Dronedarone for A-Fib: A Non-Toxic Treatment Alternative?

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Dronedarone (Multaq) is an antiarrhythmic drug that was developed for treating atrial fibrillation. In their search for a safe and effective drug for this condition, pharmaceutical companies have long imagined their holy grail: a drug that is as effective as amiodarone, but without its unique toxicity. Dronedarone was developed by Sanofi (the makers of amiodarone) specifically in the hope of creating that holy grail.

Effectiveness

As antiarrhythmic drugs go, dronedarone is reasonably effective in treating atrial fibrillation. Unfortunately, this is not saying very much. Several clinical trials have demonstrated that dronedarone is moderately effective in maintaining a normal rhythm in people who have had atrial fibrillation.

Specifically, dronedarone has been shown to be significantly more effective than placebo. Still, 64% of patients treated with dronedarone had recurrent atrial fibrillation during the first year of treatment. In contrast, 75% of patients who received placebo had recurrent atrial fibrillation. This modest improvement is roughly similar to that seen with most other antiarrhythmic drugs — again, it’s not saying very much.

In a clinical trial comparing the effectiveness of dronedarone to amiodarone, dronedarone proved to be inferior to its “parent” drug. 64% of people with atrial fibrillation treated with dronedarone had recurrent atrial fibrillation at one year, compared to “only” 42% of those treated with amiodarone.

How Well Is Dronedarone Tolerated?

Dronedarone is a derivative of amiodarone, which is the most effective, but most toxic, antiarrhythmic drug yet developed. Unlike amiodarone, dronedarone does not contain iodine atoms. It is believed that the iodine in amiodarone produces some of the drug's striking toxic effects, especially the thyroid toxicity seen with the drug and perhaps the lung toxicity.

And as it turns out, dronedarone has not displayed the broad spectrum of unique toxicities associated with amiodarone. However, liver toxicity has been reported with dronedarone, and some cases of lung toxicity have also been seen. People who have had liver or lung problems on amiodarone should not be given dronedarone.

Studies have suggested that people with heart failure, or who have left ventricular ejection fractions of 35% or below, may have an increased risk of death when taking dronedarone. Dronedarone should not be used in people with these conditions.

The other side effects of dronedarone appear to be relatively benign. The most common reported side effects are diarrhea or nausea, slow heart rate, and rash.

The Bottom Line

Like all antiarrhythmic drugs, dronedarone should be used with caution. Its recommended use is to help maintain a normal heart rhythm in patients who have had episodes of atrial fibrillation. If atrial fibrillation recurs while taking dronedarone, the drug should be stopped, and a different treatment strategy adopted.

The drug is best used in younger people who have only intermittent atrial fibrillation and who have otherwise healthy hearts.

Read more about the treatment of atrial fibrillation.

A Word From Verywell

As it has turned out, dronedarone is not the holy grail. Indeed, the story with this drug is the same story that has been heard many times with antiarrhythmic drugs — initial excitement, followed by ultimate disappointment. As a group, antiarrhythmic drugs are only moderately effective, yet are among the most toxic drugs in medicine. They should be used only after careful consideration of all the alternatives, and when the potential benefits clearly outweigh the very real risks.

View Article Sources
  • Dorian P. Clinical Pharmacology Of Dronedarone: Implications For The Therapy Of Atrial Fibrillation. J Cardiovasc Pharmacol Ther 2010; 15:15S.
  • Hohnloser SH, Crijns HJGM, van Eickels M, et al. Effect of dronedarone on cardiovascular events in atrial fibrillation. N Engl J Med 2009; 360:668-678.
  • Connolly SJ, Camm AJ, Halperin JL, et al. Dronedarone in high-risk permanent atrial fibrillation. N Engl J Med 2011; DOI: 10.1056/NEJMoa1109867.