Antiretroviral drugs work by keeping HIV from multiplying. There are five kinds of antiretroviral drugs approved by the US Food and Drug Administration, which attack four different phases of the HIV reproductive cycle (Department of Health and Human Services [DHHS], 2005).
Current antiretroviral HIV medications fall into five classes:
- Entry inhibitors
- Nucleoside reverse transcriptase inhibitors (NRTIs)
- Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
- Integrase inhibitors
- Protease inhibitors
Here is how each class of HIV antiretroviral drug works:
- Entry Inhibitors: To make copies of itself, HIV first uses its spikes to fuse with the host cell’s membrane, and then thrusts its contents inside. Entry inhibitors work to prevent HIV from entering the cell.
- Nucleoside Reverse Transcriptase Inhibitors (NRTIs): To make copies of itself, HIV uses an enzyme called reverse transcriptase to convert its RNA into DNA after the virus enters the host cell. NRTIs are faulty versions of molecules used to build a DNA chain. When the HIV attempts to turn its RNA into DNA, NRTIs cause the DNA chain to be incomplete, resulting in DNA that cannot create new copies of the virus
- Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs): Like NRTIs, NNRTIs also interfere with reverse transcriptase. NNRTIs chemically bind to reverse transcriptase and make it unable to do its job
- Integrase Inhibitors: Once the new DNA chain is finished, it enters the host cell's nucleus and splices itself into the host cell’s DNA using an enzyme called integrase. Integrase inhibitors chemically bind to integrase and stop it from working, so the virus's DNA is not incorporated into the host cell's DNA
- Protease Inhibitors (PIs): After HIV hijacks a cell's nucleus to make copies of itself, it needs an enzyme called protease to chop its long chains of proteins into infectious bits. Protease inhibitors chemically bind to protease, so that protease cannot cleave the HIV proteins into mature viral particles
Discussion question: How do each of the anti-HIV medication types: NRTIs, NNRTIs, PIs, entry inhibitors (fusion inhibitors/coreceptor blockers), and integrase inhibitors, work to fight HIV?
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