Amiodarone is a prescription drug used to treat life-threatening heart problems. It is given in a tablet form, and can also be administered intravenously by a healthcare professional.

Amiodarone is also known as its brand name, Pacerone. It is part of a class of drugs known as antiarrhythmics.

How Does Amiodarone Work?

Amiodarone’s purpose is to prevent abnormal heartbeats. It does this by controlling muscle contractions in the heart, working on a cellular level, says Healthline.

Very Well Health says that the drug is in two categories of antiarrythmic drugs, because it acts both as a beta blocker and a calcium blocker, dilating blood vessels and blocking the thyroid hormone. 

Very Well Health says that Amiodarone is the strongest and most effective antiarrhymic drug that has ever been developed.

How Does Amiodarone Differ From Other Cardiac Drugs?

Very Well Health goes on to explain that amiodarone is different from other cardiac drugs because it is stored in the body’s tissues rather than the blood stream. According to Very Well Health, the drug is not fully effective in regulating heart rate until a patient’s tissues are saturated it.

When amiodarone is taken by tablet, a patient must often take a high dose for the first week or so to saturate tissues and launch the drug’s effects. The dose can then be lowered over the long-term. 

Very Well Health says amiodarone can be administered intravenously in patients who need immediate heart beat regulation. Delivering the drug intravenously allows a patient’s tissues to become saturated more quickly.

What are Amiodarone Side Effects?

Since the drug is stored in the body’s tissues, it may produce side effects in many of the body’s organs. Amiodarone is slow-acting, so its side effects may take a similarly extended period of time to develop — perhaps months or even years.

Because the drug works as a thyroid blocker, it may cause thyroid problems, including hypothyroidism and hyperthyroidism, low and high thyroid, respectively. Very Well Health says that thyroid problems are a common side effect of the drug, and cautions they can be difficult to identify and treat.

The drug can also cause liver and lung toxicity. Lung toxicity is reportedly a very serious condition, and can be fatal. Like thyroid problems, lung toxicity connected to amiodarone use may be challenging to identify and treat.

Very Well Health goes on to explain that that amiodarone can cause skin problems, including sensitivity to sunlight and a likelihood of developing sun burns. Additionally, the drug may also cause skin to develop a blue-grey discoloration, usually in areas exposed to the sun.

The drug may also affect eyesight by causing deposits to form on the corneas. This may cause a person to develop “halo vision,” a term used to describe a visual fog when looking at bright lights.

MedlinePlus notes that amiodarone side effects may include a worsening of an arrhythmia (irregular heart beat), though this is the condition that that drug aims to treat. It may also cause a new arrhythmia to develop. 

Web MD says some less severe side effects have been associated with amiodarone, including shaking, fatigue, nausea, vomiting, constipation, or loss of appetite. These may be a sign of a more serious complication.