Article

Amiodarone (Nexterone, Pacerone)
January 30, 201904,025

What is Amiodarone?

Amiodarone is a drug used to treat arrhythmias (irregular heartbeats).1

It is sold under brand names Cordarone, Pacerone, and Nexterone.5,6 CoAmiodarone is approved by the FDA to treatradarone and Pacerone are pills. Nexterone is a sterile liquid that can be given as an IV.5,6

Amiodarone is a prescription drug. You can only buy it with a valid order from your doctor.5,6  

How Does Amiodarone Work?

Like most antiarrhythmic drugs (drugs that treat irregular heartbeats), amiodarone works by changing how electrical signals move through your heart.1,4

Amiodarone alters the electric signals in your heart by blocking special channels in your heart cells. These channels allow sodium, potassium, and calcium to move in and out of your cells.2,8

Sodium, potassium, and calcium are what carry the electrical signal through your heart. By blocking the channels that let these elements move through your cells, amiodarone changes the electrical signals. This, in turn, changes how your heart beats.2,8

Since amiodarone blocks all three kinds of channels in your heart cells, it has multiple effects on your heartbeat. It is able to2,7:

    • Slow down the squeezing motion of your heart during each heartbeat
    • Increase the time between your heart beats
  • Slow down your heart rate

At rest, calcium and sodium are kept out of heart muscle cells, while potassium is kept inside (top). When a heartbeat occurs, sodium enters the cell. This allows channels to open that let calcium into the cell and potassium out. Calcium activates the muscle in the heart to contract (middle).

When amiodarone is present, it sticks to the channels for sodium, potassium and calcium. This slows down how fast the sodium, calcium and potassium can move in and out of your cells, slowing down your heartbeat. (original diagram; see source 18 for more information).

Amiodarone Usage

FDA Approved Uses

Amiodarone is approved by the FDA to treat a specific type of irregular heartbeat called ventricular fibrillation (V-Fib).2

V-Fib occurs when an abnormal heartbeat happens in the part of your heart called the ventricles. These are the larger chambers of your heart that pump blood from your heart to your lungs and body.19

V-Fib is a serious condition that can cause your heart to stop beating.19

Off-label Uses

Though not approved by the FDA, doctors also prescribe amiodarone for a type of arrhythmia called atrial fibrillation (A-Fib).2

A-Fib occurs when an abnormal heartbeat happens in the part of your heart called the atria. These are the smaller chambers of your heart that pump blood into your ventricles.20

A-Fib can cause blood to pool in your heart, creating blood clots. This puts you at risk for a heart attack or stroke.20

Location of the ventricles (involved in V-Fib) and atria (involved in A-Fib) are highlighted.

Modified from iStockphoto/Jack0m.

Amiodarone Dosage

Adult Dosage

The dosage of amiodarone your doctor prescribes for you will depend on 2,6:

    • if you are taking it as a pill or IV
  • if you are taking it to treat V-Fib or A-Fib
Amiodarone Pills/Tablets

Doctors usually prescribe amiodarone in pill form.2

You should take the prescribed dosage at the same time every day. You should also decide at the beginning of your treatment if you want to take amiodarone with or without food. You should then do so for the rest of your therapy.

Typical therapy begins with an initial large dose followed by smaller “maintenance” doses.2

If your doctor prescribes amiodarone for you to treat V-Fib, you will likely be given2:

    • starting dose:  800 mg – 1,600 mg per day until you have taken a total of 10,000 mg (usually 1 week to 12 days)
  • maintenance doses: 200 – 400 mg per day

If your doctor prescribes amiodarone to treat A-Fib, you will likely be given2:

    • starting dose: 600 – 800 mg per day until you have taken a total of 10,000 mg (usually 12 to 16 days)
  • maintenance doses: 200 mg per day
Amiodarone IV

Doctors generally only give amiodarone as an IV in emergencies. It is difficult to say exactly which dose of amiodarone may be necessary for you in an emergency situation. Your doctor will determine how much of this drug you may need.2

Typically, however, IV dosage of amiodarone in an emergency situation is6:

    • starting dose: 150 mg over 10 min
    • maintenance dose (phase I): 1 mg per minute for 6 hours
  • maintenance dose (phase II): 0.5 mg per minute for the next 17 to 18 hours
Dosage for Older Adults

If you are an older adult, your therapy with amiodarone will likely be similar to therapy used for younger adults.11

However, since elderly individuals are at greater risk for side effects, your doctor will likely prescribe a starting dose at the low end of the normal range first. This is to see how the drug is going to affect you.11

If needed, your dosage may be increased over time.11

Child Dosage

Doctors prefer not to give amiodarone to children if it can be helped. This is because amiodarone can have serious long-term side effects.6,12,13

If your child has a serious arrhythmia, however, amiodarone may be necessary.6,12,13

In this case, your child’s dosage will be calculated based on his or her weight.6,12,13

 Amiodarone Pills/Tablets

A typical dosage scheme for a child taking amiodarone is13:

      • starting dose: 5 mg per kilogram of body weight twice per day for 10 days
    • maintenance dose: 5 mg per kilogram of body weight once per day

