Zidovudine

What is Zidovudine?

Zidovudine, also known as AZT or ZDV, is an antiretroviral medication belonging to the drug class known as nucleoside reverse transcriptase inhibitors (NRTIs). It was one of the first medications developed to treat HIV and remains in use today for specific situations.

Approved and Common Uses

Zidovudine is prescribed for:

• Treatment of HIV-1 infection in adults and children, always as part of a combination antiretroviral regimen
• Prevention of mother-to-child transmission of HIV, given to pregnant individuals with HIV during pregnancy and labor, and to newborns for a short period after birth

Zidovudine is not used as a stand-alone treatment for ongoing HIV management, because using a single antiretroviral agent allows the virus to develop resistance quickly. It is typically combined with other antiretroviral medications from different drug classes.

Available Formulations and Strengths

Zidovudine is available in several forms, including:

• Oral tablets
• Oral capsules
• Oral syrup/solution, often used for infants and young children
• Intravenous (IV) injection, used in hospital settings, such as during labor for prevention of mother-to-child transmission

What is the Recommended Dosage of Zidovudine?

Dosage of zidovudine depends on several individual factors, including:

• The condition being treated – ongoing HIV management versus short-term use for prevention of mother-to-child transmission
• Age – dosing differs significantly between adults, children, and newborns
• Body weight, particularly in pediatric and newborn dosing
• Kidney function – zidovudine is partly eliminated by the kidneys, and dose adjustments may be needed for patients with reduced kidney function
• Bone marrow function – zidovudine can affect blood cell production, so dosing may need adjustment based on blood count monitoring

Because dosing depends heavily on age, weight, the reason for treatment, and organ function, this guide does not provide specific dosing amounts. Dosing must always be determined and supervised by a physician or HIV specialist.

Patients should take zidovudine exactly as prescribed and should not skip or stop doses without consulting their treating specialist, as inconsistent dosing increases the risk of drug resistance when used for ongoing HIV treatment.

How Zidovudine Works

Zidovudine works by interfering with an enzyme called reverse transcriptase, which HIV needs to convert its genetic material (RNA) into DNA inside human cells. Zidovudine is incorporated into the growing viral DNA chain as a faulty building block, which stops the chain from being completed—a process sometimes called chain termination.

By blocking this step, zidovudine reduces the virus’s ability to multiply, helping to lower the amount of HIV in the blood (viral load) when used as part of a combination regimen. When used during pregnancy and delivery, it also helps reduce the chance that the virus passes from parent to child.

Zidovudine does not cure HIV infection. When used for ongoing treatment, it manages the virus by controlling replication and must be taken consistently, in combination with other antiretroviral medications, for as long as a treating specialist recommends.

Is a Prescription Required to Buy Zidovudine Online?

Yes. Zidovudine is available by prescription only.

Because HIV treatment and prevention of mother-to-child transmission both require careful medical supervision, patients should:

• Be evaluated by a qualified healthcare provider, typically an infectious disease specialist, HIV specialist, or an obstetric care provider working in coordination with an HIV specialist during pregnancy
• Undergo baseline and periodic laboratory testing, including blood cell counts, viral load, and kidney function
• Receive regular follow-up to monitor treatment effectiveness and detect side effects

Important safety warnings:

• Avoid purchasing zidovudine from unlicensed or unverified online sources. Counterfeit antiretroviral medications are a recognized global health concern and can lead to treatment failure and drug resistance.
• Only obtain this medication from a licensed pharmacy with a valid prescription from a qualified specialist.

Side Effects of Zidovudine

Common Side Effects

• Headache
• Nausea, vomiting, or upset stomach
• Fatigue or general weakness
• Loss of appetite
• Difficulty sleeping
• Muscle aches

Serious Side Effects

• Signs of bone marrow suppression, such as unusual paleness, extreme tiredness, shortness of breath (possible signs of anemia), or frequent infections and fever (possible signs of low white blood cell counts)
• Signs of lactic acidosis, a rare but serious condition, including unusual muscle pain or weakness, difficulty breathing, stomach pain with nausea or vomiting, or feeling unusually cold
• Signs of liver injury, such as yellowing of the skin or eyes (jaundice), dark urine, or severe fatigue, including a rare but serious form involving fatty liver
• Muscle weakness or pain that develops with long-term use (myopathy)
• Signs of a severe allergic reaction, including rash, swelling of the face or throat, or difficulty breathing

Seek immediate medical attention if signs of severe anemia, low blood cell counts with infection, lactic acidosis, liver problems, or a severe allergic reaction occur. Because zidovudine can affect bone marrow function, regular blood count monitoring is an essential part of treatment, and any unusual fatigue, paleness, or signs of infection should be reported to a healthcare provider promptly.

This list is not exhaustive. Patients should discuss their individual side effect risk with their treating physician.

