Antiviral drugs in development for herpes zoster.

Until recently aciclovir has been the only licensed drug for the treatment of herpes zoster. A number of new drugs have emerged over the past few years which offered the potential for improved efficacy or ease of administration. With the completion of the first efficacy trials for each of these agents it has become apparent that, whilst less frequent dosing can he accomplished, it is not easy to significantly improve on the efficacy of aciclovir. Increasing age, the presence of prodromal pain and more severe pain at presentation have, however, been found to predispose to a longer duration of pain. Taking cessation of pain as the single most important parameter, at least for the older immunocompetent population as a whole, only valaciclovir has, to date, been shown to be superior to standard therapy with aciclovir. This review utilises primarily intent-to-treat data to illustrate the relative efficacy of the different therapies.