Sorivudine: a potent inhibitor of varicella zoster virus replication

Sorivudine provides a unique nucleoside analog with significantly enhanced both in vitro as in vitro activity toward VZV and enhanced oral bioavailability, as compared with existing antivirals. Early indications from controlled studies, while not peer reviewed, indicate that sorivudine therapy is superior to acyclovir for the treatment of localized zoster in individuals with HIV Infection and chicken pox in adults. These studies await peer evaluation. One might question, as these data unfold, the relative clinical value of antivirals with such enhanced in vitro activity and oral bioavailability as compared to standard compounds. Should these drugs induce accelerated healing, but not as dramatically as would have been anticipated from the in vitro data, new approaches to the management of herpes zoster will need to be developed if further improvement is desired. Despite this provision, sorivudine therapy does appear to result in significantly accelerated healing of cutaneous zoster as compared to acyclovir, and sorivudine can be administered once daily in a dose that is one-hundredth that of acyclovir, and less than one tenth of the doses of valacuyclovir or famciclovir. These findings in and of themselves should allow for licensure of the compound in developed societies.