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An Overview of Retrovir (Zidovudine, AZT)

February 15, 2017

Brand Name: Retrovir
Other Name(s): AZT, ZDV, azidothymidine
Drug Class: Nucleoside Reverse Transcriptase Inhibitors

Retrovir pill


Zidovudine can cause serious, life-threatening side effects. These include hypersensitivity reaction or rash, lactic acidosis (buildup of lactic acid in the blood), liver problems, muscle weakness (myopathy), and blood disorders such as severe anemia (extremely reduced numbers of red blood cells) or neutropenia (reduced numbers of white blood cells).

Contact your health care provider right away if you have any of the following symptoms:

  • Rash
  • Unusual breathing
  • Shortness of breath
  • Unusual bleeding or bruising
  • Unusual tiredness or weakness
  • Pale skin
  • Fever
  • Chills
  • Sore throat
  • Fatigue
  • Loss of appetite
  • Upset stomach
  • Vomiting
  • Dark-colored urine
  • Yellowing of your skin or the whites of your eyes (jaundice)
  • Light-colored bowel movements
  • Muscle weakness
  • Lack of strength
  • Muscle pain
  • Pain in the upper right part of your stomach

Zidovudine can cause blood disorders such as severe anemia (extremely reduced numbers of red blood cells) or neutropenia (reduced numbers of white blood cells). Your health care provider may follow your blood count closely while you are taking zidovudine.

Worsening of liver disease (sometimes resulting in death) has occurred in people infected with both HIV and hepatitis C virus (HCV) who were taking HIV medicines and also being treated for HCV infection with interferon with or without ribavirin. If you are taking zidovudine as well as interferon with or without ribavirin and you experience side effects, tell your health care provider.

While taking zidovudine, it is important to keep all of your appointments with your health care provider.

What Is Zidovudine?

Zidovudine is a prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the following uses:

  • Treatment of HIV infection in adults and children 4 weeks of age and older. When zidovudine is used to treat HIV infection, the medicine is always used in combination with other HIV medicines.
  • Prevention of mother-to-child transmission of HIV. When used to prevent mother-to-child transmission, zidovudine is given to HIV-infected women during pregnancy and childbirth and to their infants for 6 weeks after birth.

Zidovudine belongs to a class (group) of HIV drugs called nucleoside reverse transcriptase inhibitors (NRTIs). NRTIs block an HIV enzyme called reverse transcriptase. (An enzyme is a protein that starts or increases the speed of a chemical reaction.) By blocking reverse transcriptase, NRTIs prevent HIV from multiplying and can reduce the amount of HIV in the body.

HIV medicines can't cure HIV/AIDS, but taking a combination of HIV medicines (called an HIV treatment regimen) every day helps people with HIV live longer, healthier lives. HIV medicines also reduce the risk of HIV transmission. However, despite use of zidovudine to prevent mother-to-child transmission of HIV, some cases of HIV infection can still occur.

Zidovudine may also be used "off-label" to treat some conditions associated with human herpesvirus-8 (HHV-8) infection in people with HIV. For information on the off-label HIV-related use of zidovudine, please refer to the HHV-8 section of the Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents.


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

Before taking zidovudine, tell your health care provider:

  • If you are allergic to zidovudine or any other medicines.
  • If you have or have ever had liver or kidney disease.
  • If you have or have ever had bleeding, anemia, or other blood problems.
  • If you have or have ever had any disease or swelling of the muscles.
  • If you have or have had any other medical conditions.
  • If you drink alcohol or have a history of alcohol abuse.
  • If you are pregnant or plan to become pregnant. Despite use of zidovudine to prevent mother-to-child transmission of HIV, some cases of HIV infection can still occur. Whether exposure to zidovudine in the womb or after birth can harm a baby in the long term is unknown. Talk to your health care provider about possible risks with taking zidovudine when pregnant.
  • If you are breastfeeding or plan to breastfeed. Do not breastfeed if you are infected with HIV or are taking zidovudine.
  • If you are using hormone-based birth control (such as pills, implants, or vaginal rings). For more information about using birth control and HIV medicines at the same time, view the AIDSinfo HIV and Birth Control infographic.
  • About other prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Zidovudine may affect the way other medicines or products work, and other medicines or products may affect how zidovudine works. Taking zidovudine together with certain medicines or products may cause serious, life-threatening side effects.

