An Overview of Azithromycin (Zithromax)

Other Names: Zithromax, Zmax, azithromycin dihydrate
Drug Class: Opportunistic Infections and Coinfections

What Is Azithromycin?

Azithromycin is an antibacterial prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of certain bacterial infections, such as:

  • Various bacterial respiratory diseases, including pneumonia, acute sinus and ear infections, and acute worsening of chronic bronchitis.
  • Pelvic inflammatory disease.
  • Genital ulcer disease.
  • Infections of the urethra, cervix, throat, tonsils, and skin.

Some bacterial respiratory diseases (such as pneumonia) for which azithromycin treatment is FDA-approved are opportunistic infections (OIs) of HIV. An OI is an infection that occurs more frequently or is more severe in people with weakened immune systems -- such as people with HIV -- than in people with healthy immune systems. To learn more about opportunistic infections, read the AIDSinfo What is an Opportunistic Infection? fact sheet.

How Is Azithromycin Used in People With HIV?

The Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents include recommendations on the HIV-related uses of azithromycin.

Using a medicine as indicated on the medicine label is called on-label use; using the medicine in a different way is called off-label use. Off-label use, for example, can include using a drug for a different disease or medical condition. Good medical practice and the best interests of a patient sometimes require that a medicine be used off-label.

The guidelines include recommendations on the following uses of azithromycin:

On-label uses:

  • Treat bacterial respiratory diseases (such as pneumonia)

Off-label uses:

  • Treat:
    • Toxoplasma gondii encephalitis (also called toxoplasmosis).
    • Disseminated Mycobacterium avium complex (MAC) disease.
    • Bacterial enteric infections, including campylobacteriosis and shigellosis.
    • Certain Bartonella infections (also called bartonellis), such as infections of the bloodstream (bacteremia) and bone (osteomyelitis).
    • Syphilis.


  • Disseminated MAC disease from occurring the first time (called primary prophylaxis) and from recurring (called secondary prophylaxis or maintenance therapy).
  • Syphilis.

The above list may not include all of the HIV-related uses of azithromycin recommended in the guidelines. Some recommended uses, such as uses in certain rare circumstances, may have been omitted.

What Should I Tell My Health Care Provider Before Taking Azithromycin?

Before taking azithromycin, tell your health care provider:

  • If you are allergic to azithromycin or any other medicines.
  • About any medical conditions you have or have had, including the following:
    • Pneumonia.
    • Cystic fibrosis.
    • A problem that causes muscle weakness (myasthenia gravis).
    • A known or suspected bacteremia (bacterial infection in the blood).
    • An irregular heartbeat, especially a problem called "QT prolongation."
    • Kidney or liver problems.
  • About anything that could affect your ability to take medicines, such as difficulty swallowing pills, difficulty remembering to take pills, or any health conditions that may prevent you from receiving medicine by injection or infusion.
  • If you are pregnant or plan to become pregnant. Whether azithromycin can harm an unborn baby is unknown. Azithromycin should be used during pregnancy only if clearly needed. Talk to your health care provider about possible risks with taking azithromycin when pregnant.
  • If you are breastfeeding or plan to breastfeed. Do not breastfeed if you have HIV.
  • About other prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Especially tell your doctor if you are taking nelfinavir or warfarin. Azithromycin may affect the way other medicines or products work, and other medicines or products may affect how azithromycin works. Ask your health care provider if there are interactions between azithromycin and the other medicines you take.

Ask your health care provider about possible side effects from azithromycin. Your health care provider will tell you what to do if you have side effects.

How Should I Take Azithromycin?

Take azithromycin according to your health care provider's instructions. Your health care provider will tell you how much azithromycin to take and when to take it. Before you start azithromycin and each time you get a refill, read any printed information that comes with your medicine.

How Should Azithromycin Be Stored?

  • Store azithromycin injection vials below 86°F (30°C). Once the injection powder in the vial has been reconstituted with sterile water and diluted, it is stable for 24 hours at or below 86°F (30°C), or for 7 days if refrigerated at 41°F (5°C).
  • Store azithromycin powder for oral suspension (extended release) at or below 86°F (30°C). After mixing, store the suspension at room temperature, 59°F to 86°F (15°C to 30°C). Do not refrigerate or freeze the suspension. The suspension should be used within 12 hours of mixing.
  • Store azithromycin dry powder for oral suspension below 86°F (30°C) in a tightly closed container. Do not freeze it. After mixing, store the suspension at 41°F to 86°F (5°C to 30°C).
  • Store azithromycin tablets between 59°F and 86°F (15°C to 30°C).
  • Do not use azithromycin if the original seal over the container opening is broken or missing.
  • Throw away azithromycin that is no longer needed or expired (out of date). Follow FDA guidelines on how to safely dispose of unused medicine.
  • Keep azithromycin and all medicines out of reach of children.

Where Can I Find More Information About Azithromycin?

More information about azithromycin is available:

The above Patient Version drug summary is based on the following FDA label(s): Injection (powder, lyophilized, for solution); Powder (for suspension); Powder (for suspension), tablet (film coated).

[Note from TheBody: This article was created by AIDSinfo, who last updated it on Aug. 6, 2018. We have cross-posted it with their permission.]