A randomized controlled trial of acyclovir versus netivudine for treatment of herpes zoster. International Zoster Study Group.

Oral acyclovir has become the standard of care for treatment of acute herpes zoster. Netivudine is a novel antiviral with greater in-vitro activity against varicella zoster virus. It was compared with acyclovir in a randomized, double-blind, controlled trial in immunocompetent adults with herpes zoster. Patients with rash for less than 72 h were assigned to receive either acyclovir or netivudine, then assessed regularly for 6 months. No evidence for a dose response with netivudine was found, so intent-to-treat analyses of all 511 enrolled patients compared acyclovir with netivudine. The time to complete cessation of pain (P = 0.007) and to cessation of moderate to excruciating pain (P = 0.005) was accelerated in acyclovir recipients. Rash outcomes and adverse event profiles were similar for both treatments. This study has confirmed the efficacy of acyclovir in decreasing the duration and severity of pain following herpes zoster. Greater in-vitro activity of newer agents may not necessarily provide greater benefit in humans.