Topical ganciclovir safe, effective for herpes keratitis

In a small interventional case series, Dr. Tabbara prescribed topical ganciclovir for the treatment of 16 cases of herpetic keratitis. Six patients had geographic epithelial dendritic ulcers and 10 had epithelial corneal ulcers. Of the six patients, three had already received corneal grafts. Patients ranged in age from 26 to 80 years (mean, 47 years) and 12 of the patients were male.

The anti-viral agent was administered every 6 hours for 2 weeks and then some of the patients continued with twice-daily prophylactic treatment with ganciclovir for an average of 11 months, noted Dr. Tabbara, medical director, The Eye Center, Riyadh, Saudi Arabia.

"Following healing of the herpetic keratitis, we selected six patients who had previous episodes of herpetic keratitis and treated them with prophylactic ganciclovir twice a day for an average of 11 months," Dr. Tabbara said. "Ten patients did not receive prophylaxis."

Topical ganciclovir appears to be fairly safe because no patients developed hematologic changes during follow-up or ocular surface complications from ganciclovir prophylaxis, he said.

Other anti-viral agents such as idoxuridine (Herplex, Allergan), vidarabine (Vira-A, Monarch), trifluridine (Viroptic, Monarch), and acyclovir (Zovirax, GlaxoWellcome), have also been used for treating herpetic keratitis. However, prolonged use of these thymidine analogues poses a risk to the ocular surface, including epithelial keratitis, corneal ulcer, follicular conjunctivitis, and punctal occlusion, Dr. Tabbara noted.

"Ganciclovir is a potent inhibitor of members of the herpes family and has been used extensively for the treatment of CNV retinitis in patients with AIDS. It has reached therapeutic levels for topical application in the cornea," he continued.

Topical ganciclovir appears to be well tolerated and does not cause any toxic effects on the ocular surface, Dr. Tabbara said.

Others have also demonstrated the effectiveness of ganciclovir ophthalmic gel for the treatment of herpetic keratitis, as shown in the literature. Colin and colleagues published a report in Cornea in 1997, which included two multicenter, randomized studies in Africa and Europe. They concluded that the topical agent was effective for the treatment of corneal ulcers in patients with herpes simplex keratitis and that ganciclovir was better tolerated than acyclovir ointment, reported Terrence P. O'Brien, MD, who discussed the paper.

In an extensive review, Wilhelmus undertook a meta-analysis of the treatment of herpes simplex virus epithelial keratitis. Debridement of the infected area combined with anti-viral agents may be more effective than anti-viral therapy alone, but the results in the literature are inconclusive. Dr. Wilhelmus also reported that topical anti-viral agents-bromovinyldeoxyuridine, ganciclovir, and foscarnet (Foscavir, Astra)-are similar to trifluridine or acyclovir in the treatment of epithelial keratitis. His report was published in the Transactions of the American Ophthalmological Society in 2000, said Dr. O'Brien, professor of ophthalmology and director of ocular infectious diseases, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore.