Amiodarone

Amiodarone is a medication that we use quite frequently in the ICU. Most of the time it works rather quickly and is our drug of choice when it comes to certain types of heart arrhythmias (meaning abnormal heart rhythms).

Medication Classification

Amiodarone is classified as an antiarrhythmic drug, meaning that it is used on patients who have heart arrhythmias especially atrial flutter, atrial fibrillation, and tachyarrhythmias.

[Amiodarone is a] class III antiarrhythmic agent, which inhibits adrenergic stimulation; affects sodium, potassium, and calcium channels; markedly prolongs action potential and repolarization; decreases AV conduction and sinus node function.
— Medscape

The most common arrhythmia that we use this medication on in the ICU is atrial fibrillation.  It is also used to treat many ventricular arrhythmias as well. It works directly on cardiac tissue and helps to slow down the nerve impulses that are causing the arrhythmia.  

Administration 

Make sure to administer amioidarone according to your provider's prescription.  It seems that most commonly patients are given a 300 mg bolus of amiodarone initially and then given a continuous drip.  They are started at 1 mg/min for 6 hours, and then moved down to 0.5 mg/min for 18 hours.  

Nursing Tip:  I usually just set the IV pump for a volume equivalent to 6 hours worth of medication administration.  Then when the pump alarms, I know to turn down my rate to 0.5 mg/min. I then set it for a volume equivalent to 18 additional hours so that the pump alarms and the next nurse knows the 18 hours is up. 

After the full 24 hour regimen is completed, the doctor assesses the patient to see if a longer continuous drip is needed.  They may also bridge the patient over to an oral antiarrhythmic drug to control their heart rhythm.  Do not administer amiodarone if the patient's heart rate is low, as the amiodarone will slow the heart beat further.  You may also see a drop in the patient's blood pressure, so be looking for that!  

Pharmacokinetics

I thought this information was pretty interesting.  I'm always curious to see how quickly drugs work on my patients and how they eventually get rid of them. Check out some of the drug information from Medscape:

Absorption

  • Bioavailability: 35-65%
  • Onset (PO): Initial response 2 days to 3 wk; peak response takes 1 week to 5 months
  • Duration (PO): Up to 50 days after discontinuation of therapy
  • Peak serum time: 3-7 hr (PO)
  • Therapeutic range: 0.8-2.8 mcg/mL
  • Toxicity range: >2-2.5 mcg/mL

Elimination

  • Half-life: 26-107 days (parent drug); 61 days (DEA metabolite)
  • Dialyzable: Not dialyzable by hemodialysis or peritoneal dialysis
  • Excretion: Feces; urine

Other relevant articles include:

References

Mayo Clinic

Medscape

Posted
AuthorCourtney Tracy