Famciclovir: new preparation. Slightly helpful in herpes zoster

Abstract

A comparative placebo-controlled trial involving 419 adults showed that a one-week course of famciclovir started within 3 days of onset of skin lesions had no effect on the acute phase of zoster, the time required for scabs to fall, the end of skin lesion progression, or pain. In this trial famciclovir failed to reduce the incidence of post-zoster pain, but it did reduce its median duration by approximately 2 months. According to a subgroup analysis (not planned for by the protocol), only patients over 50 benefited from this effect. Three other trials suggest that the approved dose regimen in France (500 mg 3 times a day) may not be optimal. The dose recommended in the United Kingdom (750 mg in one daily intake or 250 mg 3 times a day) seems to be more in line with the clinical assessment file. The three available comparative trials show no statistically significant difference between famciclovir and aciclovir in terms of efficacy or tolerability. An indirect comparison suggests that the risk-benefit ratio of famciclovir and valaciclovir are probably similar. However, the effects of famciclovir on post-zoster pain were observed in a clinical trial, while those of aciclovir were found only in meta-analyses.