Increasing age of the population will increase the incidence of herpes zoster for the foreseeable future unless HZ vaccination becomes widely adopted. Postherpetic neuralgia remains the most common complication of HZ and, despite advances, its treatment remains less than satisfactory. The only practical and proven means of reducing the duration of pain associated with HZ at the present time is by early use of antiviral drugs.

Although currently available antivirals do not totally prevent PHN, they reduce duration of pain significantly with a very acceptable safety profile. Aciclovir requires 5 times daily administration because of poor oral bioavailability. Newer drugs have been investigated using once daily, twice daily and 3 times daily administration which offer patients a more convenient dosing schedule. Apart from brivudin, which is not universally licensed and is contraindicated in immunocompromised patients, no antiviral has yet been shown to reduce duration of pain associated with HZ with once daily administration although famciclovir 750mg once daily controls acute pain and rash effectively.

It is possible that shorter courses of famciclovir, perhaps in a higher dose once daily, might provide equivalent benefit to that achieved with 250 or 500mg 3 times daily for 7 days. Do the pathophysiology of HZ and drug characteristics of famciclovir make this a realistic goal?

At the present time, antiviral pro-drugs remain the treatment of choice for HZ for controlling acute pain and rash as well as reducing duration of pain. In addition they reduce less common complications such as occur with zoster ophthalmicus.