Zithromax (azithromycin) is an antibiotic used to treat a wide variety of infections. It is most commonly prescribed as a Z-Pak and may be given for only a few days. Zithromax is one of the most popular antibiotics in use for both children and adults, but it may cause serious complications including potentially fatal cardiac or heart side effects. Drug manufacturer, Pfizer, has faced thousands of Zithromax lawsuits filed by patients or loved ones of those who were injured by Zithromax or Z-Pak use.

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What is Zithromax?

Zithromax (azithromycin) is a powerful antibiotic manufactured by pharmaceutical giant Pfizer.  Zithromax is designed to travel deep into the body’s infected tissue and release slowly over time. In some cases, Zithromax can be taken for as little as one day, as opposed to other antibiotics which often require a week or longer. Zithromax is commonly given as a “Z-pack” which contains 5 days’ worth of medication.

Zithromax was first approved in 1991 and in 2001, use was expanded to include a single-dose or three-day treatment for acute otitis media or ear infection in children. It has since become one of the most widely-used antibiotics in the U.S. and is given for a range of illnesses caused by bacterial infection. At its peak, Zithromax brought about $2 billion in annual revenue to Pfizer but even several years after patent loss, the medication still makes about $300 million for the company each year.

While Zithromax has provided adult and pediatric patients with fast infection relief, it has also caused serious side effects. The FDA issued a warning explaining the increased risk of fatal heart conditions from Zithromax use and thousands of people of loved ones of those who used Zithromax and experienced serious side effects have filed Zithromax lawsuits against Pfizer.

Zithromax Uses

Azithromycin belongs to a medication class called macrolide antibiotics. Azithromycin is designed to stop bacterial growth within the body. It can be used to treat several bacterial infections, but is not used for flu, colds, or other viral infections.

Zithromax comes in tablet and liquid forms and can be used to treat several types of infections in adults and certain infections in children. The drug is FDA-approved to treat pediatric ear infections, pneumonia, and throat infections such as strep throat.

Zithromax can be used to treat adult conditions such as:

  • Sinus infections
  • Ear infections
  • Skin infections
  • Gastrointestinal infections such as traveler’s diarrhea
  • Throat infections such as strep throat and tonsillitis
  • Lung infections such as pneumonia and bronchitis
  • Sexually transmitted infections such as gonorrhea

Sexually Transmitted Infections (STIs)

Zithromax can also be used to treat certain types of sexually transmitted infections (STIs). Sexually transmitted infections are a group of infections transmitted most frequently through sexual contact. These infections are often mistakenly referred to as sexually transmitted diseases (STDs). Zithromax can be used to treat STIs such as gonorrhea, chlamydia, and chancroid.

Pediatric Zithromax Use

In 2001, the FDA approved Zithromax use in children’s ear infections, or acute otitis media. Children with ear infections may receive Zithromax as a single-dose or on a three-day treatment regimen. Acute otitis media is an infection of the middle ear, which is located behind the eardrum. Unlike many other liquid medications, Zithromax for children should not be kept in the refrigerator.

Zithromax Side Effects

Like any prescription medication, Zithromax may cause a number of side effects. These side effects usually range from mild to moderate but in some cases, may be severe, serious or even life-threatening.

Common side effects associated with Zithromax use include:

  • Diarrhea
  • Nausea
  • Abdominal pain
  • Vomiting
  • Nervousness
  • Dermatologic reactions

Though not common, in some cases Zithromax may cause rare but serious side effects which warrant medical attention. These side effects may include:

  • Stevens Johnson Syndrome – a severe and potentially life-threatening skin condition which appears as a “bulls-eye” rash
  • Liver function impairment
  • Allergic reaction including anaphylaxis
  • Diarrhea associated with antibiotic use

Zithromax users should seek immediate medical attention at the onset of the following side effects:

  • Seizures
  • Fainting
  • Bleeding gums
  • Flu-like symptoms
  • Severe diarrhea
  • Black, tarry, or bloody stool
  • Dark-colored urine
  • Blurred vision
  • Unusual bruising or bleeding
  • Peeling, loosening, or blistering of the skin
  • Unusual weight changes
  • Changes in hearing
  • Jaundice, or yellowing of the eyes and skin
  • Irregular or decreased heart rate

Zithromax Heart Risk

In May 2012, the New England Journal of Medicine conducted a study on the safety of Zithromax versus other types of antibiotics. Included in this study was amoxicillin, another popular antibiotic prescribed to treat common bacterial infections. The study found that patients who took Zithromax had a higher risk of developing fatal heart rhythms.

The study found that Zithromax use may alter the heart’s natural electrical activity which may lead to a potentially fatal condition known as prolonged QT interval. During prolonged QT interval, the heart’s contraction timing becomes irregular.

This study compared several antibiotics, including azithromycin, amoxicillin, levofloxacin, and ciprofloxacin. Also compared was treatment with no antibiotic drug. The study showed that patients treated with a five-day azithromycin cycle showed a higher risk of cardiovascular death than those treated with ciprofloxacin, amoxicillin, or no antibiotic. In healthy patients, the risk of cardiovascular death was one in 111,000. In high-risk patients, the risk drastically increased to one in 4,100.

