Key takeaways:
A Z-Pak is a prescription antibiotic dose pack. It contains six 250 mg tablets of azithromycin taken over 5 days.
Z-Paks can treat several bacterial infections, ranging from pneumonia to skin infections. Common Z-Pak side effects include diarrhea, nausea, and stomach pain.
Z-Paks are widely available as a lower-cost generic. GoodRx can help you save over 70% off the average retail price at certain pharmacies.
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The Z-Pak, or Zithromax Z-Pak, is an antibiotic medication that unfairly gets a bad rap. True, it’s often incorrectly prescribed for sinus infections caused by viruses, which don’t respond to antibiotics. But Z-Paks still offer benefits for those who need it.
Here are some of the reasons why a Z-Pak may be a relevant treatment option in various situations.
Overview: What is a Z-Pak?
A Z-Pak is pre-packaged prescription medication that contains 6 tablets of azithromycin (Zithromax). Azithromycin itself is an antibiotic that treats a variety of health conditions. It works by stopping the growth of certain types of bacteria, but it doesn’t work against viruses.
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Z-Paks are easy to use, generally affordable, and highly effective. Azithromycin is quickly absorbed when you take it by mouth. It easily enters your body’s tissue so it can fight the bacteria causing your infection and stays active for a relatively long time.
Several other antibiotics in its class, such as clarithromycin, have many drug interactions. Azithromycin doesn’t have the same interactions, but there are a few you should still know about. Examples include statins, heart rhythm medications, and antacids.
Z-Paks for strep throat, pneumonia, bronchitis, and more
A Z-Pak is typically prescribed for convenience to treat bacterial infections that are sensitive to azithromycin. It contains the exact number of tablets you’d need for certain infections and health conditions, at the right dose. Here are four popular examples:
Strep throat: Azithromycin is FDA approved to treat strep throat. Penicillin antibiotics are usually a first-choice treatment for this infection. But a Z-Pak may be a good option if you have a penicillin allergy.
Skin and soft tissue infections: Skin and soft tissue infections affect various tissues in the body, like muscles and tendons. These infections are commonly caused by Staph and Strep bacteria and can be treated with Z-Paks. They’re not typically a first-choice option, though.
Community-acquired pneumonia: Z-Paks can be a useful treatment option for mild cases of pneumonia that aren’t acquired in a healthcare office or hospital.
Acute worsening of chronic bronchitis: People with chronic bronchitis can develop a bacterial infection that causes their symptoms to worsen. This is treatable with either a Z-Pak or a Tri-Pak. A Tri-Pak contains three 500 mg tablets instead of the six 250 mg tablets found in a Z-Pak.
Can Z-Paks help treat or prevent other conditions?
Yes, azithromycin can be prescribed in other situations too. Outside of the 6-tablet Z-Pak, azithromycin is available in other doses and formulations. These versions of the medication can be prescribed to prevent or treat conditions such as:
Acute bacterial sinusitis: Penicillin antibiotics are a first-choice treatment for acute bacterial sinusitis. But azithromycin is a good option if you’re allergic to those medications. It’s typically treated with a Tri-Pak.
Chlamydia: Azithromycin can treat the sexually transmitted infection chlamydia. Most people take a single, 1-gram dose.
Travelers’ diarrhea: According to the CDC, azithromycin may be used to treat moderate travelers’ diarrhea. And it’s the preferred treatment for severe cases.
Certain urethra infections: A single 1 gram dose of azithromycin can treat certain urethra infections (urethritis) in men.
Chronic lung diseases: For people living with chronic obstructive pulmonary disease (COPD), researchers found that daily 250 mg doses of azithromycin reduced exacerbations (sudden worsening symptoms) and improved quality of life. Some healthcare professionals may prescribe azithromycin off-label for COPD as a result.
Certain infections in people living with severe HIV: Azithromycin is approved to prevent and treat infections caused by a bacteria called M. avium-intracellulare (MAC) in people living with severe HIV. MAC is a microorganism related to the bacteria that cause tuberculosis.
What is the typical Z-Pak dosage?
Z-Paks come as a pack of 6 tablets, and each tablet contains 250 mg of azithromycin. You’ll start by taking 2 tablets on the first day as a single dose, followed by 1 tablet on days 2 through 5. For children, the dosage is typically based on their body weight and what condition is being treated.
It’s important to take your Z-Pak as prescribed. Try to take it at the same time every day and make sure to finish taking the entire Z-Pak, even if you start to feel better. Not completing your treatment can increase the risk that your infection returns or cause azithromycin to stop working as well against the bacteria, which is known as antibiotic resistance. This makes the bacterial infections more difficult to treat.
Are there any side effects associated with Z-Paks?
