Amiodarone
Classification
Antiarrhythmic
Indications
ACP: Ventricular fibrillation
ACP: Pulseless ventricular tachycardia
ACP: Unstable ventricular tachycardia
ACP: Recurrent ventricular tachycardia following cardioversion
Contraindications
- Hypersensitivity
- Cardiogenic shock
- Marked symptomatic sinus bradycardia
- Second or third-degree atrioventricular node block
Adult dosages
ACP: ventricular fibrillation and pulseless ventricular tachycardia
- 300 mg IV push; may repeat 150 mg IV after 10 minutes if VF/pVT persist
ACP: unstable ventricular tachycardia and recurrent ventricular tachycardia following cardioversion
- 150 mg IV over 10 minutes
ACP: stable monomorphic WCT, or symptomatic runs of WCT
- 150 mg IV over 10 minutes
- CliniCall consultation required prior to administration.
Pediatric Considerations And Dosing
Safety and efficacy in children has not been established.
CliniCall consultation required prior to administration to discuss treatment plan.
Preparation and Administration
Infusion
Adult and Pediatric standard concentration
- Mix 150mg in 250mL NS
Mechanism Of Action
Amiodarone is a Class III antiarrhythmic, but also possesses characteristics of all four Vaughn-Williams classes of medications. It blocks sodium channels in the heart, antagonizes beta adrenoreceptors to inhibit some sympathetic activity, produces negative chronotropic effects in nodal tissues, lengthens the cardiac action potential, and also slows conduction and prolongs refractoriness by blocking potassium channels.
Pharmacokinetics
Intravenous (bolus):
- Onset: 2 minutes
- Peak: 20 minutes
- Duration: 2 hours
Adverse Effects
- Hypotension is the most commonly reported side effect following intravenous administration
- In patients with a perfusing rhythm who are receiving amiodarone, if hypotension develops or worsens, slow the rate of the infusion
- Nausea and bradycardia have also been reported
- QT interval prolongation has also been reported; QTc values greater than 500 ms may provoke torsades de pointes
Overdose
Accidental overdose of intravenous amiodarone is likely to produce hypotension, bradycardia, or cardiogenic shock. These should be managed by stopping or slowing the intravenous administration and providing volume replacement. Transcutaneous pacing may be required.
Warning And Precautions
Amiodarone is toxic to tissues if extravasation occurs.
Drug Interactions
Amiodarone may enhance or potentiate the effects of beta blockers, calcium channel blockers, or digoxin and should be used with caution in these patients.