Retrovir (Zidovudine) – Oral

Warning:

Retrovir (zidovudine) can lower blood cells that help your body fight infections and help circulate oxygen. Conditions like neutropenia and anemia may occur, especially in people with advanced human immunodeficiency virus (HIV). 

Zidovudine can also cause life-threatening effects on your liver. Severe hepatomegaly with steatosis, an enlargement of the liver accompanied by a buildup of fat cells, may develop. Lactic acidosis, a dangerous lactic acid build-up in your blood, may also occur.

Stop treatment and get emergency medical help if you have any of the following: unusual muscle pain, trouble breathing, irregular heartbeats, dizziness, vomiting, and feeling cold, tired, or very weak.

Long-term use of Retrovir may cause muscle weakness and muscle inflammation.

What Is Retrovir?

Retrovir (zidovudine) is an antiviral medicine that prevents or treats human immunodeficiency virus (HIV) in children and adults. People who are pregnant can also take Retrovir to prevent HIV from passing to the baby. It was the first drug approved to treat HIV back in 1987 and is still in use today.

As a nucleoside reverse transcriptase inhibitor, Retrovir works by blocking the replication of HIV in the body. 

Retrovir is available via prescription as a capsule, syrup, tablet, or injection.

Drug Facts

Generic Name: Zidovudine

Brand Name: Retrovir

Drug Availability: Prescription

Administration Route: Oral, Intravenous

Therapeutic Classification: Antiviral

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Zidovudine

Dosage Form: Capsule, tablet, syrup, injection

What Is Retrovir Used For?

The Food and Drug Administration (FDA) approved Retrovir for treating HIV in children and adults in combination with other antiretroviral agents. It is also used to prevent HIV transmission from a pregnant person to the infant. Retrovir is not a cure for HIV or AIDS.

How to Take Retrovir

Use this medicine exactly as directed by your healthcare provider. Follow all the directions on your medicine label. Don’t take more than you are prescribed. Ask a healthcare provider if you do not understand how to take your treatment.

Retrovir can be taken with or without food (although it is generally better tolerated when taken with food). For HIV treatment, it is usually prescribed to be taken twice daily, although dosing may vary based on different factors. Follow the dosing regimen given by your healthcare provider, as it may be different if you are using it while pregnant or if you have certain health conditions.

Do not cut your treatment regimen short, even if you start feeling better. You should talk to your healthcare provider before stopping any of your medications.

Storage

Store Retrovir capsules, tablets, and syrup in a tightly closed container at room temperature of 59 F to 77 F Keep away from moisture and light and out of the reach of children and pets. When traveling, transport Retrovir in your carry-on or your checked baggage with its original label.

Off-Label Uses

Retrovir is sometimes used in HIV-1 nonoccupational postexposure prophylaxis (nPEP) and adult T-cell leukemia-lymphoma (ATL). These are not FDA-approved uses, and there is no evidence that Retrovir effectively treats or prevents these conditions. Misusing this medication without the advice of a healthcare provider can result in severe or life-threatening side effects.

How Long Does Retrovir Take to Work?

Retrovir enters the bloodstream in a few hours and starts working. It leaves the body in a couple of days. It is not a cure for HIV or AIDS, so it must be taken for a lifetime.

What Are the Side Effects of Retrovir?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider or a pharmacist. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Common side effects of taking Retrovir can include:

Severe Side Effects

Call your healthcare provider right away if you have serious side effects. Call 911 immediately if your symptoms feel life-threatening or if you think you or someone else is having a medical emergency. Serious side effects can include the following:

  • Lactic acidosis (buildup of lactic acid in the bloodstream)
  • Hepatomegaly (enlarged liver with fatty acid buildup)
  • Pancreatitis (inflammation of the pancreas)
  • Severe anemia
  • Neutropenia (low levels of neutrophils, a type of white blood cell, in the blood)
  • Pancytopenia (a low number of red and white blood cells and platelets)
  • Rhabdomyolysis (a condition that causes the breakdown of muscles)
  • Anaphylaxis (life-threatening allergic reaction)
  • A dangerous skin reaction called Stevens-Johnson syndrome
  • Toxic epidermal necrolysis (a potentially life-threatening skin disorder)
  • Immune reconstitution syndrome (excessive immune response to Retrovir)

Long-Term Side Effects

Retrovir affects your immune system, which may cause certain side effects (even weeks or months after you've used this medicine). Tell your healthcare provider if you are experiencing unusual signs or symptoms.

