Vibardine

Vidarabine is an adenine analog and has activity against HSV, VZV, and CMV. Its use for systemic infections is limited by rapid metabolic inactivation and marked toxic potential. Vidarabine is used topically for herpes keratitis but has no effect on genital lesions. Toxic effects with systemic use include GI irritation, paresthesias, tremor, convulsions, and hepatic dysfunction. Vidarabine is teratogenic in animals.  (arabinofuranosyl adenine, ara-A, adenine arabinoside) is one of the most effective of the nucleoside analogs. However, it has been supplanted clinically by acyclovir, which is more efficacious and safe. Although vidarabine is active against HSV-1, HSV-2, and VZV, its use is limited to treatment of immunocompromised patients with herpetic and vaccinial keratitis and in HSV keratoconjunctivitis. [Note: Vidarabine is only available as an ophthalmic ointment.] Vidarabine, an adenosine analog, is converted in the cell to its 5’-triphosphate analog (ara-ATP), which is postulated to inhibit viral DNA synthesis. Some resistant HSV mutants have been detected that have altered polymerase.