Antiretroviral therapy (ART)
Antiretroviral therapy (ART) is the treatment for HIV infection. It involves taking a combination of medicines every day. ART is recommended for everyone with HIV, regardless of their CD4 count or viral load.
ART does not cure HIV infection, but it can help people with HIV live long, healthy lives. It can also reduce the risk of spreading HIV to others.
HIV medicines work by reducing the amount of HIV (viral load) in the body. This helps people with HIV in two ways:
- It gives the immune system a chance to recover. HIV attacks and destroys the body's CD4 cells, which are an important part of the immune system. When there is less HIV in the body, the immune system has a better chance to recover and produce more CD4 cells. This can help people with HIV fight off infections and certain HIV-related cancers(HIV Medicines, n.d.).
- It reduces the risk of spreading HIV to others. When the viral load is low, it is very unlikely that HIV can be transmitted through sex or sharing needles. This is because there is less virus in the body to be passed on to others.
FDA-Approved HIV Medicines (NIH, 2021):
- Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
- Nucleoside reverse transcriptase inhibitors (NRTIs) are a class of antiretroviral drugs that block reverse transcriptase, an enzyme HIV needs to make copies of itself.NRTIs are similar to the building blocks of DNA. When HIV reverse transcriptase incorporates an NRTI into the DNA that it is making, the NRTI stops the DNA from being completed. This prevents HIV from making copies of itself.
- Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
- Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are a class of antiretroviral drugs that work by binding to and altering the reverse transcriptase enzyme. Reverse transcriptase is an enzyme that HIV needs to make copies of itself. When NNRTIs bind to reverse transcriptase, they prevent the enzyme from working correctly. This prevents HIV from making copies of itself and helps to control the infection.
- Protease Inhibitors (PIs)
- Protease inhibitors (PIs) are a class of antiretroviral drugs that block protease, an enzyme HIV needs to make copies of itself. Protease is responsible for cutting up the HIV protein into smaller pieces that can then be assembled into new viruses. When PIs block protease, they prevent new HIV from being made(Protease Inhibitor (PI) | NIH, n.d.).
- Fusion Inhibitors
- Fusion inhibitors are a class of antiretroviral drugs that work by blocking the fusion of the HIV envelope with the host CD4 cell membrane. This prevents HIV from entering the CD4 cell. Fusion inhibitors work by binding to the HIV envelope protein gp41. GP41 is a protein that is essential for HIV to fuse with the CD4 cell membrane. When fusion inhibitors bind to gp41, they prevent the protein from changing shape, which is necessary for fusion to occur.
- CCR5 Antagonists
- CCR5 antagonists are a class of antiretroviral drugs that work by blocking the CCR5 coreceptor on the surface of certain immune cells. HIV needs to bind to the CCR5 coreceptor in order to enter the cell, so by blocking CCR5, CCR5 antagonists can prevent HIV from infecting the cell.
- Integrase Strand Transfer Inhibitor (INSTIs)
- Integrase inhibitors are a class of antiretroviral drugs that work by blocking HIV integrase, an enzyme that HIV needs to make copies of itself. Integrase is responsible for inserting the HIV genetic material into the DNA of the host cell. By blocking integrase, integrase inhibitors can prevent HIV from infecting the cell and making copies of itself.
- Attachment Inhibitors
- Attachment inhibitors are a class of antiretroviral drugs that work by binding to the gp120 protein on the outer surface of HIV. The gp120 protein is essential for HIV to bind to CD4 cells, so by binding to gp120, attachment inhibitors can prevent HIV from entering CD4 cells.
- Protease inhibitors (PIs) are a class of antiretroviral drugs that block protease, an enzyme HIV needs to make copies of itself. Protease is responsible for cutting up the HIV protein into smaller pieces that can then be assembled into new viruses. When PIs block protease, they prevent new HIV from being made(Protease Inhibitor (PI) | NIH, n.d.).
- Fusion inhibitors are a class of antiretroviral drugs that work by blocking the fusion of the HIV envelope with the host CD4 cell membrane. This prevents HIV from entering the CD4 cell. Fusion inhibitors work by binding to the HIV envelope protein gp41. GP41 is a protein that is essential for HIV to fuse with the CD4 cell membrane. When fusion inhibitors bind to gp41, they prevent the protein from changing shape, which is necessary for fusion to occur.
- CCR5 antagonists are a class of antiretroviral drugs that work by blocking the CCR5 coreceptor on the surface of certain immune cells. HIV needs to bind to the CCR5 coreceptor in order to enter the cell, so by blocking CCR5, CCR5 antagonists can prevent HIV from infecting the cell.
- Integrase inhibitors are a class of antiretroviral drugs that work by blocking HIV integrase, an enzyme that HIV needs to make copies of itself. Integrase is responsible for inserting the HIV genetic material into the DNA of the host cell. By blocking integrase, integrase inhibitors can prevent HIV from infecting the cell and making copies of itself.
- Attachment inhibitors are a class of antiretroviral drugs that work by binding to the gp120 protein on the outer surface of HIV. The gp120 protein is essential for HIV to bind to CD4 cells, so by binding to gp120, attachment inhibitors can prevent HIV from entering CD4 cells.
- Post-Attachment Inhibitors
- The gp120 protein is essential for HIV to bind to CD4 cells. When attachment inhibitors bind to gp120, they prevent HIV from binding to CD4 cells and entering the cell. This prevents HIV from infecting the cell and replicating.
- Capsid Inhibitors
- The capsid is essential for HIV to replicate. When capsid inhibitors bind to the capsid, they interfere with its ability to protect HIV's genetic material and enzymes. This can prevent HIV from replicating and can help to control the infection.
- The gp120 protein is essential for HIV to bind to CD4 cells. When attachment inhibitors bind to gp120, they prevent HIV from binding to CD4 cells and entering the cell. This prevents HIV from infecting the cell and replicating.
- Capsid Inhibitors
- The capsid is essential for HIV to replicate. When capsid inhibitors bind to the capsid, they interfere with its ability to protect HIV's genetic material and enzymes. This can prevent HIV from replicating and can help to control the infection.
Pharmacokinetic Enhancers
PKEs work by slowing down the breakdown of HIV medicine in the body. This allows more of the medicine to reach the bloodstream and be effective in fighting HIV.
Resources
Abacavir - Patient | NIH. (n.d.). Clinicalinfo.hiv.gov. https://clinicalinfo.hiv.gov/en/drugs/abacavir/patient
HIV Medicines. (n.d.). Medlineplus.gov. https://medlineplus.gov/hivmedicines.html
NIH. (2021, February 8). FDA-Approved HIV Medicines | HIVINFO. Hivinfo.nih.gov. https://hivinfo.nih.gov/understanding-hiv/fact-sheets/fda-approved-hiv-medicines
Protease Inhibitor (PI) | NIH. (n.d.). Clinicalinfo.hiv.gov. https://clinicalinfo.hiv.gov/en/glossary/protease-inhibitor-pi