Report Side Effects

Retrovir may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Retrovir Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For HIV infection:
    • For oral dosage forms (capsules, solution, syrup, and tablets):
      • Adults—300 milligrams (mg) 2 times a day in combination with other anti-HIV medicines.
      • Children and infants 4 weeks of age and older—Dose is based on body weight or body size and must be determined by your child's doctor.
        • Weighs 30 kilograms (kg) or more—600 milligrams (mg) per day or 480 milligrams per square meter of body surface area (mg/m²) a day in divided doses.
        • Weighs 9 kg to less than 30 kg—18 mg per kg per day in divided doses.
        • Weighs 4 kg to less than 9 kg—24 mg per kg per day in divided doses.
        .
  • To help prevent pregnant women from passing HIV to their babies during pregnancy and at birth:
    • For oral dosage form (capsules, syrup):
      • Pregnant women (after 14 weeks of pregnancy, up to the start of labor)—100 milligrams (mg) 5 times a day until the start of labor.
      • Newborn infants—Dose is based on body weight and must be determined by your doctor. The usual dose is 2 milligrams (mg) per kilogram (kg) of body weight every 6 hours starting 12 hours after birth and continuing through 6 weeks of age.
    • For oral dosage form (solution):
      • Pregnant women (after 14 weeks of pregnancy, up to the start of labor)—100 milligrams (mg) 5 times a day, 200 mg every 8 hours, or 300 mg every 12 hours until the start of labor.
      • Newborn infants—Dose is based on body weight and must be determined by your doctor. The usual dose is 2 milligrams (mg) per kilogram (kg) (0.9 mg per pound) of body weight every 6 hours starting within 8 to 12 hours of birth and continuing through 6 weeks of age.

Modifications

Retrovir comes in several forms, including capsules, tablets, and syrup, that are taken orally. The syrup may be prescribed for people who are unable to swallow the capsules. Talk to your healthcare provider about which dosage is best for you.

Other factors that may affect your treatment with Retrovir include:

  • Pregnancy
  • Breastfeeding
  • Age
  • Kidney or liver issues

Pregnancy

Your healthcare provider may delay starting this medication until after the first trimester as the fetus is most susceptible to the harmful effects of drugs during the first 10 weeks of gestation.

The risks of taking Retrovir during that period are not fully known. It was only studied in women who were pregnant for 14 or more weeks. Talk to your healthcare provider if you are pregnant or may become pregnant while taking this medication.


Lactation

The Centers for Disease Control and Prevention (CDC) recommends that people living with HIV do not breastfeed their infants to prevent HIV transmission. Retrovir is also present in human milk, so the baby may experience adverse reactions or develop viral resistance if also HIV-positive. For these reasons, mothers taking Retrovir should not breastfeed.


Use in Children

Retrovir has been studied in infants and children. The liquid solution formulation may be a better option for this population. Due to the small volume of Retrovir administered to newborns, caregivers should always use an appropriate-sized syringe with 0.1 milliliter graduation to ensure accurate dosing of the oral solution.


Kidney Problems

Some Retrovir leaves the body through the kidneys. Hence, people with severe kidney disease may need to take a lower dose. 


Liver Conditions

Retrovir is primarily eliminated by the liver, and its concentrations appear to be increased in people with liver disease. Your healthcare provider may monitor you more closely if you are taking Retrovir and have liver problems.

Overdose: What Happens If I Take Too Much Retrovir?

Retrovir overdose can happen if you take too much of it. Overdoses have been reported in amounts up to 50 grams in children and adults. Signs of Retrovir overdose symptoms are similar to those listed as side effects, including headache and vomiting.

What Happens If I Take Too Much Retrovir

If you think you or someone else may have overdosed on Retrovir, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Retrovir, call 911 immediately.

Precautions

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It is very important that your doctor check your or your child's progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Zidovudine may cause blood problems. These problems may result in a greater chance of certain infections and slow healing. Therefore, you should be careful when using regular toothbrushes, dental floss, and toothpicks not to damage your or your child's gums. Check with your or your child's medical doctor or dentist if you have any questions about proper oral hygiene (mouth care) during treatment with this medicine.

Check with your doctor if you or your child has muscle pain, tenderness, wasting, or unusual tiredness or weakness while you are using this medicine.

Zidovudine may cause blood and bone marrow problems. Symptoms of bone marrow problems include fever, chills, sore throat pale skin, or unusual tiredness or weakness. These problems may require blood transfusions or temporarily stopping treatment with zidovudine. Check with your or your child's doctor if any new health problems or symptoms occur while you or your child are taking zidovudine.

Two rare but serious reactions to this medicine are lactic acidosis (too much acid in the blood) and liver toxicity, which includes an enlarged liver. These are more common if you are female, very overweight (obese), or have been taking anti-HIV medicines for a long time. Call your doctor right away if you or your child have more than one of these symptoms: abdominal discomfort or cramping, dark urine, decreased appetite, diarrhea, general feeling of discomfort, light-colored stools, muscle cramping or pain, nausea, unusual tiredness or weakness, trouble breathing, vomiting, or yellow eyes or skin.

Your immune system may get stronger when you start taking HIV medicines. Tell your doctor right away if you or your child notices any changes in your health. Sometimes the immune system will start to fight infections that were hidden in your body, such as pneumonia or tuberculosis. Autoimmune disorders (eg, Graves' disease, polymyositis, or Guillain-Barré syndrome) may also occur.

This medicine may decrease or lose body fat, especially in your face, arms, legs, or buttocks, when this medicine is used for a long time. Talk to your doctor if you have concerns.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are the Reasons I Shouldn’t Take Retrovir?

