Medicines for HIV and AIDS are used to decrease the amount of HIV in the body and to strengthen the immune system. There are six types of HIV medicines. Commonly three different types of medicines are taken together. This is called combination therapy. It is vital to take them 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.
What are HIV and AIDs?
HIV stands for human immunodeficiency virus. This is a virus in the group of viruses called retroviruses. HIV destroys cells in the body called CD4 T cells. CD4 T cells are a type of white blood cell (lymphocyte). These are important cells that protect the body against various bacteria, viruses and other germs. HIV actually multiplies within CD4 cells. HIV cannot be destroyed by white blood cells, as it keeps on changing its outer coat, so protecting it.
AIDS stands for acquired immunodeficiency syndrome. This is a term which covers the range of infections and illnesses which can result from a weakened immune system caused by HIV.
It is important to remember that when you are first infected with HIV you do not have AIDS. There is usually a time lag of several years between first being infected with HIV and subsequently developing infections and other AIDS-related problems. This is because it usually takes several years for the number of CD4 T cells to reduce to a level where your immune system is weakened. There is no guarantee that you will develop AIDS-related problems, even if you become infected with HIV. Early treatment can reduce the chance of this happening even further.
HIV is now a treatable medical condition and most treated people remain fit and well.
This leaflet is a brief overview of medicines that are used to treat HIV and AIDS. For more information see separate leaflet called HIV and AIDS.
What are medicines for HIV and AIDS and how do they work?
Medicines for HIV and AIDS are sometimes called antiretroviral medicines. There are six different types of these medicines available to prescribe in the UK; they include:
- Nucleoside or nucleotide reverse transcriptase inhibitors - abacavir, didanosine, emtricitabine, lamivudine, stavudine and tenofovir.
- Non-nucleoside reverse transcriptase inhibitors - efavirenz, etravirine, nevirapine and rilpivirine.
- Protease inhibitors - atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, ritonavir, saquinavir and tipranavir.
- Integrase inhibitors - raltegravir.
- Fusion inhibitors - enfuvirtide.
- CCR5 antagonists - maraviroc.
There is also a medicine called cobicistat which increases the action of antiretrovirals but does not have any effect on the virus itself.
Antiretroviral medicines work by stopping the HIV from making copies of itself. The amount of virus in your body (viral load) is decreased. This gives your immune system some time to become strong again and allows your body to make more CD4 T cells. The aim of treatment is to reduce the viral load to very low levels for as long as possible and to increase the number of CD4 T cells to a normal level. This in turn means you are less likely to get infections.
The medicines in each class work in slightly different ways but all work to stop the HIV from copying (replicating) itself. They work best when they are prescribed in combination.
If I have HIV or AIDS when is treatment usually started?
As a general rule, antiretroviral medicines are usually started:
- Immediately after diagnosis of HIV infection;
- When infections or other AIDS-related problems develop; if your CD4 T cells fall below a certain level (around 200 cells per cubic millimetre of blood or less) - and you have a serious bacterial infection or an AIDS-defining infection. The exact level when treatment is started depends on various factors which your doctor will discuss with you. These include any symptoms present and the rate of decline of the CD4 T cells.
The treatment of HIV is a rapidly changing area of medicine. Trials are underway to assess whether antiretroviral medicines should be started earlier in people who have no symptoms, even as early as when first infected with HIV. The trials aim to show whether there are benefits from treatment before symptoms develop, which outweigh the risk of side-effects from the medicines.
Which antiretrovirals are usually prescribed?
The choice of medicines is considered and chosen for each individual patient. The treatment for HIV can be complicated, as it involves taking many different medications. A team of healthcare professionals is usually involved in looking after you and giving you your treatment.
As discussed above, these medicines work best in combination. Taking three or more antiretroviral medicines at the same time, each attacking HIV at different points in its cycle of copying (replication), is more effective than one or two medicines alone. Taking a combination of different medicines also reduces the risk that the virus will become resistant to any individual medicine. In 2008, the first one pill a day treatment was launched. Each pill contains three different medicines. This is popular, as it is convenient to take and has few side-effects.