The total daily dosage should not exceed 200 mg.13

Amiodarone IV for Kids

If amiodarone is needed in an emergency situation, your child’s doctor will likely order an IV. 13

A typical IV dosage of amiodarone for children is13:

    • starting dose: 5 mg per kilogram of body weight over 20 min (maximum 300 mg)
  • maintenance dose: 10 mcg per kilogram per minute over the following 24 hours (maximum 1,200 mg)

Amiodarone Side Effects

More Common Side Effects

Amiodarone has several common side effects. These include 2:

    • small deposits of minerals in your eyes (corneal microdeposits)
    • nausea
    • loss of appetite
    • becoming sunburned more easily (photosensitivity)
  • blue discoloration of your skin

While none of these side effects are life-threatening, some of them may become severe enough to impair your quality of life.2

If you start having problems seeing due to the deposits of minerals in your eyes, you should contact your doctor at once. This may need to be addressed and your medication changed.2

If your nausea or loss of appetite become severe, you should speak to your doctor about lowering your dosage.2

Serious Side Effects

Amiodarone may cause some serious side effects as well. These include:

  • Lung damage

This is the most serious side effect of amiodarone. Severe lung damage from amiodarone occurs anywhere from 2 to 17 percent of people who take it.2

Symptoms of developing lung damage are a persistent cough and/or trouble breathing.2

If you experience either of these symptoms while taking amiodarone, contact your doctor immediately. These symptoms could progress very quickly and you may become unable to breathe.2

  • Low Heart Rate and Blood Pressure

In some cases, amiodarone can cause your heart rate to slow down too much. This can cause your blood pressure to drop too low.2

This side effect is most common if amiodarone is given by IV. Your doctor will likely monitor your blood pressure closely while you are on amiodarone in the hospital.6

If you experience severe low blood pressure with amiodarone (either as an IV or pill), your doctor may decide a pacemaker is the safer option for you to regulate your heartbeat.2

  • Liver Damage

Amiodarone can be toxic to your liver. Your doctor will likely order blood tests to measure your liver function every 6 months.6

  • Thyroid Damage

Amiodarone may be toxic to your thyroid as well. Your doctor will likely order blood tests every 6 months to monitor your thyroid function.6

Woman touching her neck

Stopping or Discontinuing Amiodarone

You should not stop taking amiodarone without talking to your doctor.1

Do not stop taking amiodarone because your symptoms have improved. This does not mean your condition has been cured. It simply means the drug is working. If you stop taking amiodarone, your symptoms may return.2,14

Stopping amiodarone can be complicated because it stays in your body for a very long time (several months).1,6 This means it is difficult to predict how and when the levels in your blood will drop off. Your doctor should monitor you closely and help you transition to a new treatment safely.1,6

Warnings for Amiodarone Use

General Warnings

Do not take amiodarone if you are allergic to it or any of its ingredients.2

Do not eat grapefruit or drink grapefruit juice while taking amiodarone. Grapefruits contain a compound that keeps your body from eliminating amiodarone.2 This can cause it to build up in your body and may lead to serious side effects or overdose.6

Take care to take no more amiodarone than prescribed by your doctor. Amiodarone stays in your system for a long time. This makes it difficult to treat an overdose.6

Warnings for Special Groups

Pregnant Women

Tell your doctor if you are pregnant or wish to become pregnant before taking amiodarone.6

Amiodarone is not safe during pregnancy and may harm your unborn baby.6

If you are already taking amiodarone and discover you have become pregnant or decide you wish to become pregnant, talk to your doctor. You may need to stop taking amiodarone.6  

   Nursing Mothers

Amiodarone can get into breast milk.6 You should not take amiodarone while nursing.

If your doctor decides you need to take amiodarone, you should stop nursing.6

   Young Children (Under 3 Years of Age)

Amiodarone has not proven safe or effective in children under 3. It should not be given to them.8,13

Amiodarone Compared to Other Similar Drugs

Amiodarone vs. Digoxin

Digoxin is another drug that can regulate your heartbeat.15

Doctors usually prescribe it to treat heart failure, but it may also be prescribed for A-Fib.15

Digoxin treats A-Fib by slowing down your heart rate in general. This works well for A-Fib symptoms when you are resting. It is not very effective, however, at preventing A-Fib when you are exercising.15

For this reason, your doctor is more likely to prescribe amiodarone than digoxin to treat A-Fib.16

Amiodarone vs. Adenosine

Adenosine is a chemical that your body makes naturally to slow down your heart rate.

Your doctor may give you extra adenosine as a medication you if you are experiencing a serious heart arrhythmia.9

Amiodarone vs. Metoprolol

Metoprolol belongs to a class of drugs called “beta blockers.” It is used to treat A-Fib after heart surgery.17

It is not yet clear if one drug or the other is more effective at treating A-Fib.17

Your doctor will decide whether amiodarone or metoprolol is a better option in your specific case.

