Contemporary antiviral drug regimens for the prevention and treatment of orolabial and anogenital herpes simplex virus infection in the normal host: Four approved indications and 13 off-label uses

Management of herpesvirus infections

Management of human herpesviruses remains a considerable clinical challenge, in part due to their ability to cause both lytic and latent disease. Infection with the Herpesviridae results in lifelong infection, which can reactivate at any time. Control of herpesviruses is by the innate and adaptive immune systems. Herpesviruses must evade the host innate immune system to establish infection. Once infected, the adaptive immune response, primarily CD8(+) T-cells, is crucial in establishing and maintaining latency. Latent herpesviruses are characterised by the presence of viral DNA in infected cells and limited or no viral replication. These characteristics provide a challenge to clinicians and those developing antiviral agents. The scope of this review is two-fold. First, to provide an overview of all antivirals used against herpesviruses, including their mechanism of action, pharmacokinetics, side effects, resistance and clinical uses. And second, to address the management of each of the eight herpesviruses both in the immunocompetent and immunocompromised host, providing evidence for clinical management and therapeutic options, which is important to the clinician engaged in the management of these infections.

Famciclovir: a focus on efficacy and safety

IMPORTANCE OF THE FIELD

Famciclovir is the prodrug of penciclovir, a guanosine analogue that inhibits viruses of the alpha sub-family of the Herpesviridae, as well as hepatitis B virus. It is indicated for management of mucocutaneous herpes simplex virus disease and acute herpes zoster, and has been investigated for management of hepatitis B virus infection.

AREAS COVERED IN THIS REVIEW

Data for this review were identified by searches of papers published in English on Medline and Scopus, spanning the years 1975 through 1 February 2010 with the key words: 'famciclovir', 'famvir', 'penciclovir', 'herpes', 'oral', 'genital', 'varicella', 'zoster' and 'virus' in association with 'safety', 'toxicity', 'tolerability', 'efficacy' and 'indications'. Relevant references were also obtained from articles acquired through the search strategy.

WHAT THE READER WILL GAIN

Readers are also provided with up-to-date information on the use of famciclovir for infections due to herpes simplex, varicella zoster and hepatitis B viruses. Clinical data pertaining to the safety and tolerability of famciclovir are also reviewed.

TAKE HOME MESSAGE

Famciclovir is a safe, convenient, and well-tolerated drug when used for its approved indications. The most common side effects indicated in the majority of studies were headache and nausea. Data for its use in childhood and pregnancy are limited.