On March 12, 2013, the U.S. Food and Drug Administration (FDA) issued a warning that the antibiotic azithromycin (ZithromaxÂ® or Zmaxâ„¢) can lead to a potentially fatal irregular heart beat. According to the FDA, patients with existing QT interval prolongation, low levels of potassium or magnesium, or a slower than normal heart rate are at particular risk, as are those using certain drugs to treat arrhythmias.
Understanding the risk v. benefit is something that is very important, and should not frighten people from appropriate use of antibiotics. From the original article in the New England Journal of Medicine the risk to people taking azithromycin of cardiovascular death appears to be relatively low – 1 in 11,655* (odds of dying from: heart disease 1 in 5, cancer 1 in 7, motor vehicle accident 1 in 100, assault by firearm 1 in 325, drowning 1 in 8,942, air travel incident 1 in 20,000, tornado 1 in 60,000).
* During matched 5-day intervals among persons who did not take antibiotics, there were 41 cardiovascular deaths (29.8 per 1 million periods), and for those taking 5-day course of azithromycin (hazard ratio=2.88 > 85.8 per 1 million periods = 1 in 11,655).
Groups at higher risk include:
- Patients with known prolongation of the QT interval (1 in 10,000 individuals), a history of torsades de pointes, congenital long QT syndrome, bradyarrhythmias, or uncompensated heart failure
- Patients on drugs known to prolong the QT interval
- Patients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia, and in patients receiving Class IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents.
Elderly patients and patients with cardiac disease may be more susceptible to the effects of arrhythmogenic drugs on the QT interval.
The FDA-approved indications for azithromycin include:
- Acute bacterial exacerbations of chronic pulmonary disease
- Acute bacterial sinusitis (possible use in dentistry)
- Community-acquired pneumonia
- Uncomplicated skin and skin structure infections (possible use in dentistry)
- Urethritis and cervicitis
- Genital ulcer disease
Azithromycin (Z-Pak) is useful in the treatment ofÂ acute bacterial sinusitis for tooth pain caused by the sinusitis (not the tooth). Z-Pak (2-250 mg azithromycin tabs day one, 1-250 mg tab the following 4 days) is effective for a number of reasons: limited doses per day* (compared to 10-day, 3 times a day Augmentin