Which antiviral is used specifically for influenza rather than herpes?

• A. Oseltamivir (Tamiflu)
• B. Acyclovir
• C. Valacyclovir
• D. Nystatin

Answer: (A)

Influenza-focused antivirals work by blocking a step unique to the influenza virus lifecycle. Oseltamivir is a neuraminidase inhibitor that prevents newly formed influenza virions from being released from infected cells, which slows or stops the spread of the virus in the body. It treats influenza A and B and is most effective when started early, ideally within 48 hours of symptoms beginning. It’s not active against herpesviruses, which are treated with different antivirals that target herpes DNA replication.

Acyclovir and valacyclovir, for example, are nucleoside analogs that require activation by viral thymidine kinase and then inhibit viral DNA polymerase to treat herpes infections. Nystatin is an antifungal, not an antiviral, so it doesn’t treat viral infections at all. Therefore, the antiviral used specifically for influenza rather than herpes is oseltamivir.