How Should I Take Zidovudine?

Zidovudine (brand name: Retrovir) comes in the following forms and strengths:

  • 300-mg tablets.
  • 100-mg capsules.
  • 10-mg/mL syrup.
  • 20-mL single-use vials for intravenous (IV) injection. Each vial contains 200 mg of zidovudine in 20 mL solution (a solution is a mixture of a medicine and a liquid).

Take zidovudine according to your health care provider's instructions.

Take zidovudine tablets, capsules, and syrup with or without food.

Before use, zidovudine solution for IV injection is diluted with dextrose (sugar) dissolved in water. The diluted solution is injected slowly (infused) over 1 hour through a needle or catheter into a vein.

If you take too much zidovudine, contact your health care provider or local poison control center (1-800-222-1222) right away, or go to the nearest hospital emergency room.

For more information on how to take zidovudine capsules and syrup, see the FDA drug label from DailyMed. (DailyMed is a federal website that includes the most recent drug labels submitted to FDA.) For more information on how to take zidovudine for IV injection, see the drug summary from MedlinePlus.

What Should I Do if I Forget a Dose?

If you are taking zidovudine by mouth (capsules or syrup) and forget a dose, take the missed dose as soon as you remember it. But if it is almost time for your next dose, skip the missed dose and just take your next dose at the regular time. Do not take two doses at the same time to make up for a missed dose.

If you or your child is taking zidovudine by infusion, your health care provider may tell you to stop the infusion if there is a mechanical problem such as blockage in the tubing, needle, or catheter. If you have to stop an infusion, call your health care provider immediately so your therapy can continue after the problem is resolved.

What Side Effects Can Zidovudine Cause?

Zidovudine may cause side effects. Most side effects from zidovudine are manageable, but a few can be serious. Serious side effects include lactic acidosis (buildup of acid in the blood), liver problems, muscle weakness (myopathy), and blood disorders such as severe anemia (extremely reduced numbers of red blood cells) or neutropenia (reduced numbers of white blood cells). (See the WARNING box above).

Other possible side effects of zidovudine include:

  • Immune reconstitution inflammatory syndrome (IRIS), a condition that sometimes occurs when the immune system begins to recover after treatment with an HIV medicine. As the immune system gets stronger, it may have an increased response to a previously hidden infection.
  • Changes in body fat (including gain or loss of fat).

Tell your health care provider if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of zidovudine. To learn more about possible side effects of zidovudine, read the drug label or package insert or talk to your health care provider or pharmacist.

The AIDSinfo fact sheet on HIV Medicines and Side Effects also includes information that may apply to zidovudine.

You can also report side effects to FDA at 1-800-FDA-1088 (1-800-332-1088) or online at

How Should Zidovudine Be Stored?

  • Store zidovudine capsules and syrup at 59°F to 77°F (15°C to 25°C). Protect zidovudine capsules from moisture.
  • Keep zidovudine in the container that it came in and keep the container tightly closed.
  • Do not use zidovudine if the original seal over the bottle opening is broken or missing.
  • Store vials of zidovudine for IV injection at 59°F to 77°F (15°C to 25°C) and protect them from light.
  • Once zidovudine for IV injection is diluted, use the solution within 8 hours if stored at 59°F to 77°F (15°C to 25°C) or 24 hours if refrigerated at 36°F to 46°F (2°C to 8°C).
  • Throw away zidovudine that is no longer needed or expired (out of date). Follow FDA guidelines on how to safely dispose of unused medicine.
  • Keep zidovudine and all medicines out of reach of children.

Where Can I Find More Information About Zidovudine?

More information about zidovudine is available:

Manufacturer Information

ViiV Healthcare
Main number: 877-844-8872
Patient assistance (ViiV Connect): 844-588-3288

The above Patient Version drug summary is based on the following FDA label(s): Capsule, syrup, tablet (film coated), injection (solution).

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This article was provided by AIDSinfo. Visit the AIDSinfo website to find out more about their activities and publications.

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