Herpes Labialis Prophylaxis — ORE Part 1 MCQ

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ModerateOral MedicineHerpes Labialis ProphylaxisORE Part 1

An immunocompetent adult has recurrent herpes labialis, with approximately six clinically typical episodes each year. After discussion of benefits and adverse effects, which prophylactic regimen may be considered?

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Correct answer: E — Oral aciclovir 400 mg twice daily, reviewed after 6–12 months

**A is correct.** For troublesome, frequently recurrent herpes labialis, suppressive oral aciclovir is an evidence-based option. The UK aciclovir SmPC states that 400 mg twice daily is a convenient regimen for suppressing recurrent HSV infection and advises periodic interruption after 6–12 months to reassess need. A randomised placebo-controlled trial specifically in frequently recurrent herpes labialis found that aciclovir 400 mg twice daily reduced recurrences. Topical aciclovir cream is licensed for treatment of individual cold-sore episodes, rather than continuous suppression. Amoxicillin has no activity against HSV. Continuous topical corticosteroid could worsen viral infection and is not prophylaxis. Lysine is sometimes proposed by patients, but it is not an evidence-based antiviral suppressive regimen in UK practice.

Reference: Wockhardt UK Ltd. Aciclovir 800 mg Tablets: Summary of Product Characteristics, section 4.2, updated 2026. https://www.medicines.org.uk/emc/product/2351/smpc