Common brand names

• Retrovir

How it is administered

Zidovudine is available in several forms for oral and intravenous (IV) use:

• Oral solution: Each mL contains 10 mg of zidovudine. This is often used for patients who have difficulty swallowing pills.
• Capsules/Tablets: Each capsule or tablet typically contains 100 mg or 300 mg of zidovudine.
• IV injection: For patients unable to take oral medication, zidovudine can be given as an intravenous infusion.

The usual adult oral dose for HIV-1 infection is 300 mg twice daily in combination with other antiretroviral agents. Dosage may be adjusted for pediatric patients, those with renal or hepatic impairment, or for prevention of maternal-fetal transmission of HIV-1.

How it works

Zidovudine is a type of medication known as a nucleoside reverse transcriptase inhibitor (NRTI). It works by interfering with the ability of viruses like HIV-1 to make copies of themselves inside the body.

Once inside the body, zidovudine is converted to its active form, zidovudine triphosphate (ZDV-TP). This active form blocks an enzyme called reverse transcriptase, which is essential for the virus to replicate its genetic material. By blocking this enzyme, zidovudine helps prevent the virus from multiplying and spreading to new cells.

Although zidovudine is not a cure for HIV or other viral infections, it helps to lower the amount of virus in the body, maintain immune function, and reduce the risk of complications. It is always used in combination with other antiretroviral drugs to increase its effectiveness and reduce the risk of drug resistance.

Who should take it

Zidovudine is indicated for:

• The treatment of Human Immunodeficiency Virus (HIV-1) infection in combination with other antiretroviral agents.
• The prevention of maternal-fetal HIV-1 transmission (given to pregnant women and their newborns).

It is not specifically indicated for Adult T-cell Leukemia/Lymphoma (ATLL) or other blood cancers, but may be used in certain clinical situations where HIV infection is present or for research purposes. For HIV-1, zidovudine helps to reduce the viral load and maintain immune function. In pregnant women with HIV-1, it is used to reduce the risk of passing the virus to the baby during pregnancy, labor, and delivery.

Who should not take it

Zidovudine should not be used in patients who have had a potentially life-threatening hypersensitivity reaction (such as anaphylaxis or Stevens-Johnson syndrome) to zidovudine or any of its components.

Caution is advised in patients with significant bone marrow compromise, such as those with low granulocyte counts (<1,000 cells/mm³) or low hemoglobin (<9.5 g/dL), as zidovudine can cause or worsen anemia and neutropenia. It should also be used with caution in patients with liver disease, as it can cause lactic acidosis and severe hepatomegaly with steatosis. Zidovudine is not recommended for patients with severe anemia or neutropenia unless the benefits outweigh the risks.

Commonly used with

Zidovudine is almost always used in combination with other antiretroviral medications to treat HIV-1 infection. Common partners include:

• Lamivudine (another NRTI)
• Protease inhibitors (such as indinavir)
• Non-nucleoside reverse transcriptase inhibitors (NNRTIs)

Combining zidovudine with other antiretrovirals helps to increase the effectiveness of treatment and reduce the risk of the virus becoming resistant to the medication.

Commonly tested with

Zidovudine has been tested in combination with several other antiretroviral agents, most notably lamivudine and indinavir, as part of multi-drug regimens for HIV-1 infection. It has also been studied with interferon alfa and ribavirin in patients co-infected with HIV-1 and hepatitis C virus (HCV), though this combination can increase the risk of anemia and is generally not recommended.

Zidovudine should not be used with stavudine or doxorubicin due to antagonistic effects. It is also important to avoid combining it with other bone marrow suppressive or cytotoxic agents unless closely monitored.