Effect of phosphonoacetic acid in the treatment of experimental herpes simplex keratitis

In the rabbit 5% phosphonoacetic acid ointment suppressed herpetic keratitis as well as 0-5% idoxuridine ointment. After 5 days of treatment quantitative virus titres showed that phosphonoacetic acid was superior to idoxuridine in the inhibition of herpes virus replication. Phosphonoacetic acid was found to be nontoxic to the eye in both clinical and histopathological studies. Recent reports suggest that the mechanism of action of phosphonoacetic acid appears to be the blocking of the virus DNA polymerase, which is essential for the synthesis of herpes virus DNA.