Trifluridine (also called trifluorothymidine; abbreviation TFT or FTD[1]) is an anti-herpesvirusantiviral drug, used primarily as prescription eyedrops. It was sold under the trade name Viroptic by Glaxo Wellcome, now merged into GlaxoSmithKline. The brand is now wholly owned by King Pharmaceuticals.
Trifluridine was approved for medical use in 1980.[2] It is also a component of the anti-cancer drug trifluridine/tipiracil, which is taken by mouth.
Common side effects of trifluridine eye drops include transient burning, stinging, local irritation, and edema of the eyelids.[3]
Adverse effects of the anti-cancer formulation have only been evaluated for the combination trifluridine/tipiracil, not for the individual components.[citation needed]
Trifluridine passes the cornea and is found in the aqueous humour. Systemic absorption is negligible.[3]
Pharmacokinetics (oral)
Pharmacokinetic data of oral trifluridine have only been evaluated in combination with tipiracil, which significantly affects biotransformation of the former. At least 57% of trifluridine are absorbed from the gut, and highest blood plasma concentrations are reached after two hours in cancer patients. The substance has no tendency to accumulate in the body. Plasma protein binding is over 96%. Trifluridine is metabolised by the enzyme thymidine phosphorylase to 5-trifluoromethyl-2,4(1H,3H)-pyrimidinedione (FTY), and also by glucuronidation. Elimination half-life is 1.4 hours on the first day and increases to 2.1 hours on the twelfth day. It is mainly excreted via the kidneys.[5]
Tipiracil causes Cmax (highest blood plasma concentrations) of trifluridine to increase 22-fold, and its area under the curve 37-fold, by inhibiting thymidine phosphorylase.[5]
^Kimberlin DW (2012). "Antiviral Agents". In Long SS, Pickering LK, Prober CG (eds.). Principles and Practice of Pediatric Infectious Disease. Elsevier Health Sciences. p. 1502. ISBN978-1437727029.
Costin D, Dogaru M, Popa AS, Cijevschi I (2004). "[Trifluridine therapy in herpetic in keratitis]" [Trifluridine therapy in herpetic in keratitis]. Revista Medico-Chirurgicala a Societatii de Medici Si Naturalisti Din Iasi (in Romanian). 108 (2): 409–412. PMID15688823.
Kuster P, Taravella M, Gelinas M, Stepp P (April 1998). "Delivery of trifluridine to human cornea and aqueous using collagen shields". The CLAO Journal. 24 (2): 122–124. PMID9571274.
O'Brien WJ, Taylor JL (August 1991). "Therapeutic response of herpes simplex virus-induced corneal edema to trifluridine in combination with immunosuppressive agents". Investigative Ophthalmology & Visual Science. 32 (9): 2455–2461. PMID1907950.