Zithromax Cardiac Risk Factors

Risk factors for Zithromax arrhythmia include preexisting heart conditions. Patients with low blood potassium or magnesium levels are at-risk for Zithromax heart problems. Patients are also at-risk if they have a heart rate that is slower than normal. Those who use certain medications to treat abnormal heart rhythms may also experience Zithromax heart problems.

QT Interval Prolongation

QT interval prolongation is a disorder of the heart’s electrical cycle. The QT interval is the time duration between the start of the heart’s Q wave and the end of its T wave. Essentially, the QT interval measures the depolarization and repolarization that takes place in the heart’s ventricles. QT interval prolongation is associated with decreased heart rate. These prolonged QT intervals can typically be detected using diagnostic machines such as electrocardiogram (ECG).

Torsades de Pointes

Torsades de pointes is a rare and specific type of heart problem that results in ventricular tachycardia, or increased heart rate. This condition is associated with QT interval prolongation. Torsades de pointes translates from French to “twisting of the spikes.” Torsades de pointes is associated with a sharp decrease in the patient’s arterial blood pressure. This can cause syncope, or fainting.

In some cases, Torsades de pointes can degenerate into a condition called ventricular fibrillation. Ventricular fibrillation results in uncoordinated contractions in the ventricular muscles. This can then lead to cardiogenic shock and a lack of proper blood circulation. If the patient does not receive immediate medical attention, sudden death can occur.

Zithromax FDA Warning

In March 2013, the FDA issued a safety warning for Zithromax, based on information published by the New England Journal of Medicine. The warning stated that Zithromax was found to cause irregular heart rhythms in patients, a condition which could prove fatal for certain patients. The FDA warning urges doctors to take caution when prescribing Zithromax. Patients who are currently at-risk for heart complications should be prescribed other types of antibiotics for the sake of safety.

Zithromax Warning Label

As part of the 2013 warning, Zithromax manufacturer Pfizer added Zithromax heart problems to the drug’s Warning and Precautions label section. The label now includes the risk of developing QT interval prolongation and Torsades the pointes. The label also includes information from a clinical study which reveals that azithromycin can prolong a patient’s QTc inverval, or corrected QT interval.

Azithromycin Precautions

The FDA cautions health care professionals to take certain considerations before prescribing Zithromax and other drugs that can cause heart problems. Special consideration should be given to patients who exhibit preexisting risk for cardiovascular events. Other drugs in the macrolide drug class may increase heart problem risks. Additionally, non-macrolide drugs such as fluoroquinolones are also known to cause heart problems in high-risk patients.

In 2013, the FDA stated that Zithromax use could lead to abnormal changes in the heart’s electrical activity. These changes could potentially cause a patient to have an irregular heart rhythm that could lead to death. Earlier in 2012 the FDA had also noted that Zithromax could increase the risk of death in patients, particularly those with previous heart conditions.

Specifically, the FDA reported that those with the following preexisting conditions are at a particular risk of irregular heart rhythm or death:

  • QT interval prolongation
  • Low blood levels of magnesium
  • Low blood levels of potassium
  • Slower than normal heart rate
  • Specific drugs to treat abnormal heart rhythms or arrhythmias
  • Experience Torsades de pointes, a heart rhythm abnormality

Lawsuits against Pfizer

Zithromax side effects are also the subject of numerous class action lawsuit investigations against Pfizer in the wake of the FDA’s statements. These lawsuits focus on QT interval prolongation and Torsades de pointes (TdP) as potentially fatal Zithromax side effects. Some attorneys claim these Zithromax side effects were not adequately investigated by Pfizer before the drug was out on the market. Attorneys filing these class action lawsuits are looking for individuals or family members who have experienced loss or personal injury due to life-threatening Zithromax side effects.

Zithromax Dosage and Instructions

Zithromax comes in tablet form, as 250 mg, 500 mg, and 600 mg tablets. It also comes in powder for oral suspension with dosage of 100 mg per 5 mL, 200 mg per mL. In extreme cases of pneumonia or pelvic inflammatory disease, the first dose may be given by injection.

Prescription dosages may vary by case according to disease type, age of the patient and other factors to be determined the doctor. Patients are warned to always complete their full Z-Pak and to never take double doses, even if a dose of Zithromax is missed.

Zithromax Lawsuits

Pfizer, Zithromax’s manufacturer, was sued by 19 states who claimed that the company misrepresented the effectiveness of Zithromax and minimized or failed to disclose risks of the medication. Pfizer was roundly criticized for the use of a zebra “mascot” known as “Max”, which was included in promotional materials such as plastic zebras and zebra-striped documents. The company reportedly also donated a zebra named Max to the San Francisco zoo as part of the marketing campaign.

Pfizer has faced a number of Zithromax lawsuits filed by patients or family members of those who took and were injured by Zithromax. None of these lawsuits have been to trial or have resulted in settlements.

Notwithstanding claims relating to this product, the drug/medical device remains approved by the U.S. FDA.