Oseltamivir is effective against influenza A and B when given within 48 hours of symptom onset. Its antiviral action results from inhibition of:
- A The M2 ion channel protein required for viral uncoating
- B Neuraminidase, preventing cleavage of sialic acid residues and release of new virions from infected cells ✓
- C RNA-dependent RNA polymerase, blocking genomic replication
- D Hemagglutinin-mediated binding of virus to host cell receptors
Correct answer: B. Neuraminidase, preventing cleavage of sialic acid residues and release of new virions from infected cells
Explanation
Oseltamivir is a sialic acid analogue that inhibits viral neuraminidase. Without neuraminidase activity, hemagglutinin remains bound to sialic acid receptors on the cell surface and progeny virions clump together instead of being released, limiting spread within the respiratory tract. Amantadine blocks the M2 ion channel involved in uncoating, and no licensed influenza drug acts directly on hemagglutinin attachment.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.