Z-Pacs deemed suspect by Food and Drug Administration officials

The Food and Drug Administration (FDA) has issued a new warning about the popular antibiotic azithromycin which is sold under brands that include Zithromax and Zmax.

According to new studies, the antibiotic may cause abnormal changes in the electrical activity of the heart that may lead to a potentially fatal irregular heart rhythm.

Patients who are at a higher 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.

Drug labels warnings have been updated which strengthens the warnings and precautions section with information related to the risk of QT interval prolongation and “torsades de pointes,” a specific, rare heart rhythm abnormality. Information has also been added regarding the results of a clinical QT study which showed that azithromycin can prolong the QT interval.

Health care professionals are urged to consider the new warning when prescribing azithromycin to patients who are at a higher risk for developing cardiovascular problems.

The FDA released a statement on May 17, 2012, about a New England Journal of Medicine (NEJM) study that compared the risks of cardiovascular death in patients who were treated with the antibacterial drugs azithromycin, amoxicillin, ciprofloxacin (Cipro), levofloxacin (Levaquin), or no antibacterial drug at all. The study reported an increase in cardiovascular deaths in people who were treated with a five-day course of azithromycin compared to persons treated with amoxicillin, ciprofloxacin, or no drug. Furthermore, the study also indicated that the risks of cardiovascular death associated with levofloxacin treatment were similar to those associated with azithromycin treatment.

Director of Pharmacy at Sidney Regional Medical Center, Rachel Forster, says, “In my professional opinion, the information in the news relating to cardiac issues associated with the use of azithromycin (Zithromax) is not overly concerning but certainly worthy of discussion with a healthcare provider. Azithromycin is an important and effective antibiotic within the class of antibiotics known as macrolides. Cardiac side effects have been published in drug literature for macrolide antibiotics for several years. It should be noted that when new drugs are studied prior to FDA approval, testing is conducted on normal, healthy volunteers. As a result, when drugs are approved for use in the general population, side effects and drug interactions not observed in studies in normal, healthy volunteers are more likely to occur in patients with health conditions typically seen in the general population such as congestive heart failure, chronic obstructive pulmonary disease, diabetes, hypertension, etc. The recent information actually highlights the importance of the patient - doctor and patient - pharmacist relationships. A provider with knowledge of a patient’s health history and current medications will prescribe medications best suited for a patient’s acute and chronic health conditions. It is important for patients to discuss with their provider their health conditions and all medications they are taking, including over-the-counter medications, herbals and supplements. With this information, their doctor will be able to prescribe the most appropriate medication(s) for their condition(s). It is also important for patients to fill all their prescriptions at the same pharmacy so their pharmacist can monitor for drug-drug interactions.”