Everything you Need to know about the Z-Pack Medication


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Zithromax (azithromycin), also known as Z-Pak, is an antibiotic approved for treatment of respiratory, skin and other bacterial infections. Studies link the drug to side effects, including an increased risk of fatal heart problems. In August 2018, the U.S. Food and Drug Administration warned of an increased risk of cancer relapse and death in some patients who take the drug long-term.

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Zithromax has been highly profitable for its manufacturer, Pfizer. At the height of sales in 2002, it brought in over $1 billion for Pfizer. Although the wide availability of generics reduced the company’s revenue, sales still totaled $435 million in 2012.

This antibiotic is popular because it treats infections in adults and children. But, the drug is not without side effects — including fatal heart-related risks.

Zithromax also led to some legal trouble for Pfizer. The company was forced to pay millions to several states to settle allegations that it used misleading tactics to market the drug to children.

How Zithromax Works

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Zithromax belongs to a class of antibiotics called macrolides, which are bacteriostatic — meaning they treat infections by preventing bacteria from multiplying and producing the proteins that are essential for their growth. Eventually, the remaining bacteria die or are killed by the immune system, not by the drug itself. This is in contrast to bactericidal antibiotics, which kill bacteria. Bactericidal drugs include fluoroquinolones and penicillin.

Zithromax does not break down in the body as quickly as other antibiotics. Instead of floating freely in the blood, the drug molecules are picked up by white blood cells that fight bacteria. The white blood cells take the medicine to the front lines of their struggle with germs, where it becomes concentrated in the tissues surrounding the infection. That concentration helps it remain in the body longer, which means patients need fewer doses to beat their infections.

Zithromax and Z-Pak Dosage

Zithromax is most familiar to the public as the “Z-Pak,” a convenient five-day pill regimen with a dose of 500 mg (2 tablets of 250 mg) the first day and 250 mg for the remaining four days. But, Zithromax comes in several dosages and forms, including oral tablets and liquids for oral use, injections and intravenous drips.

Who Shouldn’t Take Zithromax?

According to the medication insert, certain people should not take Zithromax. Patients with allergies to azithromycin, erythromycin, or any macrolide or ketolide should not take Zithromax. People with liver problems or who had jaundice with prior use of Zithromax should not take it again.

Side Effects

In most cases, patients don’t experience side effects from Z-Paks. In clinical trials, adverse reactions occurred in about 12 percent of patients, and less than 10 percent of the reactions were severe.

The most common side effects were gastrointestinal and included diarrhea, stomach pain and nausea. Generally, side effects were more severe with a higher dose.

Serious side effects are rare but can be life-threatening. These include severe allergic reactions, liver injury and diarrhea associated with antibiotic-resistant bacteria. In March 2013, the FDA warned azithromycin, including brand names Zithromax, Zmax, Azithrocin and Azin, “can cause abnormal changes in the electrical activity of the heart that may lead to a potentially fatal irregular heart rhythm.”

More recently, in August 2018, the FDA warned long-term use of Zithromax can cause cancer relapse and death in people who have had blood or lymph node cancer and have received donor stem cell transplants.

Read all this information before taking Z-pak medication.

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