Zidovudine

What is zidovudine?

Zidovudine is a medication used to treat HIV, originally marketed under the brand name Retrovir. Generic versions of zidovudine are now available too. It is taken in combination with other antiretroviral drugs.

The usual adult dose of zidovudine is 250mg twice a day. You should take the two doses 12 hours apart.

Zidovudine is also available in combination tablets. Several companies make a pill which contains zidovudine and another drug, lamivudine, in one pill. This was originally marketed under the brand name Combivir, but generic versions are now available. Zidovudine, lamivudine and abacavir are also available in a combination marketed as Trizivir.

How does zidovudine work?

Zidovudine is from a class of drugs known as nucleoside reverse transcriptase inhibitors (NRTIs). Your doctor will prescribe zidovudine as part of your HIV treatment, along with antiretrovirals from another class of drugs. It is important to take all the drugs as prescribed, every day. Each drug class works against HIV in a different way.

The aim of HIV treatment is to reduce the level of HIV in your body (viral load). Ideally, your viral load should become so low that it is undetectable – usually less than 50 copies of virus per ml of blood. Taking HIV treatment and having an undetectable viral load protects your immune system and stops HIV being passed on to someone else during sex.

How do I take zidovudine?

You can take zidovudine with or without food. You should swallow the capsules whole, with some water.

HIV treatment works best if you take it every day. When would be a good time for you to plan to take your treatment? Think about your daily routine and when you will find it easiest to take your treatment.

If you forget to take a dose of zidovudine, take it as soon as you remember. If it is nearly time for your next dose (within two hours), then don’t take a double dose, just skip the dose you’ve forgotten and carry on.

If you regularly forget to take your treatment, or you aren’t taking it for another reason, it’s important to talk to your doctor about this.

What are the possible side-effects of zidovudine?

All drugs have possible side-effects. It’s a good idea to talk to your doctor about possible side-effects before you start taking a drug. If you experience something that might be a side-effect, talk to your doctor about what can be done. A full list of side-effects, including less common side-effects, should be included in the leaflet that comes in the packaging with zidovudine.

Glossary

antiretroviral (ARV)

A substance that acts against retroviruses such as HIV. There are several classes of antiretrovirals, which are defined by what step of viral replication they target: nucleoside reverse transcriptase inhibitors; non-nucleoside reverse transcriptase inhibitors; protease inhibitors; entry inhibitors; integrase (strand transfer) inhibitors.

drug interaction

When a person is taking more than one drug, and drug A interferes with the functioning of drug B. Blood levels of the drug may be lowered or raised, potentially interfering with effectiveness or making side-effects worse. Also known as a drug-drug interaction.

viral load

Measurement of the amount of virus in a blood sample, reported as number of HIV RNA copies per milliliter of blood plasma. The VL is an important indicator of HIV progression and of how well treatment is working. 

 

undetectable viral load

A level of viral load that is too low to be picked up by the particular viral load test being used or below an agreed threshold (such as 50 copies/ml or 200 copies/ml). An undetectable viral load is the first goal of antiretroviral therapy.

generic

In relation to medicines, a drug manufactured and sold without a brand name, in situations where the original manufacturer’s patent has expired or is not enforced. Generic drugs contain the same active ingredients as branded drugs, and have comparable strength, safety, efficacy and quality.

We generally divide side-effects into two types:

Common – a side-effect that occurs in at least one in a hundred people (more than 1%) who take this drug.

Rare – a side-effect that occurs in fewer than one in a hundred people (less than 1%) who take this drug.

Common side-effects of zidovudine include (most common in bold):

  • headaches, feeling dizzy, aching muscles, and generally feeling unwell.
  • feeling sick (nausea), being sick (vomiting), diarrhoea, stomach pains.

There are also some common side-effects which your doctor will check for with blood tests. These are: low red blood cell count (anaemia) or low white blood cell count (neutropenia or leucopenia); an increase in the level of liver enzymes; an increased amount in the blood of bilirubin, which may make your skin appear yellow.

Treatment with zidovudine can cause body fat loss (lipoatrophy). If you notice any fat loss from your legs, arms or face, tell your doctor, as your treatment should be changed.

Does zidouvudine interact with other drugs?

You should always tell your doctor and pharmacist about any other drugs or medication you are taking. That includes anything prescribed by another doctor, medicines you have bought from a high-street chemist, herbal and alternative treatments, and recreational or party drugs (‘chems’).

Some medicines or drugs are not safe if taken together – the interaction could cause increased, dangerous levels, or it could stop one or both of the drugs from working. Other drug interactions are less dangerous but still need to be taken seriously. If levels of one drug are affected, you may need to change the dose you take. This must only be done on the advice of your HIV doctor.

Any drugs that are known to have interactions with zidovudine will be listed in the leaflet that comes in the packaging with zidovudine. Tell your doctor if you are taking any of these drugs, and other drugs that are not on the list.

You should not take zidovudine with any of these drugs:

  • ganciclovir injections
  • ribavirin
  • rifampicin
  • stavudine

The following drugs interact with zidovudine. They may make it more likely that you will have side-effects, or you may need some extra monitoring, so make sure you tell your doctor if you are taking any of them:

  • aciclovir
  • amphotericin
  • atovaquone
  • clarithromycin
  • cotrimoxazole
  • dapsone
  • doxorubicin
  • fluconazole
  • flucytosine
  • ganciclovir
  • interferon
  • methadone
  • pentamidine
  • phenytoin
  • probenecid
  • pyrimethamine
  • sodium valproate
  • vinblastine
  • vincristine

Can I take zidovudine in pregnancy?

If you are considering having a baby, or think you might be pregnant, talk to your doctor as soon as possible about which combination of anti-HIV medications would be right for you. It is important to take antiretroviral treatment during pregnancy to prevent passing HIV from mother to baby.

The British HIV Association (BHIVA) recommends that women who are already taking anti-HIV medications and become pregnant can usually continue to take the same medication throughout their pregnancy. In addition, BHIVA lists zidovudine (in combination with other medications) as an option that may be considered for women who start HIV treatment in pregnancy, depending on their individual circumstances.

Can children take zidovudine?

Zidovudine is approved for use in children. A liquid formulation is available.

Talking to your doctor

If you have any concerns about your treatment or other aspects of your health, it’s important to talk to your doctor about them.

For example, if you have a symptom or side-effect or if you are having problems taking your treatment every day, it’s important that your doctor knows about this. If you are taking any other medication or recreational drugs, or if you have another medical condition, this is also important for your doctor to know about.

Building a relationship with a doctor may take time. You may feel very comfortable talking to your doctor, but some people find it more difficult, particularly when talking about sex, mental health, or symptoms they find embarrassing. It’s also easy to forget things you wanted to talk about.

Preparing for an appointment can be very helpful. Take some time to think about what you are going to say. You might find it helpful to talk to someone else first, or to make some notes and bring them to your appointment.  

For detailed information on this drug, visit the zidovudine pages in the A-Z of antiretroviral medications.

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