As with many medications, you may experience side effects while taking a Z-Pak. Most commonly, these include:
Diarrhea
Nausea
Abdominal pain
Vomiting
Z-Pak side effects: From diarrhea and nausea to heart rhythm changes, read up on possible side effects to be aware of while taking a Z-Pak (azithromycin).
First-hand accounts: Real people share their experiences taking a Z-Pak.
A convenient prescription: Learn about typical Z-Pak dosages for kids and adults.
Higher azithromycin doses are typically associated with a greater risk of side effects. In other words, a single 1-gram dose may be more likely to cause side effects than lower doses over a few days, like with a Z-Pak.
Other more serious side effects are also possible, but rare. This includes liver damage and severe skin reactions, including Stevens-Johnson syndrome. Compared to other antibiotics, a Z-Pak may be less likely to cause Clostridium difficile (“C. diff”) infection, but it can still happen. C. diff infections are very contagious and can cause watery diarrhea, stomach cramps, and fever.
Z-Paks and other azithromycin products also have a warning of heart rhythm problems. More on that next.
Do Z-Paks come with any heart risks?
Azithromycin has been shown to prolong the QT interval. This means it takes more time for your heart to reset between beats. A long QT interval can increase the risk of potentially life-threatening abnormal heart rhythms. The FDA put out a warning about this risk in 2013.
However, a 2017 population-based study of over 14 million people examined this risk with azithromycin. It found no increased risk of ventricular arrhythmia compared to another common antibiotic, amoxicillin.
Even so, it’s important to be aware of this potential risk. Let your healthcare professional know right away if you start experiencing lightheadedness, blurred vision, or fainting.
Certain health conditions and medications may increase the risk of long QT interval when combined with azithromycin. Your healthcare professional will be able to assess your risk and recommend appropriate alternatives, if needed.
How to save on a Z-Pak
There are ways to save on a Z-Pak, which is available as both a brand-name and generic medication. GoodRx can help you save over 70% off the average retail price of the generic version. Generic Z-Pak’s price at certain pharmacies is as low as $9.38 with a free GoodRx discount.
Frequently asked questions
It’s hard to say. A Z-Pak is a different type of antibiotic than amoxicillin. You can’t directly compare them, and one isn’t widely considered stronger or better than the other. Depending on the type of bacteria that’s causing an infection, it may be better to take one antibiotic over the other.
Yes, a Z-Pak is a potent antibiotic. It’s very effective when used to treat bacterial infections that are sensitive to azithromycin. For example, azithromycin has been found to be more potent than two similar antibiotics, erythromycin and clarithromycin, on certain “gram-negative” bacteria.
It’s hard to say. A Z-Pak is a different type of antibiotic than amoxicillin. You can’t directly compare them, and one isn’t widely considered stronger or better than the other. Depending on the type of bacteria that’s causing an infection, it may be better to take one antibiotic over the other.
Yes, a Z-Pak is a potent antibiotic. It’s very effective when used to treat bacterial infections that are sensitive to azithromycin. For example, azithromycin has been found to be more potent than two similar antibiotics, erythromycin and clarithromycin, on certain “gram-negative” bacteria.
The bottom line
A Z-Pak can be a convenient and effective option for treating several types of bacterial infections. Common infections that are treatable with a Z-Pak include sinusitis, chlamydia, and travelers' diarrhea. Each package contains 6 azithromycin tablets typically taken over 5 days. Common Z-Pak side effects include diarrhea, nausea, and abdominal pain. Z-Pak is available as a lower-cost generic. GoodRx can help you save over 70% off your prescription at certain pharmacies.
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References
Ahmadian, S., et al. (2021). Benefit-harm analysis of azithromycin for the prevention of acute exacerbations of chronic obstructive pulmonary disease. Thorax.
Albert, R. K., et al. (2011). Azithromycin for prevention of exacerbations of COPD. The New England Journal of Medicine.
Aring, A. M., et al. (2011). Acute rhinosinusitis in adults. American Family Physician.
Centers for Disease Control and Prevention. (2025). Travelers’ diarrhea.
Pfizer Laboratories div Pfizer. (2025). Zithromax (azithromycin) 600 mg tablets, for oral use; Zithromax (azithromycin) for oral suspension [package insert].
Pfizer Laboratories div Pfizer. (2025). Zithromax- azithromycin dihydrate tablet, film coated; Zithromax- azithromycin dihydrate powder, for suspension [package inert]. DailyMed.
ScienceDirect. (n.d.). Azithromycin.
Trifirò, G., et al. (2017). Use of azithromycin and risk of ventricular arrhythmia. Canadian Medical Association Journal.
U.S. Food and Drug Administration. (2018). FDA drug safety communication: Azithromycin (zithromax or zmax) and the risk of potentially fatal heart rhythms.
