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Knowing About HIV Treatment
What I should know about ARV treatment?
YOU SHOULD KNOW
What are Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTIs)?
Nucleoside analogue Reverse Transcriptase Inhibitors (NRTIs). NRTIs were the first antiretroviral drugs to be developed. They block the replication of HIV in the early stage by inhibiting Protease enzyme (which is necessary for viral replication) called Reverse Transcriptase.
When HIV infects a cell in a person's body, it copies its own genetic code into the cell's DNA. In this way, the cell is then "programmed" to create new copies of HIV. HIV's genetic material is in the form of RNA. In order for it to infect T-cells, it must first convert its RNA into DNA. HIV's reverse transcriptase enzyme is needed to perform this process.
NRTIs contain faulty versions of the building blocks (nucleotides) used by reverse transcriptase to convert RNA to DNA. When reverse transcriptase uses these faulty building blocks, the new DNA cannot be built correctly. In turn, HIV's genetic material cannot be incorporated into the healthy genetic material of the cell and prevents the cell from producing new virus.
Thus, when an NRTI is incorporated, viral DNA synthesis is halted, a process known as chain termination.
What are Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)?
NNRTIs are a class of anti-HIV drugs. When one NNRTI is used in combination with other anti-HIV drugs – usually a total of 3 drugs – then this combination therapy can block the replication of HIV in a person's blood by binding directly to the Protease enzyme.
In contrast, NNRTIs have a completely different mode of action. NNRTIs block reverse transcriptase by binding at a different site on the Protease enzyme.
What are Protease Inhibitors?
Once HIV infects a human cell, the virus uses proteins and chemicals inside that cell to make more copies of itself. Protease is a chemical, known as an enzyme, which HIV needs in order to make new viruses. Protease inhibitors (PIs) block the protease enzyme. When protease is blocked, HIV makes copies of itself that can't infect new cells.
However, studies have also shown that these effects can wear off over time. This happens because HIV makes more of itself all the time. Each new HIV virus that gets made may be slightly different than the one it made before. The new protease that the virus has made may resist the drugs that worked for viruses with the older type of protease. This is what scientists call Drug Resistance. When this happens, other protease inhibitors usually become less effective as well.
What is HAART?
The best way to avoid drug resistance is to stop or reduce HIV production in the body. The less HIV made in the body, the less chance of a virus created that's resistant to anti-HIV drugs. To keep HIV levels as low as possible, it's recommended that protease inhibitors be taken in combination with at least two other anti-HIV drugs. This is called Highly Active Anti-Retroviral Therapy or HAART. Studies have shown that when certain protease inhibitors are combined, the anti-HIV effect is increased, which can help prevent or overcome resistance. This is called Protease Boosting. Some doctors will order a drug resistance test to determine a patient's resistance profile, in order to decide the best drug combination to use.
ARVs reduce a person’s viral load. This means that they reduce the number of viruses in their body.
ARVs lower the ability of HIV to damage the immune system (the body’s natural defence). It means that the immune system can recover its ability to defend a person from attack by other infections, enabling them to stay healthy and live longer.
ARV treatment must be taken for life. If not, the virus will start to reproduce again and will cause AIDS
What difference does ARV treatment make?
ARVs can bring a person with AIDS back to good health and keep a person with HIV healthy.
A person who takes ARVs can live a much longer and healthier life than someone who does not.
What types of ARV treatment are there and how are they combined?
There are three main types of ARV drugs to treat people with HIV. Each one attacks the virus in a different way.
ARVs work best when different types are used together and when at least three different drugs are used. This is known as combination therapy or highly active antiretroviral therapy (HAART). Using just one or two ARVs for long-term treatment is not usually effective.
To prevent mother-to-child transmission (PMTCT) of HIV, just one or two types of ARVs can be used for a short time. This protects the baby from becoming infected by its mother’s virus during birth. It does not affect the woman’s own level of HIV.
ARV treatment can be given to HIV-positive adults or children.
