20/01/2026
MECHANISM OF ACTION OF ARVs : HIV Preventive drugs.
Antiretroviral (ARV) drugs work by targeting different steps in the HIV life cycle, preventing the virus from entering cells, replicating its genetic material, and assembling new virus particles, thereby stopping it from multiplying and damaging the immune system. Key mechanisms include blocking viral entry (Entry Inhibitors), stopping reverse transcriptase from converting RNA to DNA (NRTIs, NNRTIs), preventing viral DNA from integrating into host DNA (Integrase Inhibitors), inhibiting protease for new virus maturation (Protease Inhibitors), and disrupting the capsid (Capsid Inhibitors).
Major Classes & Mechanisms:
1.Entry/Fusion Inhibitors:
Block HIV from attaching to or fusing with CD4 cells (host cells).
2.Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTIs/NtRTIs):
Act as "fake" building blocks, stopping the enzyme reverse transcriptase from converting viral RNA into DNA.
3.Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs):
Bind directly to reverse transcriptase, changing its shape and preventing DNA synthesis.
4. Integrase Strand Transfer Inhibitors (INSTIs): Block the viral enzyme integrase, stopping HIV DNA from integrating into the host cell's own DNA.
5. Protease Inhibitors (P*s):
Inhibit the protease enzyme, preventing the cutting of viral proteins needed to form mature, infectious new viruses.
6.Capsid Inhibitors:
Disrupt the viral capsid, a protein shell, preventing proper assembly of new viruses.
By hitting the virus at multiple points (a strategy called Highly Active Antiretroviral Therapy or HAART), these drugs dramatically reduce viral load, allowing the immune system to recover.
