This week, the New England Journal of Medicine (NEJM) published a report from the Vanderbilt University School of Medicine which found a small, previously unrecognized risk from the use of the antibiotic azithromycin (brand name Zithromax, also sold as a “Z-pak”).
Commonly used for respiratory tract infections, azithromycin has become very popular because of its ability to eradicate many infections in five days, as opposed to the 7-10 days needed for most other antibiotics. It also has had a favorable safety and side effect profile.
The concern involves the potential for the medication to induce dangerous, or even lethal cardiac rhythm disturbances. Whereas the drug has been generally thought to be free of such effects, there have been seven published reports and 20 non-published reports of patients who serious rhythm problems.
The authors of the NEJM study looked at data from the Tennessee Medicaid program, and tried to quantify the adverse events, which occurred during antibiotic treatment. They found that a 5 day course of azithromycin was associated with a small increase in the risk of cardiovascular death, which was more pronounced in patients who had underlying cardiac conditions. To put the numbers in perspective, for every million courses of the medication, there were 47 additional deaths; patients with significant heart disease had 245 additional deaths per one million five days courses. The authors looked at antibiotics with no known such risk (amoxicillin and ciprofloxacin) and found that azithromycin was associated a higher risk of death than these. They also looked at an antibiotic with a known risk of cardiac rhythm disturbance (levofloxacin), and found the two medications with equivalent risk.
As always, this kind of report needs to be put in perspective. When indicated, azithromycin is an important medication and can keep you healthy, or even save your life. If used appropriately the risks of the medication are far outweighed by the benefits. However, the key words are “if used appropriately”. As a class, antibiotics are used excessively and inappropriately---for non specific fevers, for syndromes which are clearly viral (and therefore not responsive to antibiotics), and for a wide variety of upper respiratory complaints.
Much of the overuse is generated by patient pressure—many people feel that if a physician visit does not end with a prescription then the visit has been unsatisfying. This should not be interpreted as shifting the blame—in the end the physician needs to practice and prescribe, and to educate their patients on the fact that NO medication is free of side effects, so that if the medication is not indicated, the risks will exceed a benefit of zero.
Active participation in decisions regarding medications which are, or art not, prescribed, is an important responsibility in managing our health.