What is the action of the antiviral drug oseltamivir in influenza therapy?

Oseltamivir is an antiviral medication specifically designed to treat influenza. Its mechanism of action is centered on the inhibition of the neuraminidase enzyme, which is crucial for the influenza virus's life cycle. Neuraminidase is responsible for cleaving sialic acid residues on the surface of infected cells, facilitating the release of newly formed viral particles from the host cell. By inhibiting this enzyme, oseltamivir prevents the release of virus particles, thereby reducing the spread of the virus within the respiratory tract and slowing down the progression of the infection. This action enhances the effectiveness of the body's immune response against the virus and helps alleviate the severity and duration of influenza symptoms.

The other potential choices do not apply to oseltamivir's action; for example, inhibiting viral polymerase refers to the mechanism of drugs like ribavirin or favipiravir, while inhibiting RNA transcription is not applicable to any specific influenza drugs. Blocking viral entry into cells is a mechanism utilized by other antiviral agents but not oseltamivir, which operates at a different stage of the viral life cycle.