Also called AZT, an HIV medicine
Zidovudine
An HIV medicine used as part of combination treatment, and to help prevent mother-to-baby transmission.
What is Zidovudine?
Zidovudine, also called AZT, is an HIV medicine and one of the first ever developed. It belongs to a group called NRTIs and is used as part of combination treatment for HIV, and also to help prevent HIV being passed from mother to baby. Its most important side effect is suppression of the bone marrow, which can cause anaemia and low white blood cell counts, so blood counts are monitored. Like other medicines in its class, it can also rarely cause serious problems called lactic acidosis and liver trouble. It is always used with other HIV medicines, not alone.
Education and reference only. This is a plain-language guide to Zidovudine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Zidovudine, widely known as AZT, was one of the first medicines developed to treat HIV. It is a type of antiretroviral called a nucleoside reverse transcriptase inhibitor (NRTI). It is taken as part of a combination of HIV medicines, never on its own, because using HIV medicines together keeps the virus under control and prevents resistance. It also has an important role in helping to prevent HIV being passed from a mother to her baby around the time of birth. It is taken by mouth, and sometimes given into a vein in specific situations.
How it works
HIV needs to copy its genetic material to multiply, using an enzyme called reverse transcriptase. Zidovudine looks like one of the building blocks the virus needs, so when the virus tries to use it, the copying process is blocked and the virus cannot reproduce properly. This helps lower the amount of virus in the body. Because the virus can become resistant to a single medicine, zidovudine is always combined with other HIV medicines that attack the virus in different ways. The same actions on fast-dividing cells help explain why it can affect the bone marrow.
Company & origin
Originated / developed by: Generic (long-established).
One of the first HIV medicines, used in the UK as part of combination treatment for HIV and to help prevent passing HIV from mother to baby.
Practical use
How to take Zidovudine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it by mouth as prescribed, as part of your full combination of HIV medicines, at the same times each day.
- Do not miss doses or stop without advice, as this lets the virus become resistant and harder to treat.
- Attend your blood tests, as they check for anaemia and low white blood cells, which this medicine can cause.
- Seek urgent help if you feel very breathless, deeply tired, have bad stomach pain or your skin or eyes turn yellow.
- Tell your team about all your other medicines, as some can add to the effect on the bone marrow.
Weighing it up
Advantages & disadvantages of Zidovudine
Advantages
- An effective part of combination treatment that helps control HIV.
- Has an established role in helping to prevent HIV passing from mother to baby.
- A long-established medicine with decades of experience behind its use.
Disadvantages
- Can suppress the bone marrow, causing anaemia and low white blood cell counts.
- Can rarely cause serious lactic acidosis and liver problems.
- Must always be combined with other HIV medicines and taken consistently to avoid resistance.
Practical use
Good to know
The most important thing to understand about zidovudine is its effect on the bone marrow, where blood cells are made: it can lower red blood cells (causing anaemia and tiredness) and white blood cells (raising infection risk), which is why regular blood counts are part of treatment. Like other medicines in its class, it can rarely cause a serious build-up of acid in the body called lactic acidosis, and liver problems, which need urgent attention if symptoms such as deep tiredness, breathlessness, stomach pain or yellowing of the skin appear. It is always taken as part of a combination of HIV medicines and taken consistently, because missing doses lets the virus become resistant. Beyond treating HIV, it has an established role in helping to prevent a baby catching HIV from its mother. Other effects include nausea, headache and muscle aches.
Who should not take it / use with caution
- People who have had a serious allergic reaction to zidovudine should not take it.
- People with very low blood counts (severe anaemia or low white cells) generally should not take it until this is addressed.
- It is used with care in people with liver problems, and blood counts are watched closely throughout.
Monitoring
- Regular blood counts to check for anaemia and low white blood cells.
- Checking the amount of virus in the blood and how well HIV is controlled.
- Watching liver function and for any signs of lactic acidosis.
Side effects
- Anaemia (low red cells) causing tiredness, and low white blood cells raising infection risk.
- Nausea, headache, muscle aches or difficulty sleeping.
- Changes in body fat or skin and nail colouring with longer use.
- Rarely but seriously, lactic acidosis or liver problems, which need urgent medical attention.
Key interactions
- Other medicines that affect the bone marrow can add to the risk of low blood counts.
- Some other HIV and infection medicines can change its effect, so the specialist team manages the combination.
- Tell your team about everything you take, including over-the-counter and herbal products.
Available as: Capsules, tablets and liquid taken by mouth, and a solution for injection into a vein in specific situations.
Answers
Zidovudine: frequently asked questions
What is zidovudine used for?
It is an HIV medicine used as part of combination treatment to control HIV, and it also has a role in helping to prevent HIV passing from mother to baby.
Why are my blood counts checked?
Zidovudine can suppress the bone marrow, lowering red blood cells (anaemia) and white blood cells, so regular blood tests check for these effects.
Why is it always taken with other HIV medicines?
Using HIV medicines together keeps the virus under control and prevents it becoming resistant, so zidovudine is never used on its own.
What is lactic acidosis?
It is a rare but serious build-up of acid in the body that can happen with this class of medicine; seek urgent help for deep tiredness, breathlessness or stomach pain.
Is it the same as AZT?
Yes, AZT is another name for zidovudine; they are the same medicine, one of the first ever developed to treat HIV.
The wider class
About HIV antiretroviral (NRTI)
Zidovudine belongs to the hiv antiretroviral (nrti) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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