Which antivirals are used for herpes viruses?

• A. Acyclovir, Valacyclovir, Famciclovir
• B. Oseltamivir
• C. Fluconazole
• D. Nystatin

Answer: (A)

Antivirals that target herpesviruses work as nucleoside analogs that must be activated by the virus-encoded thymidine kinase. After activation, they inhibit viral DNA polymerase and cause chain termination, so viral replication is blocked mainly in infected cells. Acyclovir, valacyclovir, and famciclovir fit this pattern and are the drugs of choice for herpesviruses. Acyclovir is the classic agent, valacyclovir is its prodrug with much better oral bioavailability, and famciclovir is another prodrug that converts to penciclovir. Together they are active against herpes simplex viruses types 1 and 2 and varicella-zoster virus, and they’re used for both treatment and suppression of mucocutaneous lesions as well as shingles.

Other options in the list do not target herpesviruses: oseltamivir is used for influenza, while fluconazole and nystatin are antifungals (not antivirals).