What is a Z-Pak?

In this article:

• What is a Z-Pak?
• What is a Z-Pak used for?
• How does a Z-Pak work?
• Z-Pak instructions
• Dosage
• Interactions
• Side effects
• Alternatives
• Azithromycin vs. amoxicillin
• Cost

In this article

• What is a Z-Pak?
• What is a Z-Pak used for?
• How does a Z-Pak work?
• Z-Pak instructions
• Dosage
• Interactions
• Side effects
• Alternatives
• Azithromycin vs. amoxicillin
• Cost

A Z-Pak (azithromycin) is an antibiotic commonly prescribed for certain types of bacterial infections, like acute bacterial sinus infections and tonsillitis. It is not a treatment for viral infections like the flu, common cold, or COVID-19. Keep reading to learn what a Z-Pak is, the infections it treats, its dosage requirements, side effects, and how it compares to other drugs.

What is a Z-Pak?

Z-Pak is short for Zithromax Z-Pak (azithromycin). It is a commonly prescribed antibiotic that treats certain bacterial infections by stopping the growth of bacteria in the body. “Z-Pak is the brand-name formulation for a specific antibiotic called azithromycin,” says Amesh Adalja, MD, a board-certified infectious disease physician. “It’s used for a variety of infections including pneumonia, sinus infections, and ear infections, for example.”

What is a Z-Pak (azithromycin) used for?

A Z-Pak can treat a variety of bacterial infections in adults and children. Keep in mind, however, that some infections, like sinus infections, can be either viral or bacterial. Antibiotics like azithromycin are ineffective for viral infections and the common cold. Some of the most common infections Z-Paks are prescribed for (if bacterial) include: 

• Strep throat
• Sinus infections
• Ear infections
• Skin infections
• Community-acquired pneumonia
• Bronchitis
• Certain sexually transmitted infections, such as urethritis or cervicitis caused by chlamydia bacteria*
• Pharyngitis
• Infected tonsils
• Acute bacterial exacerbations of chronic bronchitis
• Prevention of infections in HIV and AIDS patients

*Chlamydia may require higher doses of azithromycin than what’s available in a Z-Pak.

Strep throat is one of the more common diseases treated by a Z-Pak. Because bacteria cause strep throat, a Z-Pak can prevent bacteria from growing and can decrease the spread of the infection to other people. Treating strep throat can prevent it from evolving into a more severe illness like rheumatic fever, a condition that can damage the heart valves.

How does a Z-Pak work?

Zithromax Z-Pak (azithromycin) is in a class of antibiotics referred to as macrolide antibiotics. This class of drugs also includes erythromycin and clarithromycin. Macrolides work by killing bacteria or preventing their growth and are considered to be safe antibiotics. Azithromycin is commonly prescribed as an alternative to penicillin for people who need antibiotics but have penicillin allergies. Azithromycin is one of the top prescribed antibiotics in the United States.

Z-Pak (azithromycin) instructions

It’s important to take this medication as directed by your healthcare provider. The typical Z-Pak dosage is two pills on the first day, then one pill per day for the next four days. However, other doses of azithromycin may be prescribed, depending on the type of infection being treated. For the best results, take this antibiotic at approximately the same time every day and continue to take it until you finish the full prescribed amount, even if you are feeling better. If you don’t finish your course of antibiotics, bacteria may grow, and your infection may return. Stopping antibiotics early can also lead to antibiotic resistance, meaning the antibiotic may not work the next time you need it.

If you miss a Z-Pak dose, take it as soon as you can. If it’s almost time for your next dose, skip the missed dose—it’s not recommended that you take two doses at once.

You can take your Z-Pak doses with or without food.

Z-Pak (azithromycin) dosage

A Z-Pak consists of six, 250 mg tablets of azithromycin and is a five-day treatment. You take two tablets on the first day, followed by one tablet daily on each of the remaining four days.

Although Zithromax Z-Pak is the most popular form of azithromycin, healthcare providers may sometimes prescribe other dosage forms of azithromycin, such as a Zithromax Tri-Pak. This pack contains three tablets of 500 mg of azithromycin, taken once daily for three days. It may be prescribed for mild to moderate acute bacterial exacerbations of chronic bronchitis or acute bacterial sinusitis. 

Sources: DailyMed, PDR

Z-Pak (azithromycin) interactions

While Z-Paks can help adults and children recover from bacterial infections, there are some precautions to consider before taking this prescription drug. Tell your healthcare provider if you have any allergies or medical conditions, such as:

• An allergy to azithromycin or other antibiotics (this medication may cause allergic reactions in some people)
• Liver problems
• Kidney problems
• Myasthenia gravis
• Pneumonia
• Cystic fibrosis
• A history or family history of heart problems or heart rhythm problems (or if you take any medicine that causes QT prolongation)
• Recent vaccine or immunization
• Pregnancy
• Breastfeeding (the drug passes into breast milk)

Specifically, talk to your healthcare provider about any interactions with the current drugs you’re taking. This includes prescription and over-the-counter drugs as well as any vitamins or supplements you take. The following medicines interact with azithromycin:

• Amiodarone
• Antacids that contain magnesium or aluminum
• Colchicine
• Digoxin
• Disopyramide
• Dofetilide
• Dronedarone
• Ibutilide
• Nelfinavir
• Phenytoin
• Pimozide
• Procainamide
• Quinidine
• Sotalol
• Warfarin

This is not a full list of drug interactions, and others may occur. Talk to your healthcare provider about drug interactions before taking azithromycin.

