Aciclovir-Resistant HSV — SCE Infectious Diseases MCQ

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HardHIV MedicineAciclovir-Resistant HSVSCE Infectious Diseases

An adult with advanced HIV has progressive HSV-2 perianal ulceration despite adherent IV aciclovir. Genotyping shows a thymidine-kinase-deficient strain. Renal function is stable. Which antiviral is preferred?

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Correct answer: B — Intravenous foscarnet

Loss of viral thymidine kinase produces cross-resistance to aciclovir and valaciclovir and usually famciclovir. Foscarnet directly inhibits viral DNA polymerase without activation by thymidine kinase and is preferred; renal function, electrolytes and infusion-related toxicity require close monitoring.

Reference: BASHH anogenital herpes guideline 2024: https://www.bashh.org/_userfiles/pages/files/pateletal2024britishassociationofsexualhealthandhivuknationalguidelineforthemanagementofanogenital.pdf