Which Anti-Herpes medication is administered via IV and primarily used in resistant herpes infections?

Which Anti-Herpes medication is administered via IV and primarily used in resistant herpes infections?

• A. Acyclovir
• B. Foscarnet
• C. Valacyclovir
• D. Ganciclovir

Answer: (B)

When a herpes infection no longer responds to standard drugs, you need an antiviral that works without needing activation by the virus’s kinases. Foscarnet does just that: it directly inhibits viral DNA polymerase by binding at the pyrophosphate site, so it’s active even if the virus has mutated its thymidine kinase. Because it’s not a prodrug and has poor oral bioavailability, it’s given intravenously, making it ideal for resistant HSV infections. In contrast, acyclovir and its prodrug valacyclovir require phosphorylation by viral kinases to become active and are less reliable when resistance involves those kinases. Ganciclovir targets CMV more than resistant HSV. So the IV agent best suited for resistant herpes infections is foscarnet.

When a herpes infection no longer responds to standard drugs, you need an antiviral that works without needing activation by the virus’s kinases. Foscarnet does just that: it directly inhibits viral DNA polymerase by binding at the pyrophosphate site, so it’s active even if the virus has mutated its thymidine kinase. Because it’s not a prodrug and has poor oral bioavailability, it’s given intravenously, making it ideal for resistant HSV infections. In contrast, acyclovir and its prodrug valacyclovir require phosphorylation by viral kinases to become active and are less reliable when resistance involves those kinases. Ganciclovir targets CMV more than resistant HSV. So the IV agent best suited for resistant herpes infections is foscarnet.