I have suffered from outbreaks of ocular herpes for more than 10 years. When I have an outbreak, I treat with acyclovir (400mg dose). If severe, I use Viroptic drops in combination with the acyclovir. My husband and I want to start a family, and I am really concerned about how to treat an outbreak while I am pregnant. Is it safe to continue with my regular treatment? If not, what other options are available?

L.

You are right be concerned, because the herpes virus is responsible for many cases of corneal-related blindness. Typically, people with ocular herpes experience multiple bouts of corneal inflammation. If not promptly and properly treated, these episodes of inflammation can cause scarring of the cornea, which can result in vision loss and even blindness.

The treatment of ocular herpes usually involves antiviral eyedrops and oral antiviral medications. Currently, the most effective antiviral drop to treat herpes is the drug that you are taking, trifluridane (Viroptic). This medication interferes with the virus's ability to make DNA, resulting in the death of the virus.

Viroptic is very safe with minimal side effects. However, if a woman is pregnant, our protocols for using many medications, including eyedrops, often changes. I was unable to find any studies on the risks of Viroptic during pregnancy. According the Physicians' Desk Reference, which is the authoritative guide to prescription drugs, Viroptic eyedrops were tested in pregnant rabbits on the sixth through 18th days of gestation. This study found no toxic effects to the rabbits' offspring. However, in other studies, Viroptic caused some mild problems in the offspring of pregnant rats and rabbits when it was injected at a dose 23 times the level found in eyedrops. With these studies in mind, the official prescribing information states that Viroptic should only be used during pregnancy if the potential benefit to the mother justifies the potential risk to the fetus.

A recent study in the New England Journal of Medicine found that acyclovir, the oral medication that you are taking, can reduce the risk of ocular herpes recurrence by 50 percent. Therefore, many patients are kept on oral acyclovir for a year or more after their last recurrence. Like Viroptic, acyclovir interferes with viral DNA synthesis, causing viral death. There have been no formal studies of acyclovir during pregnancy that I could find. The Physicians' Desk Reference reports that super-high doses of acyclovir did not cause problems when tested on mice, rats and rabbits during pregnancy. However, since acyclovir works by damaging viral DNA, caution is still warranted when considering this medication during pregnancy. Like Viroptic, the official prescribing information for acyclovir states that the drug should only be used during pregnancy if the potential benefit to the mother justifies the potential risk to the fetus.

Hopefully, during your pregnancy, the herpes infection of your cornea would not recur and you would not have to take Viroptic or acyclovir. However, if you did suffer an outbreak, you would need to work closely with your doctor to decide when and how to treat your infection to minimize damage to your cornea. These situations can be very difficult for both the mother and doctor, so careful, individualized care is required.