia treated with amiodarone.

Ventricular Tachycardia (VT)

Another serious arrhythmia for which amiodarone is indicated.

Atrial Fibrillation (AF)

A cardiac condition that amiodarone can effectively treat.

Mechanism of Action

Prolongs myocardial cell action potential and refractory period, stabilizing heart rhythm.

Bioavailability

The absorption of amiodarone varies significantly, ranging from 20-50%.

Lipid-Soluble

Amiodarone's high lipid solubility leads to a large volume of distribution and tissue accumulation.

Cytochrome P450

Amiodarone is primarily metabolized by the liver using CYP3A4 enzymes.

Excretion

Amiodarone is excreted in feces and urine, with a long half-life due to tissue storage.

Contraindications

Includes known hypersensitivity, severe bradycardia, heart block, and cardiogenic shock.

Side Effects

Common adverse reactions include hypotension, bradycardia, thyroid dysfunction, pulmonary toxicity, and liver toxicity.

Dosage for VF

300 mg IV push for ventricular fibrillation, with a possible repeat of 150 mg.

Dosage for VT

150 mg IV over 10 minutes, followed by a 1 mg/min infusion for the first 6 hours.

Monitoring

Cardiac rhythm, blood pressure, and vital signs should be closely monitored during administration.

Drug Interactions

Amiodarone may interact with anticoagulants, digoxin, and other antiarrhythmics, increasing risks.

Grapefruit Juice

Can increase amiodarone levels by inhibiting its metabolism.