Between Trifluridine and Ganciclovir, which topical anti-herpes agent has better bioavailability and efficacy?

• A. Trifluridine
• B. Ganciclovir
• C. Acyclovir
• D. Penciclovir

Answer: (B)

In topical anti-herpes therapy, how much drug actually gets into the infected tissue and how long it stays active there largely determines bioavailability and overall effectiveness. Trifluridine is rapidly metabolized in ocular tissues by enzymes like thymidine phosphorylase, which shortens its duration of action and requires very frequent dosing. It is also relatively cytotoxic to the corneal surface, which can limit its practical use and efficacy.

Ganciclovir, when used topically, penetrates the cornea effectively and is activated inside infected cells to a potent triphosphate form that inhibits viral DNA polymerase. This intracellular activation is fairly selective for infected cells, and the drug has a longer intracellular half-life, allowing effective viral suppression with less frequent dosing and better tolerability.

So, compared with trifluridine, ganciclovir offers better bioavailability at the ocular surface and greater antiviral efficacy for topical herpes infections.