Trifluridine (ophthalmic)
Anti-herpesvirus agents
Anti-herpesvirus agents
Antiviral eye drops for herpes simplex keratitis. They are also used for eye involvement in severe mpox.
Quick facts
- Group
- Anti-herpesvirus agents
- Target
- Viral DNA synthesis (thymidylate synthase and DNA polymerase)
- Used for
- Primary keratoconjunctivitis
- Key effects
- Burning or stinging on instillation · Eyelid swelling
- Monitor
- Corneal healing on slit-lamp examination
- ATC
- S01AD02
No doses: the clinician sets them by the current guideline.
Mechanism of action
Trifluridine is a fluorinated pyrimidine nucleoside. Its monophosphate inhibits thymidylate synthase, and its triphosphate competes with thymidine triphosphate and is built into viral and cellular DNA, which stops normal DNA synthesis. It is active against herpes simplex virus types 1 and 2, including aciclovir-resistant strains, and against vaccinia. Because it also affects human cells, it is used only on the eye.
- Trifluridine is phosphorylated in the cell
- Its monophosphate inhibits thymidylate synthase
- Its triphosphate is built into viral DNA
- Viral DNA synthesis fails
Indications
- Primary keratoconjunctivitis and recurrent epithelial keratitis due to herpes simplex virus types 1 and 2 Keratitis and corneal ulcer →
- Eye involvement in severe mpox, together with tecovirimat Mpox →
Adverse effects
Common
- Burning or stinging on instillation
- Eyelid swelling
- Punctate keratopathy and irritation
Contraindications
- Hypersensitivity or chemical intolerance to trifluridine
Key interactions
- Systemic medicines
- No interactions are listed; systemic absorption appears negligible
What is monitored
- Corneal healing on slit-lamp examination
- Signs of epithelial toxicity
- Intraocular pressure
Administration and safety
- Instilled onto the cornea of the affected eye at frequent intervals while awake, as prescribed
- Continuous use beyond the recommended period is avoided because of corneal toxicity
- The dropper tip does not touch the eye
Pregnancy and breastfeeding
Systemic exposure is minimal and animal studies were not teratogenic; it is used in pregnancy only when needed.
Nursing care
- Explain that brief stinging is expected
- Teach correct drop technique and hand hygiene
- Report pain, worse vision or no improvement to the ophthalmologist
- Keep track of the total days of treatment
Pharmacokinetics
- Absorption
- Penetrates the cornea; systemic absorption after eye drops appears negligible
- Half-life
- Very short in the body, which limits exposure
Test yourself
Think of the answer, then tap the question to see it.
Why is trifluridine used only on the eye?
It also inhibits human DNA synthesis, so it is too toxic for systemic antiviral use.
Is trifluridine active against aciclovir-resistant herpes simplex?
Yes. It inhibits herpesviruses, including aciclovir-resistant strains.
Why is prolonged use avoided?
It can damage the corneal epithelium.
Connections
← Back to the class: Anti-herpesvirus agents
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - TRIFLURIDINE solution (DailyMed (U.S. National Library of Medicine), 2026); Interim Clinical Treatment Considerations for Severe Manifestations of Mpox — United States, February 2023 (Centers for Disease Control and Prevention (MMWR), 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.