The ARVs that are commonly used are listed below. Those marked with * are recommended by the World Health Organisation in their ARV treatment guidelines. Research continues to try to find new and better drugs for ARV treatment.
| Types of ARVs | Names of drugs |
|---|---|
| Nucleoside/Nucleotide analogues also called Nucleoside/ Nucleotide Reverse Transcriptase Inhibitors (NRTIs) | Abacavir (ABC)* Didanosine (ddI)* Lamivudine (3TC)* Stavudine (d4T)* Tenofovir* Zidovudine (AZT)* Zalcitabine (ddC) |
| Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIs) | Delavirdine (DLV) Efavirenz (EFV)* Nevirapine (NVP)* |
| Protease Inhibitors (PIs) | Amprenavir Indinavir (IDV)* Lopinavir (LPV)* Nelfinavir (NFV)* Ritonavir (r)* Saquinavir (SQV)* |
When does a person need ARV treatment?
ARV treatment usually starts only when HIV has damaged a person’s immune system.
A doctor can find out what is happening to the immune system of a person with HIV by carefully examining them and checking for any illnesses or problems.
Special blood tests can be used. Depending on the level of resources, these include:
- Tests for anaemia and white blood cells.
- A CD4 test. This shows how much damage HIV has done to the immune system and guides the doctor about when to start treatment.
- A viral load test. This shows how much HIV virus is in the body.
How is ARV treatment used?
ARV medicine are usually tablets, capsules or, sometimes, liquids. These are taken by mouth.
Some ARVs must be taken when the stomach is empty, but others only after eating some food.
ARVs must be taken at specific times each day. This is because the amount of drug in the body must remain at the same level all of the time.
ARVs do not cure HIV. So, treatment must continue every day for the rest of a person’s life – this is called adherence to treatment. Prevention must also continue every day for the rest of a person’s life.
This is a big commitment. So, a person with HIV and their doctor must work together to identify which drugs fit in best with their life. They must also make sure that the person’s condition is regularly monitored - to check if the treatment is working and that any side effects are managed properly.
What is adherence to ARV treatment?
Adherence means taking doses of drugs and sticking to the treatment plan exactly as prescribed. It means taking the correct amount of drugs, at the correct time and in the correct way.
At least 95% adherence is needed for ARVs to work effectively. Missing even a few doses can cause treatment to fail, opportunistic infections (OIs) or drug resistance to start.
Adherence is especially difficult if people are isolated, depressed, forgetful or worrying too much about the effects of their medication.
A person with HIV should work with their doctor, pharmacist and treatment supporters to find ways to help with adherence. These might include: getting support from family and friends; having regular check ups; getting prompt help with side effects; and being able to talk to others who take ARVs.
What are the side effects of ARVs?
Side effects are the unintended effects of a drug.
Different ARVs cause different side effects. Not all of them are experienced by all people.
Some side effects – usually nausea, diarrhoea or tiredness – may appear soon after a person starts taking ARVs. However, they often do not last long and treatment can continue without problems.
Other ARV side effects include skin rash, dry skin, chapped lips, insomnia, sexual problems, mood changes and difficulties in moving or walking.
Some long-term side effects can be very serious. They may appear mild at first, but can indicate major problems. These include peripheral neuropathy, liver damage and lipodystrophy.
It is vital to ensure a person knows about possible side effects before he or she starts to take ARVs.
There are many different ways to manage side effects. However, if they are severe, a person’s doctor might decide to change their treatment.
Can a person use alcohol, tobacco or other drugs when taking ARV treatment?
ARVs and many other substances affect each other in different ways. These include prescription drugs, other medicines (cough remedies, pain killers, vitamins), alcohol, tobacco, marijuana, cocaine, and narcotics.
A person who is prescribed ARVs must tell their doctor or pharmacist what else they are taking.
Some substances will have no effect on a person’s ARV treatment, but others might change the effectiveness of the drugs. A person might have to change or stop using substances that interfere with ARVs, especially if the liver is not working well.
Is drug resistance a problem with ARV treatment?
Drug resistance happens when the HIV virus changes so that a particular drug cannot attack it.
When this happens, ARVs can become ineffective; then a person’s viral load increases and the immune system starts to get damaged again.
Drug resistance happens much more easily if a few ARV doses are missed or taken at the wrong time.
If a person’s treatment fails, the doctor will try to change to a different type of HAART. This might mean having more complicated & expensive treatment with up to 4 or 5 drugs.
A person with drug-resistant HIV can pass it on to others, meaning they too will need special HAART.
ARVs enable a person with HIV to have a better and longer life. But they do not cure a person of HIV.
ARVs must be taken continuously and correctly for the whole lifetime of a person with HIV.
Even if a person is taking ARVs and has a very low viral load, they can still infect other people with HIV.
Research courtesy the International HIV AIDS Alliance
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