Avoid taking Retrovir if you are allergic to zidovudine or any other ingredients in Retrovir.

What Other Medications Interact With Retrovir?

Be aware of these medications when taking Retrovir, as they can affect how it works in the body.


Drugs that can interact with Retrovir include:


Antiretroviral Agents

Avoid combining Retrovir with certain other antiretroviral agents as both would work against each other in the body. Examples include:

  • Norvir (ritonavir)
  • Zerit (stavudine)


Doxorubicin

Avoid combining this anticancer drug with Retrovir as both would work against each other in the body.


Hematologic/Bone Marrow Suppressive/Cytotoxic Agents

Taking Retrovir with these drugs may increase the risk of bone marrow suppression, leading to fewer blood cells. Examples include:

Rifampin

Avoid combining rifampin with Retrovir as it may decrease Retrovir levels and affect how well it works.


Methadone

Methadone can increase Retrovir levels, even to a toxic level. Avoid combining these drugs. 

This is not a complete list of medications that may affect how Retrovir works. Tell your healthcare provider or pharmacist about all your current medicines and supplements. Some medicines can increase the risk of severe side effects from Retrovir.

What Medications Are Similar?

Medications similar to Retrovir include:

  • Ziagen (abacavir)
  • Zerit (stavudine)
  • Vemlidy, Viread (tenofovir)


Ziagen (Abacavir)

Abacavir is an antiviral medicine used to treat HIV. It works by preventing HIV from multiplying in the body. It is available as a tablet and a solution. Unlike Retrovir, it does not require dosage adjustments in those with kidney disease.

Hence, it may be a better option for this population. You should not take this medicine if you have a gene variation called the HLA-B*5701 allele. Your healthcare provider should test for this gene variation before taking this medication.


Zerit (Stavudine)

Zerit is an antiviral medicine used to treat HIV in children and adults. It works in the same way as Retrovir. Like Retrovir, it has a higher risk of causing lactic acidosis. It can be taken with or without food. The liquid formulation of Zerit must be refrigerated, which may not be a good fit for people who spend significant time away from home.  


Vemlidy, Viread (Tenofovir)

Tenofovir is an antiviral medicine used to treat HIV in adults and children at least two years old. It also treats hepatitis B. It is available in two forms: tenofovir alafenamide and disoproxil. Similar to Retrovir, it works by preventing HIV from multiplying in the body. It must be taken with food and swallowed whole.

It can severely affect the kidneys (Fanconi syndrome) and bones (osteoporosis). However, these side effects are decreased with tenofovir alafenamide.

Frequently Asked Questions

  • What Is Retrovir used for?

    Retrovir treats HIV in children and adults in combination with other antiretroviral agents. It also prevents the transmission of HIV from a pregnant person to their child. It does not cure HIV or AIDS.

  • Will Retrovir prevent me from transmitting HIV to my baby?

    Retrovir is used to prevent HIV transmission from a pregnant person to their infant. However, the transmission may still occur in some cases despite treatment. This medication is not a cure for HIV or AIDS.

  • What are the side effects of Retrovir?

    Some of the most commonly reported adverse reactions in adults are headaches, feeling unwell, nausea, loss of appetite, and vomiting. Most frequently reported symptoms in children are fever, cough, and digestive issues.

    Contact your healthcare provider if you experience muscle weakness, shortness of breath, symptoms of hepatitis or pancreatitis, or any other unexpected adverse events while taking Retrovir.

How Can I Stay Healthy While Taking Retrovir?

While there is still no cure for HIV, several available treatment options can extend the life of a person living with the virus. Retrovir is vital in treating HIV and preventing transmission to an infant during pregnancy.

People using Retrovir for this condition are at risk for serious side effects. Do not use this medicine to treat any condition your healthcare provider has not checked. If you have trouble remembering to take this medication, consider setting alarms on your phone or calendar. 

As with any medication, ask your healthcare provider or pharmacist any questions.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Jain S, Mayer KH. Practical guidance for nonoccupational postexposure prophylaxis to prevent HIV infection: an editorial review. AIDS. 2014;28(11):1545-54. doi:10.1097/QAD.0000000000000301

  3. El Hajj H, Tsukasaki K, Cheminant M, et al. Novel treatments of adult T cell leukemia lymphoma. Front Microbiol. 2020;11:1062. doi:10.3389/fmicb.2020.01062

  4. Centers for Disease Control and Prevention. Human immunodeficiency virus (HIV).

  5. Food and Drug Administration. Ziagen label.

  6. Food and Drug Administration. Zerit label.

  7. Food and Drug Administration. Vemlidy label.

  8. Food and Drug Administration. Viread label.

  9. Gupta SK, Post FA, Arribas JR, et al. Renal safety of tenofovir alafenamide vs. tenofovir disoproxil fumarate: a pooled analysis of 26 clinical trials. AIDS. 2019;33(9):1355-1365. doi:10.1097/QAD.0000000000002223