The role of antivirals in the management of neuropathic pain in the older patient with herpes zoster.

Herpes zoster has been known since ancient times. It is a ubiquitous disease, occurring sporadically without any seasonal preference and is caused by the varicella-zoster virus. It may be defined as an endogenous relapse of the primary infection varicella. Herpes zoster is characterised by typical efflorescences in the innervation region of a cranial or spinal nerve and starts and ends with pain of varying intensity. Currently, several antiviral drugs are approved and many studies have shown that antiviral therapy, started early in the course of disease, can significantly reduce the risk and the duration of postherpetic neuralgia in elderly patients. The effects of all antivirals discussed in this article, given either orally or intravenously, are comparable with regards to the resolution of virus replication, prevention of dissemination of skin lesions and reduction of acute herpes zoster pain. Valaciclovir (valacyclovir), famciclovir and brivudine (brivudin) are comparably effective in the reduction of the incidence and/or prevention of zoster-associated pain and postherpetic neuralgia. Brivudine 125mg once daily is as effective as famciclovir 250mg three times daily in reducing the prevalence and the duration of zoster-associated pain and postherpetic neuralgia, especially if therapy is combined with a structured-pain therapy. The intensity of the therapy for pain should depend on the intensity of the pain that it is treating. Famciclovir and brivudine offer an advantage over other antivirals because they are administered less frequently; this is particularly relevant for elderly patients who may already be taking a number of medications for other diseases. Therefore, antiviral therapy in combination with adequate pain management should be given to all elderly patients as soon as herpes zoster is diagnosed.