Is Amoxicillin Safe If You Have Atrial Fibrillation (A-Fib)?

Answer

While amoxicillin has been rarely linked to causing changes to heart rhythm in case reports, it is generally considered among the safer antibiotic choices if you have been diagnosed with atrial fibrillation.

Other antibiotic classes are considered far more dangerous in those with atrial fibrillation and should be avoided unless you and your doctor determine they represent the best option for you.

What Antibiotics Need To Be Used Cautiously If You Have A Fib?

Several studies have strongly linked two classes of antibiotics with causing potentially dangerous changes to heart rhythm, such as QT-prolongation:

• Macrolides
• Fluoroquinolones

Macrolides include:

• Azithromycin
• Erythromycin
• Clarithromycin

Fluoroquinolones include:

• Ciprofloxacin
• Moxifloxacin
• Levofloxacin
• Ofloxacin
• Gatifloxacin

The FDA (Food and Drug Administration) has released warnings about many of these drugs. For example, in 2013 and 2021, the FDA warned of the risk of QT interval prolongation and potentially fatal 'torsades de pointes' in individuals taking azithromycin:

"The U.S. Food and Drug Administration (FDA) is warning the public that azithromycin (Zithromax or Zmax) can cause abnormal changes in the electrical activity of the heart that may lead to a potentially fatal irregular heart rhythm. Patients at particular risk for developing this condition include those with known risk factors such as existing QT interval prolongation, low blood levels of potassium or magnesium, a slower than normal heart rate, or use of certain drugs used to treat abnormal heart rhythms, or arrhythmias."

All macrolides have been associated with QT interval prolongation and the FDA has released similar warnings for other macrolides, like clarithromycin.

Similar to the warnings for macrolides, caution is also recommended with fluoroquinolone antibiotics in those with certain heart conditions.

As a general rule of thumb, when there are alternative antibiotics available, fluoroquinolones and macrolides are avoided in those with risk factors for arrhythmias, and that would absolutely include if you have been diagnosed with atrial fibrillation. Amoxicillin is often the safer choice.

As mentioned, there are some case reports of amoxicillin causing heart rhythm changes, but it seems quite rare. The FDA has never released a warning about amoxicillin in regard to heart rhythm changes and the vast majority of studies that have found problems with other antibiotics compared those antibiotics to amoxicillin or amoxicillin-type drugs (like this study).

Final Words

So, overall, amoxicillin would generally be seen as the safer choice for someone like you, but of course, there are always other factors that could come into play, like what you are treating, other medical conditions you have, etc...

Be sure to talk to your doctor about any questions or concerns you have.

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