Discuss the mechanism of action of antiretroviral therapy (ART) in HIV infection and explain why a combination of drugs (HAART) is preferred over a single drug regimen.
Answer
ART targets different stages of the HIV life cycle; nucleoside reverse transcriptase inhibitors (NRTIs) block DNA synthesis, non‑nucleoside reverse transcriptase inhibitors (NNRTIs) bind reverse transcriptase, protease inhibitors prevent viral protein maturation, and integrase inhibitors block integration of viral DNA. Using a combination (HAART) attacks the virus at multiple points, reduces the chance of resistance development, and achieves a more sustained viral load suppression.
Step-by-step solution
- List the major steps in the HIV replication cycle: entry, reverse transcription, integration, transcription/translation, assembly, maturation.
- Describe how NRTIs mimic natural nucleotides and cause chain termination during reverse transcription.
- Explain that NNRTIs bind to a different site on reverse transcriptase, causing conformational change and inhibition.
- State that protease inhibitors block the viral protease needed for processing polyproteins into functional proteins, preventing maturation.
- Mention integrase inhibitors stop integration of viral DNA into host genome.
- Summarize that each drug class targets a distinct stage, so using them together (HAART) reduces viral replication more effectively.
- Explain that HIV mutates rapidly; attacking multiple stages lowers the probability that a single mutation confers resistance to all drugs.
- Conclude that combination therapy leads to durable viral load suppression and improves patient outcomes.
Common mistake: Thinking a single drug can fully suppress HIV without resistance
Concept tested: Mechanism of ART and rationale for HAART
Published · How this solution was prepared and checked
← All Human Health and Disease questions