synthetase, and the biologically generated triphosphate competitively inhibits thymidine triphosphate incorporation into DNA by DNA polymerase. In addition, trifluridine in its triphosphate form is incorporated into viral and cellular DNA, creating fragile, poorly functioning DNA.

Trifluridine is approved in the United States for the treatment of primary keratoconjunctivitis and recurrent epithelial keratitis caused by HSV types 1 and 2. Topical trifluridine shows some efficacy in patients with acyclovir-resistant HSV cutaneous infections. Trifluridine solutions are heat sensitive and require refrigeration.


Chemically, vidarabine (Vira-A), is 9-jS-d-arabinofuranosy-ladenine. The drug is the 2' epimer of natural adenosine. Introduced in 1960 as a candidate anticancer agent, vidara-bine was found to have broad-spectrum activity against DNA viruses.34 The drug is active against herpesviruses, poxviruses, rhabdoviruses, hepadnavirus, and some RNA tumor viruses. Vidarabine was marketed in the United States in 1977 as an alternative to idoxuridine for the treatment of HSV keratitis and HSV encephalitis. Although the agent was initially prepared chemically, it is now obtained by fermentation with strains of Streptomyces antibioticus.

Free Yourself from Panic Attacks

Free Yourself from Panic Attacks

With all the stresses and strains of modern living, panic attacks are become a common problem for many people. Panic attacks occur when the pressure we are living under starts to creep up and overwhelm us. Often it's a result of running on the treadmill of life and forgetting to watch the signs and symptoms of the effects of excessive stress on our bodies. Thankfully panic attacks are very treatable. Often it is just a matter of learning to recognize the symptoms and learn simple but effective techniques that help you release yourself from the crippling effects a panic attack can bring.

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