Oseltamivir (Tamiflu) is effective against influenza A and B. Its mechanism of action is:
- A Inhibition of viral haemagglutinin preventing receptor binding to sialic acid
- B Inhibition of viral RNA-dependent RNA polymerase (cap-dependent endonuclease)
- C Inhibition of viral neuraminidase preventing release of progeny virions from infected cells ✓
- D Blocking M2 ion channel preventing viral uncoating
Correct answer: C. Inhibition of viral neuraminidase preventing release of progeny virions from infected cells
Explanation
Neuraminidase inhibitors (oseltamivir, zanamivir, peramivir) block viral neuraminidase, which normally cleaves sialic acid residues from host cell surface glycoproteins to allow newly formed virions to be released. Without this, progeny virions aggregate on the cell surface and cannot disseminate. M2 channel blockers (amantadine, rimantadine) work by blocking uncoating but are only effective against influenza A. Baloxavir marboxil inhibits cap-dependent endonuclease (PA subunit of RNA polymerase). Haemagglutinin is not a current drug target.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.