What is HIV and ARV drug treatment?
This is the main type of treatment for HIV or AIDS. It is not a cure, but it can stop people from becoming ill for many years. The treatment consists of drugs that have to be taken every day for the rest of a person's life.
The aim of antiretroviral treatment is to keep the amount of HIV in the body at a low level. This stops HIV's attrition on the immune system and allows it to recover from any damage that HIV might have caused already.
What is combination therapy?
Taking two or more antiretroviral drugs at a time is called combination therapy. Taking a combination of three or more anti-HIV drugs is sometimes referred to as Highly Active Antiretroviral Therapy (HAART).
Why do people need to take more than one drug at a time?
If only one drug was taken, HIV would quickly become resistant to it and the drug would stop working. Taking two or more antiretrovirals at the same time vastly reduces the rate at which resistance develops, making treatment more effective in the long term.
The groups of antiretroviral drugs
There are five groups of antiretroviral drugs. Each of these groups attacks HIV in a different way.
Antiretroviral drug class |
Abbreviations |
First approved to treat HIV |
How they attack HIV |
Nucleoside/Nucleotide Reverse Transcriptase Inhibitors |
NRTIs,
nucleoside analogues,
nukes |
1987 |
NRTIs interfere with the action of an HIV protein called reverse transcriptase, which the virus needs to make new copies of itself. |
Non-Nucleoside Reverse Transcriptase Inhibitors |
NNRTIs,
non-nucleosides,
non-nukes |
1997 |
NNRTIs also stop HIV from replicating within cells by inhibiting the reverse transcriptase protein. |
Protease Inhibitors |
PIs |
1995 |
PIs inhibit protease, which is another protein involved in the HIV replication process. |
Fusion or Entry Inhibitors |
|
2003 |
Fusion or entry inhibitors prevent HIV from binding to or entering human immune cells. |
Integrase Inhibitors |
|
2007 |
Integrase inhibitors interfere with the integrase enzyme, which HIV needs to insert its genetic material into human cells. |
What does combination therapy usually consist of?
The most common drug combination given to those beginning treatment consists of two NRTIs combined with either an NNRTI or a "boosted" protease inhibitor. Ritonavir (in small doses) is most commonly used as the booster; it enhances the effects of other protease inhibitors so they can be given in lower doses. An example of a common antiretroviral combination is the two NRTIs zidovudine (AZT) and lamivudine (3TC), combined with the NNRTI efavirenz (EFV).
First and second line therapy
At the beginning of treatment, the combination of drugs that a person is given is called first line therapy. If after a while HIV becomes resistant to this combination, or if side effects are particularly bad, then a change to second line therapy is usually recommended. Second line therapy will ideally include a minimum of three new drugs, with at least one from a new class, in order to increase the likelihood of treatment success.
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