Treatment of herpetic keratitis

Idoxuridine which was first used in 1960 (Kaufman et al., 1962), has been for many years the only antiviral agent available in the treatment of herpetic keratitis. It is however no more successful than is mechanical removal of diseased epithelium (Patterson & Jones, 1967), and furthermore it may give rise to serious toxic side effects. The search for an alternative medication is therefore a pressing one. Trifluorothymidine (F3T) has, in recent years, been shown to be more effective than IDU and to be free from significant toxicity. Both of these drugs are pyrimidine nucleosides. Adenine Arabinoside or Arabinoside-A (Ara-A) is, by contrast, a purine nucleoside. It is thought to exert its antiviral effect by blocking DNA polymerase and ribonucleotide reductase.