May 22, 2023

Dear colleagues:

Welcome back to our Pharmacy Phriday continuing education offering. In this installment, we will continue to focus on some of the antiarrhythmic medications we find in our drug boxes. 

This week we focus on Amiodarone, our primary choice of an antiarrhythmic in cases of ventricular dysrhythmias.  Amiodarone is a class III antiarrhythmic, which means it decreases the movement of potassium in the heart tissues, slowing the repolarization phase. Amiodarone will also decrease sinus automaticity and increase the refractory period within the AV node. The medication also demonstrates electrophysiological effects of class I, II, and IV antiarrhythmics, essentially meaning everything is slowed down in the heart’s electrical system.  

Amiodarone has been shown to improve the return of spontaneous circulation (ROSC) with refractory V-Fib and pulseless v-tach and is therefore used in our protocols for those rhythms.  It can also be found in the protocol for use in cases of V-tach with a pulse after a 12 lead has been acquired and transmitted to the hospital for possible consultation with medical direction. 

Because of the medication’s action on the sinus and AV nodes, it should not be used in cases of bradycardia, sick sinus syndromes, and second or third-degree AV blocks.  Amiodarone should also not be used in conjunction with other antiarrhythmics or other medications that prolong the QT interval. Remember, it is very important that we only give ONE antiarrhythmic during treatment for cardiac arrest.  It is also important to note that Amiodarone is one of the few medications in our drug boxes that is a “Category X” and should not be used in pregnant females or those breastfeeding (Lidocaine would be the alternative in these cases).

The initial dose of Amiodarone during an arrest for an adult is 300mg IV/IO, followed by 150mg IV/IO in 3-5 minutes if there is no change.  The maximum dose should not exceed 450 mg.  In the case of a wide complex tachycardia with a pulse, the dosage is 150 mg diluted in 100 ml of D5 and administered over 10 minutes.

In the pediatric arrest patient, the dosing is 5 mg/kg, up to three total doses or a max dose of 300mg.  For patients with a pulse, the dose would be 2.5 mg/kg (up to a max of 150 mg), mixed in 100 ml of D5, and administered very slowly over 20-60 minutes.

Side effects associated with Amiodarone result from slowed repolarization, automaticity, and other effects mentioned and can include prolonged PR, QRS, and QT intervals on the ECG, arrythmias that result from those abnormalities, and hypotension.  As always, be sure to monitor your patient.

Next week is National EMS Week, running from May 21st through the 27th.  Look for special events within your local systems as we honor your work in EMS!  Thanks for all you do and the differences you make!

Until the next installment, stay safe!

Sincerely,



The UH EMS-I Team

University Hospitals