Oseltamivir started within 48 hours of symptom onset reduces the duration of influenza illness. Its mechanism of action is:
- A Inhibiting neuraminidase, preventing cleavage of sialic acid and release of progeny virions ✓
- B Blocking the M2 ion channel, preventing uncoating of the virion
- C Inhibiting the cap-snatching endonuclease of the PB1 subunit
- D Binding hemagglutinin and preventing attachment to sialic acid receptors
Correct answer: A. Inhibiting neuraminidase, preventing cleavage of sialic acid and release of progeny virions
Explanation
Neuraminidase on the influenza envelope cleaves terminal sialic acid residues from glycoproteins so newly budded virions detach and spread; oseltamivir and zanamivir competitively inhibit this enzyme, trapping virions at the cell surface. The M2 ion channel is blocked by amantadine and rimantadine, which are obsolete because circulating strains carry S31N resistance mutations. Cap-snatching endonuclease inhibition describes baloxavir marboxil, and hemagglutinin blockade is not an approved mechanism.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.