Amiodarone is just one of those medications that if you take care of patients in any medical capacity, you need to know. It’s one of the standard drugs in the ACLS algorithm and is not just used for acute dysrhythmias, but is also taken chronically by over 1 million Americans nationwide.
Amiodarone is classified as an antiarrhythmic which is a blanket classification as many cardiac dysrhythmia medications have numerous modes of action and cannot be easily classified into one subset. For example, Amiodarone works mainly as a potassium channel blocker but also has some effect on blocking sodium and calcium channels, and even some beta blocking mechanisms.
All these actions together create a longer repolarization phase, essentially slowing the conduction rate and prolonging the refractory period of both the AV/SA nodes, the ventricles, the bundle of His and the perjunke fibers. This can be seen by a prolonged QT interval.
Because of Amiodarone’s prolonging effects, it is a great drug for life threatening tachycardias such as Ventricular tachycardia, Supraventricular tachycardia, wide-complex tachycardia, and ventricular fibrillation.
It is important to note that although Amiodarone is a first line drug, first line treatment of these arrythmias, especially if symptomatic is cardioversion/defibrillation followed by amiodarone if there is no change. An example is that Amiodarone is given following the 3rd unsuccessful shock in v-fib/v-tach. (your protocol may vary).
Dosing for pulseless VT/VF is an initial 300mg push followed by 150mg three minutes later if no conversion. If the patient converts following the last dose, then an infusion dose will be started to prevent reentry. Infusion dosing is typically 1mg/min for 6 hrs then titrating down to 0.5mg/min for 18hrs. If the patient happens to have reentry pulseless tachycardia, all subsequent push doses of Amiodarone will be 150mg. The important thing to note is the maximum cumulative dose of Amio for a 24 hour period is 2.2 grams.
For non-life threatening tachycardias the usual dose is 150mg over 10 minutes with an infusion of 1mg/min for 6 hours and expert consultation ASAP.
Remember all you nurses, medics, corpsman and EMTs this is basic ALS and needs to be a part of your permanent drug therapy memory, if it’s not…time to review asap!