Zithromax (Z-Pak) Antibiotic Investigation

Stueve Siegel Hanson is investigating the commonly prescribed antibiotic azithromycin -- better known as Zithromax or the Z-Pak.  The FDA has just recently warned patients and doctors concerning an increased risk of cardiovascular incidents caused by this medication.

Zithromax is prescribed to treat bacterial infections including:

  • Chronic pulmonary disease;
  • Sinusitis;
  • Community-acquired pneumonia;
  • Pharyngitis and tonsillitis;
  • Uncomplicated skin infections;
  • Urethritis and cervicitis; and
  • Genital ulcer disease.

Zithromax is often prescribed instead of amoxicillin, because Zithromax is easier to take than the full course of amoxicillin.  Zithromax is a five day course of treatment rather than the ten day course of treatment that is typical for other antibiotics. People believe that they will feel better faster and are often willing to pay a little extra for a prescription that will allow them to do that.

Zithromax (azithromycin) was first approved in the U.S. by the FDA in 1991.  Global sales for Zithromax last year were $1.8 billion, and more than 55 million prescriptions were written in the United States for sales of over $464 million.

The antibiotic is part of a class of antibacterial medications known as macrolides, which have been known to cause abnormal heart rhythm problems and Zithromax may increase the risk of fatal heart problems compared to other antibiotics.

FDA Warning

The FDA warning was prompted by review of two studies that assessed the potential for Zithromax to cause abnormal changes in the electrical activity of the heart. One study, published in the New England Journal of Medicine in May 2012, reported a higher risk of cardiovascular deaths and deaths from any cause in persons treated with a 5-day course of Zithromax compared to those treated with amoxicillin. The estimated excess risk of cardiovascular death compared with amoxicillin ranged from roughly 1 in 111,000 among healthier patients to 1 in 4,100 among those with certain cardiovascular risk factors.

The FDA also reviewed a second study that assessed the potential for Zithromax to cause abnormal changes in the electrical activity of the heart. That study determined that Zithromax can lead to a potentially fatal heart rhythm known as prolonged QT interval, in which the timing of the heart’s contractions becomes irregular.

The FDA said in its Safety Communication that the Warning and Precautions Section of the Zithromax label would be updated with stronger language regarding the risk of life-threatening irregular heart rhythms. The agency also noted that certain risk factors may increase the likelihood an individual will suffer a heart rhythm disturbance while using Zithromax, including:

  • QT interval prolongation - Prolonged time between heart beats when the electrical charge in the heart muscle is recovering
  • Low blood levels of potassium or magnesium
  • Slower than normal heart rate
  • Use of certain drugs used to treat abnormal heart rhythms, or arrhythmias

People with underlying heart problems seem to be especially vulnerable to developing this condition, CNN reported from an interview with Wayne Ray, professor of preventive medicine at Vanderbilt and the study's lead researcher.

"The FDA said patients who have low blood levels of potassium or magnesium are at a higher risk," according to the report. "Patients who have a slower than normal heart rate or are already taking drugs to treat arrhythmias should also be cautious.

The FDA instructed health care professionals to be cautious about prescribing the antibiotic to patients known to have this condition or who have certain risk factors.

Accordingly, it is important for all patients, but most particularly those with heart related ailments, to speak with their doctors about whether Pfizer’s Zithromax drug is the best course of treatment or whether another treatment plan may be more appropriate. If you are taking this drug you should NOT stop taking it simply because of this action by the FDA. Rather, consult with your health care provider and seek his or her advice.  Be sure to seek immediate care if you experience an irregular heartbeat, shortness of breath, dizziness, or fainting while taking azithromycin.

If you or someone you know has experienced serious side effects including heart attack or sudden heart death caused by the antibiotic Zithromax or the Z-Pak and wish to receive additional information about your legal options, please call 1-888-756-6494 or fill out the form on this page.

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