Oseltamivir (Tamiflu) for influenza acts by inhibiting neuraminidase. The clinical consequence of untreated neuraminidase activity is:

• A Insertion of influenza hemagglutinin into the endosomal membrane, preventing viral uncoating
• B Cleavage of sialic acid residues on host cell surfaces, releasing newly formed virions for systemic spread ✓
• C Replication of the influenza negative-sense RNA genome by the viral RNA-dependent RNA polymerase
• D Transcytosis of secretory IgA by sialic acid receptor-mediated endocytosis

Explanation

Influenza neuraminidase cleaves sialic acid residues on the surface of infected host cells, allowing newly assembled virions to detach and spread to adjacent cells and the respiratory tract. Without neuraminidase inhibition, virions remain tethered to the host cell via hemagglutinin-sialic acid bonds, limiting their spread. Oseltamivir is most effective when started within 48 hours of symptom onset; it reduces symptom duration and severity.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.