Pharmacology · single question
What is the mechanism of action of abacavir?
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Correct answer: B. Nucleoside analogue reverse transcriptase inhibition
- A. Protease inhibition describes ritonavir, atazanavir, and darunavir — a different antiretroviral class that blocks cleavage of viral polyproteins.
- B. CORRECT. Abacavir is a NUCLEOSIDE ANALOGUE REVERSE TRANSCRIPTASE INHIBITOR (NRTI) used in HIV therapy. As a guanosine analogue it is phosphorylated intracellularly and incorporated into viral DNA, where the absence of a 3'-hydroxyl group terminates chain elongation. Its notable hazard is a potentially fatal HYPERSENSITIVITY REACTION linked to HLA-B*57:01, so genotyping is required before initiation.
- C. DNA gyrase inhibition is the mechanism of the FLUOROQUINOLONES (ciprofloxacin, levofloxacin) — antibacterial agents, not antiretrovirals.
- D. Integrase strand-transfer inhibition describes dolutegravir, raltegravir, and bictegravir.