10 Azithromycin Side Effects You Should Know About

Getting sick happens. And sometimes, you need an antibiotic to start feeling better. 

Azithromycin (Zithromax), commonly referred to as a Z-Pak, is a macrolide antibiotic that’s been around for a while. You’ve likely heard of it before, or maybe you’ve even taken it in the past. 

Azithromycin, which treats several different bacterial infections, is generally well tolerated. But, like with all medications, there are some notable azithromycin side effects to be aware of. 

Azithromycin side effects at a glance

Most people don’t experience many side effects with azithromycin. When it does cause side effects, though, they’re usually mild and can be managed at home.

Common, typically mild azithromycin side effects include: 

• Diarrhea

• Nausea or vomiting

• Stomach pain

• Gassiness

• Fatigue

• Headaches

• Dizziness

• Itchy skin

• Loss of appetite

• Taste changes

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Rare but serious azithromycin side effects include:

• Liver damage

• Severe skin reactions

• Heart rhythm problems

• Infectious diarrhea

Knowing about the possible side effects of azithromycin can help you manage them better if they happen. Here, we’ll take a closer look at 10 azithromycin side effects you should know about. 

1. Diarrhea

Diarrhea is the most common side effect of azithromycin. In clinical trials, up to 5% of people taking azithromycin reported experiencing diarrhea.

If you have diarrhea related to azithromycin, there are strategies to manage it. Temporary diet changes can help in milder cases. Try to avoid spicy, greasy, or high-fiber foods, such as wheat bread, lentils, and broccoli. There are also over-the-counter (OTC) products, such as loperamide (Imodium A-D) and probiotics, that may help. 

It's also important to stay hydrated by drinking clear liquids if you experience diarrhea. This helps replace fluids lost from diarrhea.

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2. Nausea and vomiting

Nausea is another relatively common azithromycin side effect. Vomiting is less likely, but it’s also possible. 

If you have an upset stomach while taking azithromycin, consider taking your upcoming doses with food. This can help ease nausea. 

Temporary diet changes can help with mild nausea and vomiting, too. Eating smaller meals and avoiding strong-smelling or high-fat items can lessen nausea, for example. OTC anti-nausea medications are also available, if needed. 

3. Stomach pain

Mild-to-moderate stomach pain is another possible side effect of azithromycin.

Stomach pain related to azithromycin usually goes away on its own. Though, while rare, severe stomach pain is possible and could be a sign of something more serious, such as liver damage or a Clostridioides difficile (C. diff) infection. This infection can cause severe, infectious diarrhea. You may experience watery diarrhea along with stomach pain and fever.

If you experience stomach pain that’s bothersome or doesn’t go away, contact your prescriber right away.

4. Loss of appetite

You might notice that you’re not as hungry while taking azithromycin. This has been reported by a number of people taking the antibiotic.

If you find yourself eating less or not feeling hungry, it’s important to try to maintain a balanced diet to support your immune system while you recover.

It may be helpful to eat smaller, more frequent meals. Focus on foods that are easy to digest, such as soups, smoothies, and soft fruits. And try to avoid foods high in sugar, such as candy and soda.

If your appetite doesn’t return after you stop taking azithromycin, be sure to let your prescriber know. Going without an adequate amount of food for too long can be dangerous.

5. Headaches

Headaches are possible with azithromycin. They’re usually mild and can be managed with OTC headache medications, such as acetaminophen (Tylenol) or ibuprofen (Advil, Motrin). Staying hydrated and getting quality sleep, when possible, can also ease headache pain.

Good to know: Some people take decongestants, such as pseudoephedrine (Sudafed), when they’re feeling sick. But pseudoephedrine can cause headaches as a side effect. Try to avoid decongestants and other medications that cause headaches while taking azithromycin. 

6. Feeling tired or dizzy

It’s normal to feel more tired than usual when you’re sick. But some people feel extra fatigued while taking azithromycin. 

If this happens to you, rest assured that it’s normal. Try to stick to a regular sleep schedule and make sure you’re getting enough rest.

Some people also report feeling dizzy while taking azithromycin. You may be more likely to experience this side effect if you have a history of heart rhythm changes or low blood pressure.

If you start to feel unsteady on your feet, find a safe place to sit down and try to avoid moving suddenly. Drinking water or eating a small snack may also help.

7. Changes to your sense of taste

In rare cases, people report changes in their sense of taste after starting azithromycin. This includes having bitter or sour taste in the mouth, which can make certain foods taste weird or different than normal. Loss of taste is also possible.

Taste changes related to azithromycin are usually temporary and resolve once the medication is stopped. In the meantime, chewing sugar-free gum or eating flavorful foods can help mask unusual tastes.

8. Changes in heart rhythm

Azithromycin can cause irregular heart rhythms in some people. This is more likely among older adults, people with low blood levels of potassium or magnesium, and people taking heart rhythm medications (antiarrhythmics). People with certain heart conditions, such as long QT syndrome, are also at a higher risk.

Reports of this side effect prompted the FDA to release a drug safety warning in 2013. In rare cases, these heart rhythm changes have been fatal. So be sure your prescriber knows your full medical history and has a list of all the medications and supplements you take, so they can help you manage this risk.

9. Liver damage

Changes in liver health related to azithromycin are uncommon, but possible. In clinical trials, liver function tests (blood tests that evaluate liver health) slightly worsened in a small number of people taking azithromycin. 

This side effect is usually reversible once the medication is stopped. But, in rare cases, azithromycin has been known to contribute to actual liver damage. This is a serious side effect that can be life-threatening for some people. The risk of liver damage related to azithromycin is higher for people who have had liver problems in the past.

Symptoms of liver damage can include nausea or vomiting, yellowing of the skin or eyes (jaundice), and intense stomach pain. Be sure to let your prescriber know if you have a history of liver problems before starting azithromycin.

10. Serious skin reactions

In rare cases, azithromycin can cause serious skin reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome. These skin conditions can be dangerous if left untreated. 

As a precaution, if you develop a new rash while taking azithromycin, it’s recommended to contact your prescriber as soon as you can. This should be done to make sure the rash isn’t a sign of something more serious. 

If the rash isn’t serious, your prescriber may just recommend applying a cool compress, such as a wet washcloth or ice pack, to the affected area. They may also recommend trying an OTC product, such as hydrocortisone cream, to help relieve redness or itching.

If you develop painful skin blisters or a significant rash while taking azithromycin, your prescriber will likely want you to seek emergency medical care.

How long do azithromycin side effects last?

Mild side effects — such as appetite changes, fatigue, and headaches — typically get better within a few days of starting azithromycin. And most side effects resolve after the medication is stopped.

There are some exceptions to this, though. More serious side effects like liver damage and severe skin reactions usually require medical attention and take more time to go away. 

If you experience any side effects that feel severe, call 911 or go to the nearest ER without delay.

Remember: Keep taking azithromycin until you run out of your prescribed doses, even if you’re feeling better. Completing your full course of antibiotics will help your body get rid of any residual bacteria that could make you sick again.

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Written by:

Taylor K. Clarke, PharmD

Taylor K. Clarke, PharmD, has 8 years of pharmacy experience working in community practice, hospital pharmacy, and ambulatory care pharmacy. Taylor's commitment to patient education motivated her to pursue health communications as a pharmacist.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

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