RELATED: Azithromycin interactions

Can you take cold medicine with azithromycin?

Azithromycin is typically safe to take with cold medicines. For example, there are no drug interactions between azithromycin and Nyquil, so you can safely take these two drugs together to ease symptoms of a cough, sore throat, headache, fever, runny nose, and sneezing. However, before taking NyQuil or any other cough or cold medication, check with your healthcare provider or pharmacist if the medication is safe to take with your medical conditions or other medications you take. Many cough and cold medications are not safe for people with certain medical conditions, such as high blood pressure or glaucoma. 

What are the side effects of Z-Paks (azithromycin)?

The most common side effects of Z-Paks are nausea, vomiting, diarrhea, and abdominal (stomach) pain. 

According to family medicine physician Michael Rabovsky, MD, “The problem is that when you are trying to kill bacteria in your sinuses, lungs, or elsewhere, antibiotics also kill bacteria that live in your intestine that keep your digestive health in balance.” He recommends taking probiotics while on azithromycin to help restore the good bacteria in your gut. “The thing that has really been shown to help the most with preventing diarrhea is taking probiotics when taking antibiotics,” Dr. Rabovsky says. 

Drinking plenty of water and staying hydrated with oral rehydration solutions can also help ease the effects of diarrhea. 

Other common Z-Pak side effects are:

• Gas
• Dizziness
• Headache
• Itching or rash
• Fatigue or tiredness

Serious side effects of Z-Paks may include: 

• Hearing loss
• Worsening of myasthenia gravis, which can lead to increased muscle weakness
• Heart and heart rhythm problems
• Inflamed pancreas
• Liver problems and jaundice (yellowing of the skin or whites of the eyes)
• Severe stomach pain or severe, watery diarrhea which may indicate C. difficile-associated diarrhea (a severe diarrhea that can begin up to several months after antibiotic treatment) and requires immediate medical attention
• Severe skin reaction (be alert for blistering or peeling skin, red or purple rash, burning eyes, sore throat, fever) – this requires emergency medical attention
• A serious drug reaction that can affect many parts of the body (be alert for rash, fever, swollen glands, muscle aches, weakness, unusual bruising, and jaundice)

Seek medical help right away if you experience fainting, severe dizziness, a fast or irregular heartbeat, or an allergic reaction. Symptoms of an allergic reaction, which can be life-threatening, may include hives, difficulty breathing, and swelling of the face, lips, throat, or tongue. You should also seek medical treatment if any of these side effects persist or worsen.

Azithromycin has also caused abnormal changes in the electrical activity of the heart, which can lead to a potentially fatal irregular heart rhythm, according to the Food and Drug Administration (FDA). Patients at higher risk for developing this condition include those who have low blood levels of potassium or magnesium, have a slow heart rate, or use drugs that treat abnormal heart rhythms (arrhythmia).

If your baby is taking azithromycin and is irritable or vomits while eating or nursing, contact the pediatrician right away. 

Talk to your healthcare provider before taking a Z-Pak to discuss all possible side effects and drug interactions. They can provide medical advice on how to avoid or treat adverse effects. For example, taking this medicine with food could prevent an upset stomach.

Are there alternatives to Z-Pak?

Healthcare providers may prescribe clarithromycin or Augmentin as alternatives to the Z-Pak, according to Chirag Shah, MD, board-certified emergency medicine physician and co-founder of Push Health. “However, these alternatives will not always work to treat the infection for which the Z-Pak was prescribed in the first place, and consultation with one’s medical provider is recommended before changing medications.”

Azithromycin vs. amoxicillin

Amoxicillin is a commonly prescribed alternative to azithromycin. Amoxicillin can be prescribed alone or as Augmentin, which contains amoxicillin and clavulanate. Clavulanate is added to amoxicillin to prevent resistance. Here’s a side-by-side comparison of azithromycin and amoxicillin.

RELATED: Amoxicillin side effects and how to avoid them

More Z-Pak alternatives

In addition to amoxicillin, there are other alternatives to Z-Paks, such as:

• Cipro (ciprofloxacin): This affordable antibiotic is effective at treating bacterial infections, but it may have more interactions with food and drugs compared to other Z-Pak Alternatives. 
• Vibramycin (doxycycline): This antibiotic treats bacterial infections, like pneumonia, and prevents malaria. However, it may make you more sensitive to sunlight and result in sunburn or a rash.
• Keflex (cephalexin): Cephalexin is usually taken multiple times a day, which can be hard to remember for some people. It treats bone infections, UTIs, skin infections, and surgical site infections, among other bacterial infections.
• Cleocin (clindamycin): This drug is effective in treating acne when used topically, especially when combined with other acne medications. It can also be used orally for serious skin or soft tissue infections. In some cases, clindamycin can cause severe diarrhea, which can be very serious or even fatal. 
• Levofloxacin: This medicine, in the same class as Cipro, treats a variety of bacterial infections.
• Bactrim (sulfamethoxazole-trimethoprim): This medicine treats bacterial infections, but taking this medicine may make you more susceptible to sunburns.

Save on common antibiotics

Z-Pak cost without insurance

Brand-name Zithromax Z-Pak costs about $48 per box of 6 tablets without insurance. With a Zithromax Z-Pak coupon from SingleCare, you could pay as little as $4 for generic azithromycin.