Zidovudine for HIV

About zidovudine

Zidovudine is an antiretroviral medicine. It is prescribed for human immunodeficiency virus (HIV) infection. It slows the progress of HIV infection, but it is not a cure. HIV destroys cells in the body, called CD4 T cells. These cells are a type of white blood cell and are important because they are involved in protecting your body from infection. If left untreated, the HIV infection weakens your immune system so that your body cannot defend itself against bacteria, viruses and other germs. Zidovudine slows down the progress of HIV infection by reducing the amount of virus in your body. It does this by stopping the virus from copying (replicating) itself.

Zidovudine will be prescribed for you by a doctor who is a specialist. It belongs to a group of antiretroviral medicines known as nucleoside reverse transcriptase inhibitors (NRTIs). It is given alongside a number of other antiretroviral medicines, as part of a combination therapy. Taking three or more antiretroviral medicines at the same time is more effective than taking one alone. Taking a combination of different medicines also reduces the risk that the virus will become resistant to any individual medicine. Some brands of zidovudine contain one or more other antiretroviral medicines (see the list in the table above) - these combination brands help to reduce the total number of tablets you need to take each day. Not all of the information in this leaflet applies to the combination brands, so please refer to the manufacturer's printed information leaflet from inside the pack for full details. It is vital to take your antiretroviral medicines exactly as prescribed to maintain success and to help to prevent the virus from becoming resistant to the medicines. These medicines are usually taken for life.

Zidovudine is also prescribed to help prevent passing HIV on to an unborn baby. When it is prescribed for this reason, it can be used alone, or alongside other medicines. After the birth, it may be given to your newborn to help prevent your baby from getting infected with HIV.

Before taking zidovudine

Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking zidovudine it is important that your doctor knows:

• If you are pregnant, trying for a baby or breastfeeding.

• If you have any problems with the way your liver works, or if you have problems with the way your kidneys work.

• If you drink a lot of alcohol.

• If you have been told you have low levels of vitamin B12 in your body, such as if you have pernicious anaemia.

• If you know you have a very low white blood cell count (called neutropenia), or low haemoglobin levels.

• If you have a rare inherited blood disorder called porphyria.

• If you are taking any other medicines. This includes any medicines which are available to buy without a prescription, as well as herbal and complementary medicines.

• If you have ever had an allergic reaction to a medicine.
  

How to take zidovudine

• Before you start the treatment, read the manufacturer's printed information leaflet from inside your pack. It will give you more information about zidovudine, and it will also provide you with a full list of the side-effects which you could experience from taking it.

• Take zidovudine exactly as your doctor tells you to. You will be asked to take two doses each day - take the doses 12 hours apart. Zidovudine is available both as capsules and as a liquid medicine. Adults will usually be prescribed capsules to take, whereas young children are likely to be supplied with the liquid medicine (Retrovir® Oral Solution). Your doctor will advise you about how many capsules or how much of the liquid medicine you (or your child) should take for each dose. The directions will also be printed on the label of the pack to remind you about what the doctor said to you.

• Try to take zidovudine at the same times each day, as this will help you to remember to take it regularly. You can take zidovudine either with or without food. Swallow the capsule whole with a drink of water.

• If you forget to take a dose, take it as soon as you remember. However, if it is within two hours of your next dose when you remember, leave out the missed dose but remember to take the next dose when it is due. Do not take two doses together to make up for a forgotten dose.

Instructions for using the dosing syringe with Retrovir® Oral Solution

1. Remove the bottle cap, and push the plastic adaptor into the top of the open bottle.

2. Make sure the plunger of the syringe is pushed in fully, then insert the tip of the syringe into the adapter.

3. Turn the bottle (with the syringe connected to it) upside down.

4. Gently pull out the plunger of the syringe so that the solution fills the syringe to the mark which corresponds to your dose.

5. Turn the bottle the correct way up again, and remove the syringe from the bottle.

6. Put the tip of the syringe into your child's mouth (or if appropriate, your mouth) and gently push the plunger so that the liquid is released.

7. Repeat steps 2-6 if you have been told to use more than one syringeful.

8. Remove the adaptor from the bottle and replace the bottle cap. Wash the syringe and adaptor with water after each use.

Getting the most from your treatment

• Keep your regular appointments with your doctor so that your progress can be monitored. You will need to have regular blood tests to check how well your medicines are working.

• It is important that you continue to take zidovudine and your other antiretroviral treatment regularly. This will help to prevent the HIV from becoming resistant to the medicines you are taking. Even if you miss only a small number of doses, the virus can become resistant to treatment.

• If you develop an infection soon after you start the treatment, let your doctor know. As a result of taking zidovudine, your immune system may start fighting an infection which was present before you started the treatment, but which you may not have been aware of.

• Follow carefully any advice your doctor gives to you about making lifestyle changes to reduce any risk of damage to your heart and blood vessels. These can include stopping smoking, eating healthily and taking regular exercise.

• Some people taking antiretroviral medicines develop changes to the way body fat is distributed in the body. This can result in changes to body image. Your doctor will discuss the possibility of this with you.

• Although treatment with antiretroviral medicines may reduce the risk of you passing HIV to others through sexual contact, it does not stop it. It is important that you use condoms.

• It is not uncommon for people with HIV to feel low or even depressed, especially soon after the diagnosis has been made and treatment has been started. If you have any feelings of depression, or any distressing thoughts about harming yourself then you should speak with your doctor straightaway.

• Zidovudine has been associated with a serious side-effect in some people who have taken it. This is known as lactic acidosis. It is a problem where there is too much lactic acid in the blood. The symptoms associated with it are listed in the next section 'Can zidovudine cause problems?'. If you develop any of the symptoms listed below, you must let your doctor know straightaway, as they can worsen, and may even become life-threatening.

• Some people who have taken antiretroviral medicines (particularly over a long time) have developed a condition called osteonecrosis. This is a bone disease where bone tissue dies because there is a reduced blood supply to it. It leads to joint pains and stiffness, and can cause difficulties in movement. If you notice any of these symptoms, speak with your doctor.

• If you buy any medicines, supplements or herbal remedies 'over the counter', check with a pharmacist that they are suitable to take with zidovudine and your other medicines. This is because some medicines interfere with antiretrovirals and can stop them from working properly.

• If you are having an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.

• Treatment for HIV is usually lifelong. Continue to take zidovudine regularly for as long as your doctor tells you to, even if you feel well. This is to keep your immune system healthy.

Can zidovudine cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with zidovudine. You will find a full list in the manufacturer's information leaflet supplied with your medicine. You should, however, speak with your doctor if you develop any of the following side-effects. This is because some of the common side-effects of zidovudine are similar to the symptoms of lactic acidosis - a less common but more serious problem.

Your doctor will discuss with you the possibility of lactic acidosis occurring. Let your doctor know straightaway if you develop any of the following symptoms:

• Feeling sick (nausea) or being sick (vomiting), tummy pain, loss of appetite, loss of weight, feeling weak or dizzy, and fast or gasping breathing.

If you experience any other symptoms which you think may be due to the medicine, speak with your doctor or pharmacist for further advice.

How to store zidovudine

• Keep all medicines out of the reach and sight of children.

• Store in a cool, dry place, away from direct heat and light.

• Once a bottle of Retrovir® Oral Solution has been opened it will keep for 30 days - after this time, make sure you have a fresh supply.

Important information about all medicines