Herpes zoster antivirals and pain management

Abstract

Topic: Evaluation of evidence-based strategies for managing herpes zoster (HZ) and the pain of postherpetic neuralgia (PHN).

Clinical relevance: Approximately 20% of the world's population suffers from herpes zoster at least once in a lifetime, with 10% to 20% having ophthalmic involvement. Treatment of the acute disease with oral antivirals may reduce the incidence and severity of complications but does not reliably prevent PHN or postherpetic itch (PHI). The acute pain abates as the acute phase resolves; the long-term pain of PHN or PHI may be severe and difficult to manage. Although many therapeutic agents have efficacy in the management of these complications, relief is frequently partial for months to the remainder of the lifetime.

Methods: Literature review was performed using the resources of the Harvard Medical School/Massachusetts Eye and Ear Infirmary Ophthalmic library as well as the National Library of Medicine and the National Institutes of Health PubMed service searching by pertinent topics, authors, and journals.

Results: If started within 72 hours of the onset of the acute HZ rash, the oral antiviral agents acyclovir, valacyclovir, and famciclovir significantly shorten the periods of acute pain, virus shedding, rash, acute and late-onset anterior segment complications, and, in the case of valacyclovir and famciclovir, the incidence and severity of PHN. However, these medications do not prevent PHN, which remains a common and debilitating complication of HZ in older patients, requiring assiduous pain management. Tricyclic antidepressants, antiseizure drugs, opioids, and topical analgesics all offer some pain relief, and may be combined.

Conclusion: Options are available to manage HZ and reduce the pain of PHN. However, prevention, now possible with the HZ vaccine, is preferable to treatment.