Treatment of choice for infections caused by herpes simplex virus is:

• A. Acyclovir (Zovirax)
• B. Ganciclovir
• C. Zidovudine
• D. Oseltamivir

Answer: (A)

Acyclovir works by inhibiting viral DNA synthesis after activation inside infected cells, making it the treatment of choice for herpes simplex virus infections. It is a nucleoside analogue that HSV thymidine kinase phosphorylates, converting it to the active triphosphate form. This active form selectively inhibits viral DNA polymerase and causes chain termination, effectively stopping HSV replication with relatively low toxicity to uninfected cells.

This drug is effective for both mucocutaneous herpes and more severe presentations, such as neonatal or disseminated HSV, where intravenous acyclovir is used to improve outcomes. Oral formulations (often as valacyclovir, a prodrug with good bioavailability) are suitable for less severe infections or recurrent episodes. Safety considerations include ensuring adequate hydration and monitoring renal function with IV therapy to prevent nephrotoxicity.

Ganciclovir is primarily used for CMV infections and has more myelosuppressive effects, zidovudine treats HIV, and oseltamivir targets influenza. That’s why acyclovir is the best choice for herpes simplex virus infections.