Which Anti Herpes Agent contains the thimerosal preservative?

• A. Trifluridine (Viroptic)
• B. Ganciclovir (Zirgan)
• C. Acyclovir
• D. Valacyclovir

Answer: (A)

Thimerosal is a mercury-containing preservative historically used in multi-dose ophthalmic solutions to prevent microbial growth. Among the anti-herpes options, the topical trifluridine eye drops are the ones that have been formulated with thimerosal as their preservative. The other agents listed are not typically provided with thimerosal in their ophthalmic formulations (and in the case of valacyclovir, it is an oral drug, so a preservative context isn’t applicable). In modern practice, many eye drops have moved away from thimerosal, using alternative preservatives or being preservative-free in single-use packaging.