Trifluridine, antiviral agent

The metabolic fate of trifluridine (11.17), an antiviral agent closely related to 5-fluoro-2 -deoxyuridine, was comparable. The main metabolite in the urine of mice administered the drug was the free 5-trifluorothymidine, i. e., the product of C-N bond cleavage [39]. All other metabolites were products of further biotransformation of trifluorothymidine. 

Idoxuridine (9.7) and trifluridine (9.8) are antiviral agents that are phosphorylated to their active form in virus-infected cells, and thus show specificity for two reasons their higher affinity for the viral enzyme, and the higher phosphorylase levels in viral-infected than in normal cells. Both compounds have been used locally on lesions of HSV-1 and HSV-2 (the latter of which causes genital herpes, now reaching epidemic proportions) with fair success. They are rather toxic if administered parenterally, as are all moderately selective antimetabolities. 

Herpetic conjunctivitis without corneal involvement usually is benign and self-limited. In patients with primary herpetic blepharoconjunctivitis, prophylactic treatment with antiviral agents to prevent corneal involvement is common practice. Trifluridine (Viroptic) usually is well tolerated and is effective against many strains of HSV. The typical dose is one drop every 2 hours for a maximum... 

The use of topical ophthalmic antiviral agents such as idoxuridine and adenine arabinoside generally has been found to be ineffective in the treatment of EKC. However, 1% trifluridine has been shown to decrease replication of adenovirus types 8,13, and 19 in vitro, though no strong evidence exists for its use in EKC patients. 

Trifluridine, an antiviral agent (1 drop of 1% solution onto the cornea), is nsed every 2 honrs while awake until the corneal nicer has reepithelialized completely. Trifluridine is indicated for primary keratoconjnnctivitis and recurrent epithelial keratitis dne to herpes simplex virus types 1 and 2. In addition, it is nsed for epithelial keratitis that has not responded clinically to topical idoxnridine, or when ocular toxicity or hypersensitivity to idoxnridine has occurred. 

---