Drug Interactions

Zidovudine has a number of clinically important interactions. Categories of concern include:

• Other medications that affect bone marrow function, such as certain medications used to treat other viral infections or some chemotherapy agents, which may increase the risk of low blood cell counts when combined with zidovudine
• Certain other antiretroviral medications, particularly stavudine, which should not be combined with zidovudine because both compete for the same activation process, reducing effectiveness
• Ribavirin, an antiviral medication that can increase the risk of severe anemia when combined with zidovudine
• Certain pain relievers and fever reducers, particularly when used frequently, which may increase the risk of liver-related effects
• Probenecid and certain other medications that can increase zidovudine levels in the body

Over-the-counter medications and supplements:

• Alcohol should be used cautiously, as it may increase the risk of liver-related side effects
• Frequent or high-dose use of acetaminophen (paracetamol) should be discussed with a healthcare provider due to potential effects on the liver and blood cell counts
• Herbal supplements and other over-the-counter products should be reviewed with a healthcare provider or pharmacist before use, as some may affect blood cell counts or liver function

Patients should provide their prescribing specialist with a complete list of all medications, supplements, and herbal products, as zidovudine’s interaction profile includes several serious combinations to avoid.

Safety & Important Considerations

• Bone marrow function: Zidovudine can suppress the production of red and white blood cells. Regular blood count monitoring is required throughout treatment, and dose adjustments may be needed if significant drops occur.
• Liver disease: Zidovudine carries a risk of liver-related side effects, including a rare but serious condition involving fatty liver with lactic acidosis. Patients with pre-existing liver disease require closer monitoring.
• Kidney disease: Dose adjustments may be needed in patients with reduced kidney function, since zidovudine is partly eliminated through the kidneys.
• Pregnancy and breastfeeding: Zidovudine has a well-established role in reducing mother-to-child transmission of HIV when used during pregnancy and delivery under specialist supervision. Any decisions about its use during pregnancy or breastfeeding should be made in close consultation with an HIV specialist experienced in perinatal care.
• Children and newborns: Zidovudine is used in specific, carefully calculated doses for newborns born to parents with HIV, as part of transmission-prevention protocols. Pediatric dosing requires specialist oversight.
• Monitoring requirements: Regular complete blood counts, liver function tests, and viral load/CD4 monitoring (when used for ongoing HIV treatment) are standard components of therapy.
• FDA and regulatory safety notices: Zidovudine carries recognized warnings regarding bone marrow suppression (anemia and neutropenia), lactic acidosis, and severe hepatomegaly with steatosis (fatty liver enlargement).

This medication should be used according to its approved indications. Off-label use is not addressed in this guide.

Who This Medication Is For

Zidovudine is generally prescribed for:

• Adults and children diagnosed with HIV-1 infection who are using it as part of a combination antiretroviral regimen
• Pregnant individuals with HIV, as part of a specialist-supervised plan to reduce the risk of transmitting HIV to the baby
• Newborns born to parents with HIV, for a defined short-term course after birth as part of transmission-prevention protocols

Use is determined by an HIV specialist or, in the case of pregnancy and newborn care, by a coordinated team including obstetric and pediatric HIV specialists.

Who Should Not Take Zidovudine

This medication may not be appropriate for individuals who:

• Have a known hypersensitivity or allergy to zidovudine
• Have severe bone marrow suppression, such as very low red or white blood cell counts, unless a specialist determines a carefully monitored plan is appropriate
• Are taking stavudine, due to a known interaction that reduces the effectiveness of both medications
• Are taking ribavirin, due to an increased risk of severe anemia

Important precautions apply to individuals with a history of anemia, other blood cell disorders, liver disease, or those taking other medications that affect bone marrow or liver function.

This is not a complete list. A licensed HIV specialist must review each patient’s full medical history, blood counts, and current medications before prescribing zidovudine.

What to Do If You Miss a Dose

• Take the missed dose as soon as you remember, unless it is close to the time of your next scheduled dose.
• Do not double up or take an extra dose to make up for a missed one.
• Because consistent dosing is important for maintaining viral suppression (when used for ongoing HIV treatment) or for the transmission-prevention protocol during pregnancy and newborn care, contact your treating specialist promptly if a dose is missed, especially if this happens more than once.
• If you are unsure what to do, contact your licensed HIV specialist or pharmacist for guidance rather than guessing.

Related medications to Zidovudine

Zidovudine is a nucleoside reverse transcriptase inhibitor used within HIV antiretroviral therapy. Related pages include Lamivudine and Lamivudine-Zidovudine. Combination-regimen pages should be given greater linking priority than unrelated single-agent antiretrovirals.

Storage Instructions

• Store at room temperature, generally between 68°F and 77°F (20°C to 25°C), unless otherwise directed on the label.
• Keep in the original container, protected from excess moisture and light.
• If using the oral syrup/solution form, follow specific storage instructions provided by the pharmacy, as some liquid formulations have different storage requirements.
• Avoid storing in bathrooms or other high-humidity environments.
• Keep out of reach of children and pets; use a secure or child-resistant container if young children are present in the home.
• Do not use medication that is expired or shows unusual changes beyond normal variation.

Disclaimer:

This page is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. The information provided here is not a substitute for professional medical guidance.

Patients must consult a licensed physician, infectious disease/HIV specialist, or obstetric care provider (in the case of pregnancy) before starting, changing, or stopping this medication. HIV treatment and prevention of mother-to-child transmission both require an individualized approach, and all treatment decisions must be based on a full clinical evaluation, including laboratory testing and ongoing monitoring, by a qualified healthcare specialist.