Question | Discussion | References | CME Credit

Case 2: Acyclovir-Resistant Herpes Simplex Virus Infection

You answered:

B Famciclovir (Famvir) 500 mg PO tid.

This answer is incorrect. Most acyclovir-resistant herpes simplex virus infections result from decreased viral production of thymidine kinase, the enzyme responsible for the first phosphorylation step in converting acyclovir to its active triphosphorylated form acyclovir triphosphate. Famciclovir (Famvir) is a prodrug of penciclovir and because activation of penciclovir also depends on viral thymidine kinase, acyclovir resistance generally also causes famciclovir resistance.

Choose another answer:

A Acyclovir (Zovirax) 10 mg/kg IV q8h.
C Foscarnet (Foscavir) 40 mg/kg IV q8h.
D Valacyclovir (Valtrex) 1000 mg PO tid.

[Back to Case 2 Question | Go to Correct Answer]