Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Trifluridine is a nucleoside analogue that is built into DNA in place of thymidine and disrupts it. As eye drops (Viroptic) it treats herpes simplex infections of the eye. Combined with tipiracil as tablets (Lonsurf), it is a chemotherapy for advanced bowel and stomach cancers after other treatments; tipiracil blocks the enzyme that would otherwise break trifluridine down quickly.
The gene studies on this page concern the cancer use (Lonsurf). They looked at SLC29A1, the carrier that takes trifluridine into cells, and at the kidney transporters SLC22A2 and SLC47A1, for how well treatment worked. The findings come from a few studies, and there is no CPIC or DPWG guideline.
Every published finding on gene variants and Trifluridine. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
SLC29A1 rs9394992: Level 3. Efficacy: Colorectal Neoplasms. 1.
SLC29A1 rs760370: Level 3. Efficacy: Colorectal Neoplasms. 1.
Studies of how well it worked in people carrying a variant.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Agenerase (Protease Inhibitors)
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
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