Amiodarone vs. Atropine

Both amiodarone and atropine are effective for treating irregular heartbeats. They are used to treat different conditions, however.9

Amiodarone slows down your heartbeat if it is going too quickly.2

Atropine speeds up your heartbeat if it is going to slow or has stopped.9

Amiodarone Drug Interactions

Amiodarone has serious interactions with several other drugs. The most important of these include:

  • Antihistamines

Antihistamines can make it more difficult for your body to get rid of amiodarone. This can cause it to build up in your body, putting you at higher risk for side effects or overdose.6

  • Antidepressants

Antidepressants may make it more difficult for amiodarone to be removed from your body as well.6 Taking amiodarone with an antidepressant may put you at greater risk of side effects or overdose.

  • Blood thinners

Taking amiodarone with blood thinners can increase the effects of the blood thinner. This can put you at risk for serious bleeding.6

  • Opioids

Opioid pain-killers can increase the heart-rate lowering effects of amiodarone.6 Taking opioids with amiodarone can cause your heart rate to slow down too much, putting you at risk of developing extremely low blood pressure.

You should never take opioids while on amiodarone unless your doctor specifically tells you to.6

  • Antibiotics

Some antibiotics can cause your body to eliminate amiodarone more quickly. This can cause levels in your body to drop off, making the drug less effective.6

If you need to take an antibiotic while taking amiodarone, your dose of amiodarone may need to be increased.6

This list does not include all possible drug interactions.6 Other serious interactions may exist. For this reason, it is important to tell your doctor about all drugs, herbal supplements and vitamins you are taking before you are prescribed amiodarone. She may need to adjust your dose or prescribe different drugs for you.6

You should also tell your doctor if you start taking any new drugs or supplements while taking or within the first few months after stopping amiodarone. This will allow her to adjust your dosages as necessary.6

Abuse of Amiodarone

Amiodarone does not cause any psychological effects or “highs”. It is very unlikely to be abused.6

Amiodarone FAQs

  • How fast can you give amiodarone in the middle of a crisis?

Amiodarone can be given immediately in a crisis. In this case, it should be given by IV at a hospital.2

  • Which arrhythmias can amiodarone treat?

Amiodarone is approved by the FDA to treat ventricular fibrillation (V-Fib).2

Doctors also prescribe amiodarone to treat atrial fibrillation (A-Fib). However, the FDA has not approved amiodarone for this use.2

  • What is the half-life of amiodarone? Why is this important to know?

The half-life of amiodarone is about 58 days.2

This is important because it means that amiodarone stays in your body long after you stop taking it.2  

This means that you have to be careful of drug interactions, side effects, and restrictions for pregnancy and nursing for months after stopping amiodarone.6

  • What is the half-life of amiodarone IV?

The half-life of amiodarone taken by IV is 58 days.2,6

  • What is the best time to take amiodarone?

There is not a “best” time to take amiodarone. However, you should take it at the same time every day.2

You should also always take it with or without food.2, 11

Consistency is key to making sure that you have a steady level of amiodarone in your body at all times.2,11

References

  1. Amiodarone. Medlineplus.gov. Last revised March 15, 2017. Available at https://medlineplus.gov/druginfo/meds/a687009.html. Accessed September 5, 2017.
  2. Siddoway LA. Amiodarone: guidelines for use and monitoring. Am Fam Physician 2003 1;68(11):2189-96. Available at http://www.aafp.org/afp/2003/1201/p2189.html. Accessed on September 5, 2017.
  3. Medications for Arrhythmia. Heart.org. Last revised September 2016. Available at http://www.heart.org/HEARTORG/Conditions/Arrhythmia/PreventionTreatmentofArrhythmia/Medications-for-Arrhythmia_UCM_301990_Article.jsp#.Wa8Zp_OGOUk/. Accessed on September 5, 2017.
  4. Antiarrhythmics. Heartandstroke.ca. Available at https://www.heartandstroke.ca/heart/treatments/medications/antiarrythmics. Accessed on September 5, 2017.
  5. Amiodarone (Oral Route) Descriptions and Brand Names. Mayoclinic.org. Last updated March 1, 2017. Available at http://www.mayoclinic.org/drugs-supplements/amiodarone-oral-route/description/drg-20061854. Accessed September 5, 2017.
  6. Nexterone (amiodarone hydrocloride) injection label. Fda.gov. Available at https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/022325s002lbl.pdf. Accessed on September 5, 2017.
  7. Janse MJ. To prolong refractoriness or to delay conduction (or both)? Eur Heart J 1992;13 Suppl F: 14-8. DOI: 10.1093/eurheartj/13.suppl_F.14.
  8. Amiodarone. Nih.gov. Published on September 16, 2004. (last update unknown). Available at https://pubchem.ncbi.nlm.nih.gov/compound/amiodarone. Accessed on September 5, 2017.
  9. Trappe HJ. Concept of the five ‘A’s for treating emergency arrhythmias. J Emerg Trauma Shock. 2010;3(2):129-36. DOI: 10.4103/0974-2700.62111
  10. Goldschlager N, Epstein AE, Naccarelli G, Olshansky B, Singh B. Practical Guidelines for Clinicians Who Treat Patients With Amiodarone. Arch Intern Med. 2000;160:1741-1748. DOI: 10.1001/archinte.160.12.1741

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