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Monitoring and switching antiretroviral treatment for HIV

Monitoring and switching treatment


  • Antiretroviral treatment (ART) protects the immune system, but only if it is taken consistently as prescribed – this usually means every day at roughly the same time.
  • Some people experience side effects initially, but these usually go away. If they remain you may be able to switch ARV treatment (to a different combination of drugs).
  • Regular blood tests, which measure the levels of virus in your body (viral load) or the strength of your immune system (CD4 count), will show if your treatment is working.
  • If your treatment stops working, your healthcare professional will advise you on changing to different drugs. 

Once you start taking HIV treatment, it’s important that you take it every day. Your healthcare professional will explain how many pills to take, how often to take them, and whether you should take them with food.

HIV treatment can only work if you always take it properly. If you have problems taking it, or you have questions or concerns about your treatment or health, it’s really important to tell your healthcare professional.

How can I tell if my treatment is working?

Having regular blood tests will show how well your treatment is working. If you were ill because of HIV, treatment should also mean you start to feel better.

The CD4 count is a blood test which shows the strength of your immune system. When you start taking treatment your CD4 count will go up.

The other test used to monitor HIV is called the viral load. This is also a blood test, and it gives an indication of the level of HIV in your body. The aim of HIV treatment is to lower your viral load and then to keep it as low as possible.

WHO recommends that you have a viral load test six months after you start taking treatment, and then once a year.1 This will show whether your treatment is working (keeping your viral load low) or not (your viral load has stayed high or is going up). In some countries, viral load testing is not available. If this is the case where you are, your healthcare professional will monitor your health and your CD4 count in other ways.

When your viral load is very low, it may not be possible for tests to measure it. This is a really good result and is called an undetectable viral load. You still have HIV, but it is being kept under control by the HIV treatment.

Keeping your viral load low prevents damage to your immune system and if your CD4 count was low when you started treatment, it should increase over time.

Does it matter if I sometimes forget to take my treatment?

Yes. Current HIV treatment is designed to be taken every single day. The drugs keep HIV under control but they don’t stay in your body for a long time, so you have to keep topping them up.

If you stop taking your HIV drugs, then your viral load will go up. This means HIV can damage your immune system, and that you are more likely to pass HIV on.

If you regularly miss doses of your HIV treatment, there is a risk that the HIV in your body will become resistant to the drugs you are taking.2 This means that the drugs will no longer work even when you do take them.

For this reason, it is very important that you take your treatment every day. Think about things that might help you to remember your treatment. Some people find it helpful to take their treatment when they go to bed, or with breakfast – something that is part of their daily routine.3

If you know something is going to disrupt your routine – for example if you are going to be staying away from home – then think about what you can do to keep taking your treatment on time. Some people find it helpful to set an alarm, or schedule a reminder on their phone.

Remember that if you are taking a long flight and travelling across time zones, this will have implications for the time you take your medication. 4

Most people forget to take their treatment once in a while.5 However, if you find you often forget, then talk to your healthcare professional about it. It is better that they know you are having problems and can offer you support and advice before your treatment stops working.

My treatment has side-effects. What can I do?

Many people experience some mild side-effects, particularly in the first few days and weeks of starting treatment. For example, you might feel sick or have a headache, but you may feel able to manage these symptoms. The commonly used drug, EFV (efavirenz), often causes strange dreams in the first few weeks of taking it. Although unpleasant, these side-effects should improve and go away altogether as your body gets used to taking the drug.

Some side-effects may be less obvious to you. For example, the commonly used drug TDF (tenofovir) can cause problems with the kidneys.6 Your healthcare professional will check a sample of your urine to look out for early signs of kidney problems.

If you think you are experiencing a side-effect, the best thing you can do is talk to a healthcare professional about it. They can advise you on the best course of action, which may include prescribing something for you to take for a short period, such as an anti-nausea drug. If a side-effect doesn’t go away and is affecting your quality of life, you should be able to change to a different drug.7

What happens if my treatment stops working?

For many people, the treatment they start taking will continue to work for as long as they take it.

If your viral load is not being kept under control by the treatment you are taking, your healthcare professional will want to find out why.8 If you are having problems taking it, or if you are taking another drug which is preventing your HIV treatment from working, then you may be able to resolve these problems and stay on the same treatment.

However, if your treatment has stopped working, perhaps because of drug resistance, then your healthcare professional will advise you to change treatment. There are a number of HIV drugs, so even if you develop drug resistance to one drug, you should be able to change to another drug which is still effective. This is known as second-line therapy.

Photo credit: © Photos are used for illustrative purposes. They do not imply any health status or behaviour on the part of the people in the photo.

Last full review: 
01 May 2015
Next full review: 
01 May 2018
Last updated:
13 August 2018
Last full review:
01 May 2015
Next full review:
01 May 2018