Drugs can lower risk of genital herpes recurrence

NEW YORK (Reuters Health) - The effectiveness of oral antiviral drugs, commonly used to prevent genital herpes outbreaks in infected patients, has been confirmed by a review of published studies.

The researchers evaluated acyclovir, valacyclovir, and famciclovir, sold under the trade names Zovirax, Valtrex and Famvir, respectively, in a "meta-analysis," a review strategy in which the results of several published trials are analyzed to obtain information from a larger total number of patients, which provides the ability to draw more statistically significant conclusions.

Although the use of these drugs to prevent herpes outbreaks began in the early 1980s, the present study is the first meta-analysis to examine their effectiveness compared with placebo, note Dr. Benedicte Lebrun-Vignes, from Hopital Pitie-Salpetriere in Paris, and colleagues in the Journal of the American Academy of Dermatology.

Their review included 14 clinical trials with a total of 6,158 patients with sound immune systems and who were not pregnant. (The drugs should never be taken during pregnancy because they can cause birth defects.)

The investigators found that patients who were given one of the three drugs were 47-percent less likely to experience a genital herpes recurrence than those given placebo, the report indicates.

The three agents tested were generally comparable in efficacy. The best regimens for preventing a recurrence were acyclovir 400 mg, valacyclovir 250 mg, or famciclovir 250 mg -- all given twice daily -- or valacyclovir 500 mg given once daily.

Lebrun-Vignes and associates conclude that all three drugs are suitable treatments for preventing genital herpes outbreaks. However, the authors emphasize the importance of monitoring patients for the possible emergence of drug resistance in patients who do not respond to the standard regimens.

Journal of the American Academy of Dermatology. August 2007.