Azithromycin is a generic drug that’s prescribed for bacterial infections in adults and children. As with other drugs, azithromycin can cause side effects, such as diarrhea, nausea, and abdominal pain.

Azithromycin is available as the brand-name drug Zithromax.

Azithromycin comes as an oral tablet. The drug also comes in an oral solution, eye drops, and injection, but this article does not cover them.

Read on to learn about potential common, mild, and serious side effects of azithromycin. You can get a general overview of azithromycin oral tablet, including details about its uses.

Azithromycin can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took azithromycin in clinical trials:

Mild side effects can occur with azithromycin use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to azithromycin’s prescribing information.

Mild side effects that have been reported with azithromycin include:

  • diarrhea
  • abdominal pain
  • nausea
  • headache
  • vomiting
  • upset stomach
  • fatigue
  • dizziness
  • skin rash

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews the side effects of the medication. If you develop a side effect while taking azithromycin and want to tell the FDA about it, visit MedWatch.

Azithromycin may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to azithromycin’s prescribing information.

If you develop serious side effects while taking azithromycin, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

* For more information about this side effect, see “Side effect specifics.”

ALLERGIC REACTION

For some people, azithromycin oral tablet can cause an allergic reaction. In general, symptoms of an allergic reaction can be mild or serious.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to azithromycin oral tablet, your doctor may recommend taking a different medication instead.

Azithromycin may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

How long do side effects of azithromycin last?

Generally, the side effects from azithromycin oral tablet are mild and go away as soon as the drug is stopped. (Azithromycin is meant to be a short-term treatment.)

In rare cases, azithromycin can cause side effects that last longer than usual or require extended treatment. These include liver damage or C. diff.-associated diarrhea.*

Talk with your doctor or pharmacist if you have questions about how long the side effects of azithromycin may last.

* For more information about this side effect, see “Side effect specifics.”

Is there a way to reduce the risk of side effects from azithromycin?

Azithromycin oral tablet may cause mild side effects that you can easily manage at home. However, to reduce the risk of some side effects, make sure to tell your doctor about any medications you’re taking and your health conditions. This is so they can determine if azithromycin is the safest treatment option for you.

Diarrhea is the most commonly reported side effect of azithromycin treatment. To help reduce the risk of diarrhea, your doctor may recommend eating yogurt during treatment. Diarrhea is typically mild and may be managed with small changes in your diet, such as avoiding spicy or high fiber foods. It can also be managed with an over-the-counter (OTC) product such as loperamide (Imodium).

If you experience an upset stomach while taking azithromycin, try taking your dose with food. Eating smaller meals and avoiding high fat meals can help lessen symptoms of nausea.

Headaches are a less common side effect of azithromycin but can usually be managed with an OTC pain reliever. These include acetaminophen (Tylenol) or ibuprofen (Advil).

Talk with your doctor if you experience side effects that are bothersome or don’t go away. They can recommend the best way to help manage your side effects.

Does the 500-milligram (mg) dose of azithromycin cause less side effects than larger doses?

Yes, in clinical trials certain side effects were reported more often in people taking a higher dose of azithromycin compared with those taking 500 mg.

Side effects reported more often in people taking higher doses of azithromycin include:

  • diarrhea
  • abdominal pain
  • nausea
  • vomiting

Talk with your doctor if you have questions or concerns about the dose of azithromycin prescribed for you.

Learn more about some of the side effects that azithromycin oral tablet may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for azithromycin.

Clostridioides difficile-associated diarrhea

Although not common, treatment with antibiotics, including azithromycin, may lead to diarrhea caused by a bacteria called Clostridioides difficile, or C. diff. This can occur when there is an imbalance of “good” and “bad” bacteria in the gut.

Symptoms of a C. diff. infection may include:

Generally, a C. diff. infection will occur during treatment or shortly after your last dose of azithromycin, but infections up to 2 months after stopping antibiotics have been reported. (Azithromycin is an antibiotic.) While most C. diff. infections are easy to treat, serious and life threatening infections are possible.

What you can do

If you experience diarrhea, especially diarrhea that includes any of the symptoms listed above, talk with your doctor right away. They can determine whether you need to stop taking azithromycin or can suggest ways to manage the diarrhea.

QT prolongation

QT prolongation (a type of heart problem) is possible during treatment with azithromycin. This side effect was rarely reported during the drug’s clinical trials.

Most people don’t experience any symptoms of QT prolongation, but if you do, symptoms may include:

QT prolongation can also lead to a serious heart rhythm problem called torsades de pointes. While this condition wasn’t reported during azithromycin’s clinical trials, it has been reported after the drug became available to use. Torsades de pointes doesn’t always cause symptoms but may include symptoms similar to those of QT prolongation.

Some people may have a higher risk of developing torsades de pointes. Risk factors include:

What you can do

Be sure to tell your doctor about the medications you’re taking and your full medical history before starting azithromycin treatment. If your doctor thinks you have a higher risk for developing heart problems, they may prescribe a different antibiotic for your condition. Or they may also monitor your heart health more closely during treatment.

If you experience any of the heart symptoms listed above, contact your doctor right away. If you feel you’re having a medical emergency, call 911 or your local emergency number immediately.

Before taking azithromycin oral tablet, discuss your health history with your doctor. Azithromycin may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

  • liver problems
  • heart problems
  • myasthenia gravis
  • previous allergic reaction to this or a similar drug
  • pregnancy
  • breastfeeding
  • alcohol consumption

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.