Guidelines suggest that people who have never taken antiretrovirals before should start with two nucleoside reverse transcriptase inhibitors (NRTIs) plus one of a protease inhibitor, a non-nucleoside reverse transcriptase inhibitor or an integrase inhibitor.
When taking medicines for HIV and AIDS
Some important considerations are:
- Adherence - taking your medicines exactly as prescribed.
- What to do if you miss a dose.
- Dietary restrictions.
- Regular blood tests.
- Taking other medicines.
Adherence - taking your medicines exactly as prescribed
It is vital to take the medication regularly and exactly as prescribed, to maintain success and to help to prevent the virus from becoming resistant to the medicines. Even if you miss one or two doses, the virus can become resistant to treatment.
What to do if you miss a dose
If you forget to take a dose, take your medicines as soon as you remember. However, if you remember just as you are about to take your next dose, do not take two doses at the same time to make up for the missed dose. If in doubt, speak with your pharmacist or doctor.
If you are regularly forgetting to take your medicine, talk with your doctor or pharmacist; there may be other combination medicines that are more suitable for you.
Regular blood tests
You are likely to have regular blood tests to monitor how well these medicines are working. You will usually have a CD4 T-cell count and a viral load blood test before you start treatment. This is called a baseline measurement. After starting treatment, your doctor will usually measure your viral load and CD4 T-cell count after one month and then about every three months thereafter. If your treatment is effective then your viral load will decrease and your CD4 T cells will increase.
You may need more blood tests if you feel unwell or develop symptoms such as an infection.
Taking other medicines
Quite a few medicines that you may be prescribed for other conditions or that you can buy from pharmacies or supermarkets can interfere with HIV medicines. This includes herbal medicines. Always ask your pharmacist or doctor before taking any new medicines. For more information see the leaflet that came with your medicine.
What are the possible side-effects?
The side-effects for most HIV medicines are usually mild and often go away after a few weeks. Common side-effects include feeling sick (nausea), being sick (vomiting) and headache. If these side-effects do not go away, your doctor can prescribe some other medicines to help with these problems. If this does not help, your doctor may change your medicines.
Other less common side-effects include:
- Damage to the liver, kidneys or pancreas.
- Skin rash.
- Dry skin, nail problems, hair loss.
- Damage to the nerves (peripheral neuropathy).
- Fat loss (lipoatrophy).
- Fat accumulation.
- Increased blood-sugar levels and risk of type 2 diabetes.
See the leaflet that comes with your particular brand for a full list of possible side-effects and cautions.
What is the usual length of treatment?
Once you have started treatment you will need to take these medicines for the rest of your life. This is in order to keep your immune system healthy and to prevent you from getting infections.
How well do medicines for HIV and AIDS work?
Although these medicines do not cure HIV, they slow the progression of HIV to AIDS. They are effective at allowing people with HIV to live their lives as normally as possible. Since the introduction of medicines to treat HIV, the death rates from AIDS have reduced dramatically. Newer medicines are more effective than medicines used in the past.
What happens if I do not take HIV medicines?
If you have HIV and do not take HIV medicines, eventually - typically, over a number of years - your viral load increases and the number of CD4 T cells decreases significantly. Your immune system becomes very weak. This means that you are open to getting infections and your body is unable to fight the infection. These infections can become serious and overwhelming for your body and you are likely to die.
How to use the Yellow Card Scheme
If you think you have had a side-effect to one of your medicines you can report this on the Yellow Card Scheme. You can do this online at the following web address: www.mhra.gov.uk/yellowcard.
The Yellow Card Scheme is used to make pharmacists, doctors and nurses aware of any new side-effects that medicines or any other healthcare products may have caused. If you wish to report a side-effect, you will need to provide basic information about:
- The side-effect.
- The name of the medicine which you think caused it.
- The person who had the side-effect.
- Your contact details as the reporter of the side-effect.
It is helpful if you have your medication - and/or the leaflet that came with it - with you while you fill out the report.
Dr Laurence Knott
Dr John Cox