HIV: Antiretroviral Therapy (ART) - Types, Brand Names, How They Work

Antiretroviral therapy (ART) is the recommended treatment for HIV infection. ART consists of a combination of three or more antiretroviral (ARV) drugs that target different stages of the HIV life cycle. By suppressing viral replication, ART can reduce the amount of HIV in the body (viral load) to undetectable levels, thereby improving the immune system and preventing the development of AIDS-related complications.

There are six main classes of ARV drugs, each with its own unique mechanism of action:

1. Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTIs/NtRTIs):

- Brand names: Zerit (stavudine), Epivir (lamivudine), Retrovir (zidovudine), Videx (didanosine), Intelence (etravirine), Viread (tenofovir disoproxil fumarate)

- Mechanism of action: NRTIs/NtRTIs interfere with the reverse transcription of HIV RNA into viral DNA, an essential step in the virus's replication process.

2. Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIs):

- Brand names: Sustiva (efavirenz), Viramune (nevirapine), Rescriptor (delavirdine), Intelence (etravirine)

- Mechanism of action: NNRTIs bind to the reverse transcriptase enzyme, preventing it from converting HIV RNA into DNA, thereby inhibiting viral replication.

3. Protease Inhibitors (PIs):

- Brand names: Crixivan (indinavir), Norvir (ritonavir), Invirase (saquinavir), Reyataz (atazanavir), Prezista (darunavir), Lexiva (fosamprenavir)

- Mechanism of action: PIs block the protease enzyme, which is necessary for the formation of mature, infectious HIV particles, preventing the spread of the virus.

4. Integrase Strand Transfer Inhibitors (INSTIs):

- Brand names: Isentress (raltegravir), Tivicay (dolutegravir), Biktarvy (bictegravir)

- Mechanism of action: INSTIs inhibit the integrase enzyme, which is responsible for integrating the viral DNA into the host cell's DNA, a crucial step in the HIV replication cycle.

5. Entry Inhibitors/Fusion Inhibitors:

- Brand names: Fuzeon (enfuvirtide), Selzentry (maraviroc), Prezcobix (daraprim)

- Mechanism of action: Entry inhibitors prevent the virus from entering the host cell by blocking the fusion of the viral envelope with the host cell membrane.

6. CCR5 Antagonists:

- Brand name: Selzentry (maraviroc)

- Mechanism of action: CCR5 antagonists block the CCR5 receptor, which is used by some strains of HIV to enter the host cell, preventing the virus from infecting immune cells.

ART regimens typically include a combination of drugs from at least two different classes to reduce the risk of resistance. The choice of drugs depends on various factors such as the patient's viral load, resistance profile, previous treatment history, drug interactions, and side effects.

It's important to note that ART does not cure HIV, but it can effectively suppress the virus and help individuals with HIV live longer, healthier lives. Strict adherence to the medication regimen is essential to maintain viral suppression and prevent drug resistance. Regular monitoring of viral load and CD4 cell counts is crucial for assessing the effectiveness of ART and potential medication adjustments.